Total Energy Expenditure, Energy Intake, and Body Composition in Endurance Athletes Across the Training Season: A Systematic Review

Multidimensional Differences Between Athletes of Endurance, Strength, and Intermittent Sports: Body Composition, Diet, Resting Metabolic Rate, Physical Activity, Sleep Quality, and Subjective Well-Being

Background/Objectives: Sports performance is influenced by a complex interplay of physical, physiological, and psychological factors, which differ across disciplines. Thus, this study aims to identify and compare the distinct multidimensional profiles (i.e., body composition, diet, resting metabolic rate, physical activity, sleep quality, and subjective well-being) of athletes from different sports disciplines (i.e., endurance, strength, and intermittent sports). Methods: This study included 77 athletes (28 women) classified as endurance (n = 40), strength (n = 12), or intermittent (n = 25). Body composition was assessed by dual-energy X-ray absorptiometry, bioimpedance, and anthropometry, diet was determined using dietary recalls, resting metabolic rate was assessed by indirect calorimetry, physical activity and sleep quality were determined by a wrist-worn accelerometer, and subjective well-being was determined through validated questionnaires. Results: Strength and intermittent athletes had greater body weight, lean mass, and bone parameters than endurance athletes, whereas intermittent athletes showed higher adiposity than endurance levels (all p ≤ 0.008). The endurance group did not exhibit a higher intake of fats or proteins compared to the strength and intermittent groups; however, it did demonstrate a higher consumption of carbohydrates (p ≤ 0.016). No differences were observed in resting metabolic rate, sleep quality, and subjective well-being, though endurance athletes demonstrated higher levels of vigorous physical activity than strength athletes (p = 0.014). Conclusions: In conclusion, we reveal a distinct physiological phenotype between strength, intermittent, and endurance athletes in terms of body composition, dietary intake, and physical activity levels. These findings underscore the necessity for tailored training and nutrition protocols depending on the sports discipline.

Assessment of Micro- and Macronutrient Intake in Male Competitive Athletes Using the Epic-Norfolk Food Frequency Questionnaire

This study aimed to investigate diet quality in a population of male competitive athletes by comparing their total energy and macro- and micronutrients intake assessed by a food frequency questionnaire (FFQ) to current nutritional recommendations for this specific population. An additional goal was to assess athletes' sodium-to-potassium (Na-to-K) ratio. This cross-sectional study involved 31 healthy competitive male athletes. Subjects' body mass index, body composition, arterial blood pressure, as well as red blood count (RBC) and serum lipid profile measurements showed that all subjects were lean and normotensive and had normal RBC and serum lipid levels. All subjects completed a cross-culturally adapted, translated, and validated EPIC-Norfolk FFQ. The total energy intake reported in the FFQ was below the recommended values; however, 71% of subjects were classified as low energy reporters (LERs). Energy intake from proteins was within and from carbohydrates was below the recommended interval, while the total energy intake from fats (and also saturated fatty acids) exceeded the recommendations. Suboptimal intakes of vitamin D and folate were observed, indicating the necessity for monitoring (and supplementing) in this population. High Na intake, which despite adequate K intake resulted in a higher Na-to-K ratio, highlighted concerns over excessive salt consumption, but also accentuated the need for monitoring sodium (and potassium) intake in competitive athletes with consideration for sweat-related losses.

The barriers and facilitators of improving energy availability amongst females clinically diagnosed with Relative Energy Deficiency in Sport (REDs)

BACKGROUND

Relative Energy Deficiency in Sport (REDs) is a serious clinical condition. However, there is little research in athletes with a clinical diagnosis and limited evidence on the recovery of REDs.

METHODS

This is a cross-sectional retrospective study whereby 55 (25.62±6.33 years) female patients with a prior diagnosis of REDs by an experienced medical specialist participated in an online questionnaire designed to capture their experience of a sports dietitian consultation and subsequent implementation of a personalized energy availability (EA) plan.

RESULTS

A 31% increase (N.=4 vs. N.=16, P=0.002) in normal menstruation, a 22% reduction (N.=39 vs. N.=27, P=0.032) in gastrointestinal symptoms, and a 94% reduction (N.=16 to N.=1) in a very poor/poor appetite were reported following the consultation and plan implementation. Required energy intake (EI) was under-estimated by 93% of participants. Intake pre-exercise was implemented most frequently (69%, N.=38), and least likely to elicit feelings of stress and anxiety (69%, N.=38). Weight gain/shape change was the most frequently reported barrier to implementation (62%, N.=34). Eating to a planned regime (35%, N.=19) and following a timing of intake (33%, N.=18) gave the most confidence.

CONCLUSIONS

Providing an athlete with an education of their current and required EA, alongside an illustrated personalized EI plan structured around exercise, may provide the "lightbulb" moment needed to overcome the associated anxiety when increasing their EI when recovering from REDs.

Impact of Acute Dietary and Exercise Manipulation on Next-Day RMR Measurements and DXA Body Composition Estimates

PURPOSE

The objective of this study is to investigate the effects of acute diet and exercise manipulation on resting metabolic rate (RMR) measurement variability and dual-energy x-ray absorptiometry (DXA) body composition estimates.

METHODS

Ten male and 10 female endurance athletes (12 cyclists, 5 triathletes, 4 runners) of tier 2 ( n = 18) to tier 3 ( n = 2) caliber underwent five conditions using a Latin square counterbalance design. For 24 h, athletes consumed a diet providing excessive energy availability (EA) (75 kcal⋅kg fat-free mass (FFM) -1 ) without exercise (GEA rest ), high-EA (45 kcal⋅kg FFM -1 ) without (HEA rest ) or with exercise (HEA ex ), or low-EA (15 kcal⋅kg FFM -1 ) without (LEA rest ) or with exercise (LEA ex ). Exercise involved two bouts of cycling (morning bout: 149 ± 34 min at 55% of maximal aerobic capacity (V̇O 2max ); afternoon bout: 60 min at 65% of V̇O 2max ) that resulted in a cumulative exercise energy expenditure of 30 kcal⋅kg FFM -1 . The following day, RMR and DXA measurements occurred after a 10-h fast and 12-h postexercise.

RESULTS

There were neither sex differences in relative RMR ( P = 0.158) nor effects of any of the five conditions on RMR ( P = 0.358). For both male and female athletes, FFM estimates were decreased following the LEA rest (-0.84 ± 0.66 kg; P = 0.001) and LEA ex (-0.65 ± 0.86 kg; P = 0.016) conditions compared with the GEA rest condition and following the LEA rest (-0.73 ± 0.51 kg; P = 0.001) and LEA ex (-0.54 ± 0.79 kg; P = 0.024) conditions compared with the HEA ex condition. There was no effect of condition on fat mass estimates ( P = 0.819).

CONCLUSIONS

Acute periods of diet and exercise manipulation did not create artifacts in next-day RMR measurements. However, as changes in estimates of FFM were seen, diet and exercise should be controlled in the 24-h before DXA scans.

The race within a race: Together on the marathon starting line but miles apart in the experience

Every four years the world's best athletes come together to compete in the Olympic games, electrifying audiences with incredible feats of speed, strength, endurance and skill as personal best performances and new records are set. However, the exceptional talent that underpin such performances is incomprehensible to most casual observers who often cannot appreciate how unique these athletes are. In this regard, endurance running, specifically the marathon, a 42.195 km foot race, provides one of the few occasions in sport outside of Olympic, world and national competitions, that permits sport scientists and fans alike to directly compare differences in the physiology between recreational and elite competitors. While these individuals may all cover the same distance, on the same course, on the same day - their experience and the physiological and psychological demands placed upon them are vastly different. There is, in effect, a "race within a race". In the current review we highlight the superior physiology of the elite endurance athlete, emphasizing the gap between elite competitors and well-trained, but less genetically endowed athletes. We draw attention to a range of inconsistencies in how current sports science practices are understood, implemented, and communicated in terms of the elite and not-so-elite endurance athlete.

Prospective study of food intake changes in adolescent elite athletes

Background

Inadequate energy intake among athletes can lead to low energy availability (LEA) which in turn can result in negative effects on athletic performance and physical and psychological health. This syndrome is known as relative energy deficiency in sports (REDs).

Objective

To map perceived changes in overall food intake among adolescent athletes during the previous year, as well as weekly changes during a 3-month period and to examine how these changes are associated with mental health, physical load and sex.

Methods

A total of 168 high school athletes from eight different sports participated. A baseline questionnaire examined changes in training habits and food intake in the past year, mental health (short version of the Warwick-Edinburgh Mental Well-being Scale (SWEMWBS)), injury history and previous periods of poor psychological health. Weekly digital questionnaires for 3 months tracked weekly physical and mental load and changes in food intake. Comparative and correlation analyses were performed with p<0.05 considered significant.

Results

A decreased food intake during the previous year was reported more often among athletes experiencing periods of poor mental health than those without such periods (10% vs 2%; p=0.034). Athletes who decreased their food intake reported lower mental well-being than athletes who increased their food intake (mean difference in SWEMWBS=4.69±1.57; p=0.021). Over a 3-month period, most athletes did not change their food intake, yet fluctuations in physical load were reported.

Conclusion

This study showed that athletes experiencing lower mental health or period(s) of poor mental health reported decreased food intake more often than those with better mental health or those without period(s) of poor mental health. In addition, the mismatch found between perceived weekly changes in overall food intake and changes in physical load during the same time period could potentially result in an increased risk for LEA.

Sex and gender in sports nutrition research: bridging the gap

The Olympic Games have grown to be the largest, gender-equal sporting event in the world, and the International Olympic Committee is committed to gender equality in sports encouraging and supporting the promotion of women in sports at all levels and in all structures with a view to implementing the principle of equality of men and women (IOC, 2023). Women competed for the first time at the 1900 Olympic Games in Paris, and the number of women competing has grown exponentially over the last 100 years, so an estimated 5494 female athletes (48 %) competed in the Summer Olympic Games 2021 in Tokyo. Supporting women (alongside men) in achieving optimum performance is crucial, and understanding that there are sex and gender gaps in sports nutrition research is important. One reason for this gap is the historical bias in sports and exercise science research towards male participants. This has led to a poor understanding of the unique physiological and nutritional needs of female athletes. In summary, a balanced approach is crucial to address the nutritional needs of both male and female athletes. Researchers should continue exploring this important area to optimise performance and health for all athletes. The aim of this review is to summarise current sports nutrition literature and highlight research that seeks to understand and address where the gaps are with respect to several key areas in sports nutrition recommendations that can impact advice and practice with both males and females.

Interrelationships between stress, eating attitudes, and metabolism in endurance athletes across a competitive season

A competitive sport season represents a multidimensional stressor where physical and psychological stress may render an athlete susceptible to energy deficiency (ED). Downstream effects of ED can include a reduction in measured-to-predicted resting metabolic rate (RMRratio), indicating metabolic compensation. A pathway linking stress, eating attitudes, and metabolic compensation has not been explored. To test if sport-specific stress is associated with eating attitudes and metabolism in endurance athletes (18-22 years) at different phases of a competitive season, we assessed two groups of athletes: 26 swimmers (15 female and 11 male) during peak season (PEAK), and 26 runners (female) across pre- (PRE) and off-season (OFF). Stress (RESTQ-52), eating attitudes (cognitive restraint (CR), drive for muscularity (DM), and body dissatisfaction), and metabolism (RMRratio) were assessed. In PRE, sport-specific stress and CR were negatively correlated with RMRratio (R = -0.58; p < 0.05, and R = -0.57; p < 0.05, respectively). In PEAK, sport-specific stress and DM were negatively correlated with RMRratio (R = -0.64; p < 0.05; R = -0.40; p < 0.05, respectively). DM was positively related to sport-specific stress (R = 0.55; p < 0.05). During OFF, there was no relation between RMRratio and sport-specific stress. In runners, there was a change in stress from PRE-to-OFF with highest reported stress during PRE (p < 0.05) versus OFF. Regression analyses revealed that sport-specific stress and CR were significant predictors of RMRratio during PRE and PEAK (p < 0.05), but not OFF (p > 0.05). Associations between stress, eating attitudes, and metabolic compensation in endurance athletes during PRE and PEAK season suggest that during heavier training, metabolic compensation may be linked to upstream eating attitudes associated with sport-stressors.

Measurement of energy availability in highly trained male endurance athletes and examination of its associations with bone health and endocrine function

PURPOSE

Despite the introduction of Relative Energy Deficiency in Sport (RED-s) in 2014, there is evidence to suggest that male endurance athletes still present with a high prevalence of low energy availability (LEA). Previous findings suggest that energy availability (EA) status is strongly correlated with impairments in endocrine function such as reduced leptin, triiodothyronine (T3), and insulin, and elevated bone loss. This study aimed to report the current EA status, endocrine function and bone health of highly trained Irish male endurance athletes.

METHODS

In this cross-sectional study, participants (n = 3 triathletes; n = 10 runners) completed a 7-day testing period during the competition season using lab-based measures, to ascertain EA status, hormone level and rates of bone metabolism. Serum blood samples were obtained to assess hormone levels and markers of bone metabolism.

RESULTS

Mean EA was < 30 kcal/kg lean body mass (LBM)/day in 76.9% of athletes. There was a strong association between LEA and low carbohydrate intake, and lower LBM. Mean levels of insulin, IGF-1 and leptin were significantly lower than their reference ranges. Elevated mean concentrations of β-CTX and a mean P1NP: β-CTX ratio < 100, indicated a state of bone resorption.

CONCLUSION

The EA level, carbohydrate intake, hormone status and bone metabolism status of highly trained male endurance athletes are a concern. Based on the findings of this study, more frequent assessment of EA across a season is recommended to monitor the status of male endurance athletes, in conjunction with nutritional education specific to EA and the associated risks.

The habitual degree of weight loss might be associated with specific fat and protein intakes during a period of weight maintenance in athletes used to weight variations: preliminary results from the WAVE study

Weight variations are common in sporting life, with important inter-individual variability in the degree of an athlete's habitual weight loss. As a part of the WAVE study (NCT04107545), the main objective of this preliminary study was to determine whether the habitual degree of weight loss was associated with anthropometric, body composition, nutritional or psychometric profiles during a period of weight maintenance in athletes accustomed to weight variations. We hypothesized that athletes accustomed to a higher habitual degree of weight loss may have a higher body weight and body fat mass, and may present a more controlled diet regimen and cognitive restriction than athletes with a lower habitual degree of weight loss. During a period of weight maintenance, 62 athletes (24.0 ± 5.3 years; 26 women) completed anthropometry and body composition measurements, a 48-hours food diary and self-reported questionnaires to determine their weight variation practice, nutritional profile and mood state. Athletes were stratified within inter- and intra-quartile groups according to their habitual degree of weight loss. Athletes with a higher habitual degree of weight loss were those who consumed more protein (P < .001) and less fat (P = .01) as a proportion of total energy compared with those losing less weight, without any difference in body composition between the groups. The rapid weight loss score was significantly higher in individuals losing more weight (P < .001) and no difference was observed for the mood state profile. The present results suggest a potential control of nutritional regulation during a period of weight maintenance in order to spare fat-free mass and favor fat mass loss in athletes who are routinely losing more weight. Fat-free mass may be the main nutritional driver due to low body fat mass in athletes, which may limit the "catch-up fat" phenomenon commonly observed in nonathletic population.

Risk for low energy availability, disordered eating and sleep disturbance among female football players

PURPOSE

Low energy availability (LEA) and mental health issues are prevalent among female athletes and can have adverse effects on health and sports performance. This study aimed to assess energy availability and, mental health status (depression, anxiety, sleep deprivation, drug misuse, alcohol misuse, and disordered eating) among female football players. Despite the availability of validated tools for the triads and REDs, few studies have focused on the prevalence of LEA and mental health in female football players. Furthermore, limited information is available on LEA and its consequences in India.

METHODS

Professional female football players (n=25) aged 19-30 years were recruited using incidental sampling. LEA was estimated based on energy availability [energy intake - activity energy expenditure] and LEA female questionnaire (LEAF-Q). Sports mental health assessment tool-1 (SMHAT-1) was used to assess the mental health status. Descriptive statistics and chi square test were used to test the hypotheses.

RESULTS

According to the factorial method and LEAF-Q, 24% and 12% of players had LEA, respectively. LEA symptoms, such as decreased gastrointestinal and menstrual function, were observed in 16% of participants, while 8% had a history of injury. 44% of the participants exhibited poor mental health. Sleep disturbance (12%) and disordered eating (44%), were among the most common mental health issues. No significant difference was found between LEA, disordered eating, and sleep disturbance.

CONCLUSION

Female football players were more likely to develop LEA and mental health disorders, such as disordered eating and sleep disturbance. LEA was not linked with disordered eating or sleep disturbance. Early detection of LEA and effective intervention enhances the health and performance of female football players.

Food choice, activity level, and carbon footprint: exploring potential for sustainable food consumption practices in young adults

This study aims to explore climate consciousness in relation to food consumption in young adults, examining its relationship with physical activity level and gender. A mixed-method approach is utilized, integrating seven-day food records and semi-structured interviews, employing social practice theory in our analytical framework. Our cohort of 47 participants (25 women, 22 men) displays varied diets, from omnivores to vegans. Moderately-active women show the lowest carbon footprint, favoring climate-conscious choices related to lower energy needs and plant-based preferences. Highly-active individuals consume more energy, resulting in a higher carbon footprint. Gender differences are evident, women were inclined to climate-conscious food practices motivated by animal ethics and health concerns. Conversely, men demonstrated a tendency for meat consumption. Participants share an understanding of carbon footprint, reflecting a solid awareness of food-related climate impact but differ in priorities; performance for highly-active, and economy for moderately-active. This highlights a mix of commonalities and distinctions, informing flexible, sustainable food practices. Higher activity levels are linked to greater energy needs and a higher carbon footprint. Moderately-active women show the most climate-conscious food choices, leading to the lowest carbon footprint. Our findings indicate that highly-active individuals and men have significant potential to improve climate-adapted food consumption.

Energy expenditure, intake and availability in female soccer players via doubly labelled water: Are we misrepresenting low energy availability?

Female soccer players have been identified as presenting with low energy availability (LEA), though the prevalence of LEA may be overestimated given inaccuracies associated with self-reporting dietary intakes. Accordingly, we aimed to quantify total daily energy expenditure (TDEE) via the doubly labelled water (DLW) method, energy intake (EI) and energy availability (EA). Adolescent female soccer players (n = 45; 16 ± 1 years) completed a 9-10 day 'training camp' representing their national team. Absolute and relative TDEE was 2683 ± 324 and 60 ± 7 kcal kg-1 fat free mass (FFM), respectively. Mean daily EI was lower (P < 0.01) when players self-reported using the remote food photography method (RFPM) (2047 ± 383 kcal day-1) over a 3-day period versus DLW derived EI estimates accounting for body mass (BM) changes (2545 ± 518 kcal day-1) over 7-8 days, representing a mean daily Δ of 499 ± 526 kcal day-1 and 22% error when using the RFPM. Estimated EA was different (P < 0.01) between methods (DLW: 48 ± 14 kcal kg-1 FFM, range: 22-82; RFPM: 37 ± 8 kcal kg-1 FFM, range: 22-54), such that prevalence of LEA (<30 kcal kg-1 FFM) was lower in DLW compared with RFPM (5% vs. 15%, respectively). Data demonstrate the potential to significantly underestimate EI when using self-report methods. This approach can therefore cause a misrepresentation and an over-prevalence of LEA, which is the underlying aetiology of 'relative energy deficiency in sport' (REDs). HIGHLIGHTS: What is the central question of this study? Do self-reported dietary intakes (via remote food photography method, RFPM) overestimate low energy availability (LEA) prevalence in female soccer players compared with energy intake evaluation from the doubly labelled water (DLW) method? What is the main finding and its importance? Estimated energy availability is greater with the DLW method compared with RFPM, such that the prevalence of LEA is greater when self-reporting dietary intakes. Accordingly, data demonstrate the potential to misrepresent the prevalence of LEA, an underlying factor in the aetiology of 'relative energy deficiency in sport' (REDs).

Twenty four-hour passive heat and cold exposures did not modify energy intake and appetite but strongly modify food reward

Effects of acute thermal exposures on appetite appear hypothetical in reason of very heterogeneous methodologies. The aim of this study was therefore to clearly define the effects of passive 24-h cold (16°C) and heat (32°C) exposures on appetitive responses compared with a thermoneutral condition (24°C). Twenty-three healthy, young and active male participants realised three sessions (from 13.00) in a laboratory conceived like an apartment dressed with the same outfit (Clo = 1). Three meals composed of three or four cold or warm dishes were served ad libitum to assess energy intake (EI). Leeds Food Preference Questionnaires were used before each meal to assess food reward. Subjective appetite was regularly assessed, and levels of appetitive hormones (acylated ghrelin, glucagon-like peptite-1, leptin and peptide YY) were assessed before and after the last meal (lunch). Contrary to the literature, total EI was not modified by cold or heat exposure (P = 0·120). Accordingly, hunger scores (P = 0·554) were not altered. Levels of acylated ghrelin and leptin were marginally higher during the 16 (P = 0·032) and 32°C (P < 0·023) sessions, respectively. Interestingly, implicit wanting for cold and low-fat foods at 32°C and for warm and high-fat foods at 16°C were increased during the whole exposure (P < 0·024). Moreover, cold entrées were more consumed at 32°C (P < 0·062) and warm main dishes more consumed at 16°C (P < 0·025). Thus, passive cold and hot exposures had limited effects on appetite, and it seems that offering some choice based on food temperature may help individuals to express their specific food preferences and maintain EI.

The Prevalence of Low Energy Availability in Cross-Country Skiers during the Annual Cycle

BACKGROUND AND OBJECTIVES

A sustained mismatch between energy intake (EI) and exercise energy expenditure (EEE) can lead to Low Energy Availability (LEA), as well as health and performance impairments characteristic of Relative Energy Deficiency in Sport (RED-S). Research in females has identified specific LEA cut-points for the risks of developing physiological and performance disturbances. Cut-points in males have yet to be evaluated; therefore, this study examined the prevalence of LEA in highly trained male cross-country skiers. The key purpose of this study was to analyze EI, resting energy expenditure (REE), EEE, and energy availability (EA) in highly trained cross-country skiers during the preparation and competition periods. The secondary objective of our study was to evaluate the relative contribution of fats and carbohydrates to EI, REE, and EEE.

MATERIALS AND METHODS

EI was determined by an estimated 24 h diet recall method, REE was assessed by indirect calorimetry, and EEE was estimated from heart rate in 27 cross-country skiers.

RESULTS

EI amounted to 4050 ± 797 kcal/day on a typical training day (TD) and 5986 ± 924 kcal/day (p < 0.001) on a typical competition day (CD). REE on TDs (2111 ± 294 kcal/day or 30 ± 6 kcal/day/kg) was higher (p < 0.05) than on CDs (1891 ± 504 kcal/day or 27 ± 7 kcal/day/kg). The EA in the athletes was <15 kcal∙kg FFM-1·d-1 on TDs and <65 kcal∙kg FFM-1·d-1 on CDs. EI was not optimal, as indicated by low EA throughout TDs (June). This could be associated with insufficient EI along with a high amount of EEE (3690.7 ± 485.2 kcal/day). During the transition from TD to CD, an increase in the contribution of fats to EI and EEE was observed in cross-country skiers.

CONCLUSION

The conception of LEA and REDs and their potential implication for performance is underestimated among coaches and athletes. The importance of appropriate dietary strategies is essential to ensure that enough calories are consumed to support efficient training.

Body Composition and Energy Expenditure in Youth With Spina Bifida: Protocol for a Multisite, Cross-Sectional Study

BACKGROUND

Obesity prevalence in youth with spina bifida is higher than in their typically developing peers. Obesity is associated with lifelong medical, psychological, and economic burdens. Successful prevention or treatment of obesity in individuals with spina bifida is compromised by (1) the lack of valid and reliable methods to identify body fat in a clinical setting and (2) limited data on energy expenditure that are necessary to provide daily caloric recommendations.

OBJECTIVE

The objectives of this study will be to develop 2 algorithms for use in youth with spina bifida in a clinical setting, one to model body fat and one to predict total daily energy expenditure. In addition, physical activity and dietary intake will be described for the sample.

METHODS

This multisite, prospective, national clinical study will enroll 232 youth with myelomeningocele aged 5 to 18 years (stratified by age and mobility). Participants will be enrolled for 1 week. Data obtained include 4 measures of body composition, up to 5 height measures, a ramped activity protocol, and a nutrition and physical activity screener. Participants will wear an accelerometer for the week. On the final study day, 2 samples of urine or saliva, which complete the doubly labeled water protocol, will be obtained. The analysis will include descriptive statistics, Bland-Altman plots, concordance correlation, and regression analysis.

RESULTS

The study received extramural federal funding in July 2019. Data collection was initiated in March 2020. As of April 2024, a total of 143 (female participants: n=76, 53.1%; male participants: n=67, 46.9%) out of 232 participants have been enrolled. Data collection is expected to continue throughout 2024. A no-cost extension until November 2025 will be requested for data analysis and dissemination of findings.

CONCLUSIONS

This study furthers previous pilot work that confirmed the acceptability and feasibility of obtaining alternate height, body composition, and energy expenditure measures. The findings from this study will enhance screening, prevention, and treatment of abnormal weight status by facilitating the accurate identification of youths' weight status category and recommendations of daily caloric needs for this population that is at higher risk of obesity. Furthermore, the findings have the potential to impact outcomes for youth diagnosed with disabilities other than spina bifida who experience similar challenges related to alterations in body composition or fat distribution or measurement challenges secondary to mobility issues or musculoskeletal problems.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/52779.

Running Event, Age, and Competitive Level as Predictors of Dual-Energy X-Ray Absorptiometry-Derived Body Composition and Bone Health Markers in Female Runners

ABSTRACT

Wilson, LJ and Curtis, C. Running event, age, and competitive level as predictors of dual-energy X-ray absorptiometry-derived body composition and bone health markers in female runners. J Strength Cond Res 38(7): e366-e372, 2024-The aim of this study was to assess the impact of running discipline, competitive level (COMP), and age on body composition measures in female athletes. A total of n = 51 female runners (age: 30.9 ± 5.7 years, stature: 166.7 ± 5.7 cm, and body mass (BM): 57.1 ± 8.2 kg) completed a full-body dual-energy x-ray absorptiometry (DXA) scan in a cross-sectional design. One-way ANOVA or Kruskal-Wallis was used to identify differences in DXA measures and independent variables. Stepwise regression determined the contribution of independent variables on DXA measures. Body fat percentage (BF%) and fat mass (FM) differed based on COMP (BF%: H (2) = 17.451; FM: H (2) = 17.406, both p ≤ 0.0001). Competitive level modestly predicted BF% and FM (BF%: R2adj = 0.316, F (1,50) = 22.660; FM: R2adj = 0.300, F (1,50) = 21.029, both p ≤ 0.0001). Bone mineral density (BMD) and BMD Z-score (BMD Z ) did not differ between age, running discipline, or COMP (age: BMD: F (2,50) = 2.825, BMD Z : F (2,50) = 2.215; running discipline: BMD: F (3,50) = 1.145, BMD Z : F (3,50) = 1.474; COMP: BMD: F (2,50) = 0.074, BMD Z : F (2,50) = 1.297, all p ≤ 0.05). Age and running discipline modestly predicted BMD and BMD Z (BMD: R2adj = 0.179, F (1,50) = 5.264; BMD Z : R2adj = 0.173, F (1,50) = 4.545, both p ≤ 0.05). These findings indicate COMP may be a predictor of BF% and FM. Age and running discipline appear predictors of bone health markers. Such findings may enable medical and sport science practitioners to tailor interventions relating to realization of training adaptations, performance, and health.

Weight Gain in Midlife Women

PURPOSE OF REVIEW

To summarize the evidence and clinical implications of weight and body composition changes during midlife in women and provide an overview of weight gain prevention and management in this population.

RECENT FINDINGS

Aging-related changes such as decreased energy expenditure and physical activity are important culprits for weight gain in midlife women. The hormonal changes of menopause also influence body adiposity distribution and increase central adiposity. These body changes can have health consequences including the development of cardiometabolic diseases, osteoarthritis, cancer, worsening in cognition, mental health, and menopause symptoms. Midlife women experience changes related to aging, menopause, and lifestyle which favor weight gain. Clinical practice should focus on early counseling and anticipatory guidance on the importance of dietary changes and physical activity to attenuate this phenomenon. Future research should focus on the longitudinal relationship between weight trends in midlife and health consequences and mortality.

Low Energy Availability Followed by Optimal Energy Availability Does Not Benefit Performance in Trained Females

PURPOSE

Short periods of reduced energy availability are commonly undertaken by athletes to decrease body mass, possibly improve the power-to-mass ratio, and enhance physical performance. Our primary aim was to investigate the impact of 10 d of low energy availability (LEA) followed by 2 d of optimal energy availability (OEA) on physical performance parameters in trained females. Second, physiological markers at the whole-body and molecular level related to performance were evaluated.

METHODS

Thirty young trained eumenorrheic females were matched in pairs based on training history and randomized to a 10-d intervention period of LEA (25 kcal·fat-free mass (FFM) -1 ·d -1 ) or OEA (50 kcal·FFM -1 ·d -1 ) along with supervised exercise training. Before the intervention, participants underwent a 5-d run-in period with OEA + supervised exercise training. After the LEA intervention, 2 d of recovery with OEA was completed. Participants underwent muscle biopsies, blood sampling, physical performance tests, body composition measurements, and resting metabolic rate measurements. A linear mixed model was used with group and time as fixed effects and subject as random effects.

RESULTS

Compared with OEA, LEA resulted in reduced body mass, muscle glycogen content, repeated sprint ability, 4-min time-trial performance, and rate of force development of the knee extensors (absolute values; P < 0.05). Two days of recovery restored 4-min time-trial performance and partly restored repeated sprint ability, but performance remained inferior to the OEA group. When the performance data were expressed relative to body mass, LEA did not enhance performance.

CONCLUSIONS

Ten days of LEA resulted in impaired performance (absolute values), with concomitant reductions in muscle glycogen. Two days of recovery with OEA partially restored these impairments, although physical performance (absolute values) was still inferior to being in OEA. Our findings do not support the thesis that LEA giving rise to small reductions in body mass improves the power-to-mass ratio and thus increases physical performance.

Off- to in-season body composition adaptations in elite male and female endurance and power event athletics competitors: an observational study

BACKGROUND

Monitoring elite athletes' body composition (BC) is vital for health and optimizing performance in sports emphasizing leanness, such as athletics. This study aims to investigate and compare sex- and event-specific off-to in-season BC changes in endurance and power event athletics competitors.

METHODS

Elite male and female endurance athletes (> 800 m runners; n = 21) and power event athletes (sprinters, jumpers; n = 32) underwent dual-energy X-ray absorptiometry (DXA) scans for whole and regional lean mass (LM), fat mass (FM), bone mineral content (BMC), and density (BMD) during off-season (September-October) and in-season (April-May). Linear mixed models tested between-group off-season differences in BC, within-group off-season to in-season changes, and between-group differences in change. To assess meaningful or least significant changes (LSC) in BC, DXA precision errors were determined from two consecutive total body scans in a subsample of athletes (n = 30).

RESULTS

Male athletes (n = 26) gained significantly (p < 0.05) more body mass (BM; mean difference 1.5 [95% confidence interval (CI):0.5-2.4] kg), LM (843 [95% CI:-253:1459] g), and trunk LM (756 [-502:1156] g) than female athletes (n = 27). The proportion of changes in athlete's BC exceeding the LSC threshold for LM and trunk LM were 70% and 65% in males, and 48% and 26% in females. Significant (p < 0.05) within-group off-season to in-season increases in LM were found for male endurance and power athletes, and female power athletes. All groups significantly increased BMD (p < 0.05). Only male and female power athletes had significant in- to-off-season increases in BMC. 80% of all athletes who had a meaningful increase in BMC belonged to the power event group. No significant within- or between group change in FM was observed.

CONCLUSIONS

The present study found that male athletes gained more BM, LM and trunk LM than females. Within-group increases in regional and whole-body LM and BMC were predominantly found among power event competitors. Incorporating individual meaningful changes alongside traditional statistics provided additional insights into sex and event-group differences. Future research on elite athletic event groups should include DXA measurements closer to major outdoor-season competitions, coupled with site-specific measures (ultrasound, MRI) for better detection of subtle changes in LM and FM.

Evolutionary Echoes: A Four-Day Fasting and Low-Caloric Intake Study on Autonomic Modulation and Physiological Adaptations in Humans

This study evaluates the psychophysiological response to a simulated hunter-gatherer endurance task with restricted caloric intake over four days. It assesses changes in body composition, autonomic modulation, and physical and cognitive performance. Participants underwent daily 8 h fasted walks followed by a 150 kcal meal to replicate hunter-gatherer activity and dietary patterns. Measurements of metabolic, respiratory, and subjective well-being, along with heart rate variability (HRV) monitoring, were conducted pre- and post-activity to evaluate the impact of endurance activity under caloric restriction. We found weight loss, decreased body and visceral fat, and reduced skeletal muscle mass and water percentage. High sympathetic activation and stable urinary markers, except for increased proteinuria, indicated stress responses and muscular degradation. Elevated perceived exertion post-exercise with good adaptation to prolonged effort underlines the body's adaptability to ancestral lifestyle conditions, highlighting the connection among endurance, nutrition, and psychophysiological health.

The Importance of Dietary Protein Quality in Mid- to High-Income Countries

In wealthy countries, the protein intake of adults is usually considered to be adequate, and considerations of protein quality are often deemed irrelevant. The objective was to examine dietary protein intakes of adults in developed countries in the context of dietary protein quality. An analysis of NHANES population data on actual protein intakes in the United States (a developed country) demonstrated that for a dietary Digestible Indispensable Amino Acid Score (DIAAS) of 100%, 11% of the adult (19-50 y) population had habitual protein intakes below the Estimated Average Requirement (EAR) and 22% below the Recommended Dietary Allowance. The percentage of the population with utilizable protein intakes potentially falling below the EAR increased as the assumed DIAAS declined. Analysis of the NHANES data and several other datasets also indicated that total protein intakes can be limiting or close to limiting for the elderly and some vegetarians and vegans. Here, lower dietary protein quality can potentially lead to inadequate utilizable protein intakes. For many people in specific physiological states (e.g., weight loss, endurance sports, resistance exercise) attempting to meet higher dietary protein targets often with accompanying lowered energy intakes, low dietary protein quality can lead to protein calories expressed as a proportion of total calories, falling outside what may be acceptable limits (maximum of 30% protein calories from total calories). In general, individuals within the adult population may be susceptible to macronutrient imbalance (whenever total protein intakes are high, daily energy intakes low) and for diets with lower protein quality (DIAAS <100%). Our analysis shows that dietary protein quality is relevant in mid- to high-income countries.

Body composition assessment in a large cohort of Olympic athletes with different training loads: possible reference values for fat mass and fat-free mass domains

AIMS

To assess body composition by means of BOD POD in the large cohort of Italian Olympic athletes of many sport disciplines (studied at the same time), and to provide possible reference values for body composition in elite athletes.

METHODS

1556 elite athletes, who took part in the selection procedure for the 2016 Rio Olympic Games for the National Italian Olympic Committee (CONI), were retrospectively studied. Body composition was determined using air plethysmography-based BOD POD.

RESULTS

We observed that Fat Mass (FM) and Fat-free Mass (FFM) should be considered as two mutually independent domains in elite athletes. By performing Principal Component Analysis, we defined two independent main domains (respectively, representing FM and FFM), which presented different trends according to gender and static or dynamic exercise load. Lastly, we reported possible reference values for FM index and FFM index, respectively, representing the largest contributors to FM domain and FFM domain, and calculated as FM or FFM (kg)/height (m2).

CONCLUSIONS

Our findings might provide a basis to optimize the practical approach to body composition in athletes, highlighting the importance of considering indicators of fat mass and lean mass "simultaneously" and not specularly, according to different sport disciplines as well. Moreover, these data might contribute to standardize reference values for body composition in elite athletes, with a view to potentially helping to monitor and guide training regimens, prevent related detrimental practices and plan cardiometabolic prevention and rehabilitation programs.

Advances in Understanding the Interplay between Dietary Practices, Body Composition, and Sports Performance in Athletes

The dietary practices of athletes play a crucial role in shaping their body composition, influencing sports performance, training adaptations, and overall health. However, despite the widely acknowledged significance of dietary intake in athletic success, there exists a gap in our understanding of the intricate relationships between nutrition, body composition, and performance. Furthermore, emerging evidence suggests that many athletes fail to adopt optimal nutritional practices, which can impede their potential achievements. In response, this Special Issue seeks to gather research papers that delve into athletes' dietary practices and their potential impacts on body composition and sports performance. Additionally, studies focusing on interventions aimed at optimizing dietary habits are encouraged. This paper outlines the key aspects and points that will be developed in the ensuing articles of this Special Issue.

Characteristics of non-exercise activity thermogenesis in male collegiate athletes under real-life conditions

Athletes experience high total energy expenditure; therefore, it is important to understand the characteristics of the components contributing to this expenditure. To date, few studies have examined particularly the volume and activity intensity of non-exercise activity thermogenesis (NEAT) in athletes compared to non-athletes under real-life conditions. This study aimed to determine the volume and intensity of NEAT in collegiate athletes. Highly trained Japanese male collegiate athletes (n = 21) and healthy sedentary male students (n = 12) participated in this study. All measurements were obtained during the athletes' regular training season under real-life conditions. NEAT was calculated using metabolic equivalent (MET) data using an accelerometer. The participants were asked to wear a validated triaxial accelerometer for 7 consecutive days. Physical activity intensity in NEAT was classified into sedentary (1.0-1.5 METs), light (1.6-2.9 METs), moderate (3.0-5.9 METs), and vigorous (≥6 METs) intensity. NEAT was significantly higher in athletes than in non-athletes (821 ± 185 kcal/day vs. 643 ± 164 kcal/day, p = 0.009). Although there was no significant difference in NEAT values relative to body weight (BW) between the groups (athletes: 10.5 ± 1.7 kcal/kg BW/day, non-athletes: 10.4 ± 2.2 kcal/kg BW/day, p = 0.939), NEAT to BW per hour was significantly higher in athletes than in non-athletes (0.81 ± 0.16 kcal/kg BW/h vs. 0.66 ± 0.12 kcal/kg BW/h, p = 0.013). Athletes spent less time in sedentary and light-intensity activities and more time in vigorous-intensity activities than non-athletes (p < 0.001, p = 0.019, and p = 0.030, respectively). Athletes expended more energy on vigorous- and moderate-intensity activities than non-athletes (p = 0.009 and p = 0.011, respectively). This study suggests that athletes' NEAT relative to BW per day is similar to that of non-athletes, but athletes spend less time on NEAT, which makes them more active in their daily lives when not exercising and sleeping.

Fat-Free Mass Index in a Large Sample of National Collegiate Athletic Association Men and Women Athletes From a Variety of Sports

ABSTRACT

Magee, MK, Fields, JB, Jagim, AR, and Jones, MT. Fat-free mass index in a large sample of National Collegiate Athletic Association men and women athletes from a variety of sports. J Strength Cond Res 38(2): 311-317, 2024-Fat-free mass index (FFMI) can be used to categorize fat-free mass (FFM) relative to height. Normative values have been established in a variety of sports, as has suggested lower and upper thresholds of FFMI. However, FFMI has not been reported in a large sample of athletes, representing both sexes and multiple sport types. The purpose of this study was to evaluate differences in FFMI and establish normative values across a large sample of collegiate sports. A total of 1,961 athletes (men: n = 596, 10 sports; women: n = 1,365, 8 sports) participated. Height and mass were measured using a stadiometer and calibrated digital scale, respectively. Fat-free mass was assessed with air displacement plethysmography and used to calculate FFMI. Kruskal-Wallis test and one-way analysis of variance evaluated differences in FFMI in women's and men's sports, respectively. When collapsed across sport type and stratified by sex, men had a higher FFMI (21.5 ± 1.9 kg·m -2 vs. 17.9 ± 1.8 kg·m -2 ; p < 0.001). Differences occurred in FFMI across sport. In women, basketball athletes had the highest FFMI (18.9 kg·m -2 ) and highest 99th percentile for FFMI, whereas rowers had the lowest (16.9 kg·m -2 ). In men, throwers had the highest FFMI (25.7 kg·m -2 ) and highest 99th percentile, whereas volleyball athletes had the lowest (19.9 kg·m -2 ). Differences in FFMI may be attributable to dietary habits and physiological demands of respective sports. These results can provide information relative to differences in FFMI values across sports. In addition, sport-specific normative values can be used as benchmarks and targets for training, nutrition, and goal setting.

Peak Week Carbohydrate Manipulation Practices in Physique Athletes: A Narrative Review

BACKGROUND

Physique athletes are ranked by a panel of judges against the judging criteria of the corresponding division. To enhance on-stage presentation and performance, competitors in certain categories (i.e. bodybuilding and classic physique) achieve extreme muscle size and definition aided by implementing acute "peaking protocols" in the days before competition. Such practices can involve manipulating nutrition and training variables to increase intramuscular glycogen and water while minimising the thickness of the subcutaneous layer. Carbohydrate manipulation is a prevalent strategy utilised to plausibly induce muscle glycogen supercompensation and subsequently increase muscle size. The relationship between carbohydrate intake and muscle glycogen saturation was first examined in endurance event performance and similar strategies have been adopted by physique athletes despite the distinct physiological dissimilarities and aims between the sports.

OBJECTIVES

The aim of this narrative review is to (1) critically examine and appraise the existing scientific literature relating to carbohydrate manipulation practices in physique athletes prior to competition; (2) identify research gaps and provide direction for future studies; and (3) provide broad practical applications based on the findings and physiological reasoning for coaches and competitors.

FINDINGS

The findings of this review indicate that carbohydrate manipulation practices are prevalent amongst physique athletes despite a paucity of experimental evidence demonstrating the efficacy of such strategies on physique performance. Competitors have also been observed to manipulate water and electrolytes in conjunction with carbohydrate predicated on speculative physiological mechanisms which may be detrimental for performance.

CONCLUSIONS

Further experimental evidence which closely replicates the nutritional and training practices of physique athletes during peak week is required to make conclusions on the efficacy of carbohydrate manipulation strategies. Quasi-experimental designs may be a feasible alternative to randomised controlled trials to examine such strategies due to the difficulty in recruiting the population of interest. Finally, we recommend that coaches and competitors manipulate as few variables as possible, and experiment with different magnitudes of carbohydrate loads in advance of competition if implementing a peaking strategy.

Current Perspectives: Obesity and Neurodegeneration - Links and Risks

Obesity is increasing in prevalence across all age groups. Long-term obesity can lead to the development of metabolic and cardiovascular diseases through its effects on adipose, skeletal muscle, and liver tissue. Pathological mechanisms associated with obesity include immune response and inflammation as well as oxidative stress and consequent endothelial and mitochondrial dysfunction. Recent evidence links obesity to diminished brain health and neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD). Both AD and PD are associated with insulin resistance, an underlying syndrome of obesity. Despite these links, causative mechanism(s) resulting in neurodegenerative disease remain unclear. This review discusses relationships between obesity, AD, and PD, including clinical and preclinical findings. The review then briefly explores nonpharmacological directions for intervention.

Nutritional knowledge, attitude, and practice of professional athletes in an Iranian population (a cross-sectional study)

BACKGROUND

Proper nutrition is vital in promoting community health, yet insufficient knowledge and improper dietary practices can lead to deficiencies and diseases. Professional athletes depend on optimal nutrition for their performance and recovery, but a lack of understanding can impede their potential. The nutritional status of athletes impacts their overall health and sports performance. Inadequate sports nutrition knowledge may result in suboptimal practices, reducing strength, power, endurance, and immunity. Additionally, disordered attitudes can lead to dietary imbalances and an increased risk of injury. This study, conducted in Qazvin, Iran, examined athletes' nutritional knowledge, attitudes, and practices. By addressing these factors, there is potential to enhance dietary behaviors and ultimately improve athletes' performance.

METHODS

The study employed a descriptive-analytical, cross-sectional design to investigate the nutritional knowledge, attitude, and practice (KAP) of professional athletes in Qazvin, Iran. A total of 320 purposefully selected professional athletes (68.13% male, 31.87% female) from various sports fields participated in the research. The data collection tool consisted of demographic questions and a KAP questionnaire, including 27 nutritional knowledge questions, 16 nutritional attitude questions, and 14 nutritional performance questions. The quota sampling method was used to estimate sample sizes. Data analysis was carried out by SPSS v.26 using one sample t-test, one-way ANOVA, and Pearson's correlation coefficient test.

RESULTS

The results showed that nutritional knowledge (the mean value was 79.594 ± 7.015 - the optimal knowledge level = 84) and attitude (the mean value was 23.347 ± 5.300 - the optimal attitude level = 26) for athletes are low, but their nutritional practice (the mean value was 21.788 ± 3.450 - the optimal performance level = 24) was moderate. Also, professional athletes' nutritional knowledge, attitude, and practice were lower than normal (p < 0.05). Significant positive correlations were among knowledge, attitude, and practice (p < 0.05). However, there were no significant differences in nutritional knowledge, attitude, and practice among the subjects of different age groups, genders, and sports types (p > 0.05).

CONCLUSION

This study showed that the nutritional knowledge, attitude, and practice of professional Iranian athletes in Qazvin province were low; therefore, the implementation of more theoretical and applied nutrition education, such as using knowledge assessment tools and interventions, irrespective of their age, sport's field, and gender, is compelling.

Nutritional intake in high-performance para athletes

OBJECTIVE

This study aimed to describe the eating habits of para-athletes who attended a specialized training center in Brazil.

METHODS

Participants were recruited from the Sports Training Center at the Universidade Federal de Minas Gerais, Brazil. Energy, macronutrient (expressed in absolute terms and relative to body weight), fiber, cholesterol, and micronutrient intakes were assessed via a food frequency questionnaire, based on intakes over the preceding 12 mo. Sociodemographic factors were assessed using a purpose-designed survey, which included self-reported weight and height. Differences in nutrient intake based on sex, age, body mass index, and sporting factors were evaluated.

RESULTS

A total of 30 para-athletes (in para athletics, para-powerlifting, para-swimming, and para-taekwondo) were included in the study. The median total energy intake was 4089 (2855-5829) kcal. The median consumption of carbohydrates, proteins, and fats was 512.3 (358.7-853.5), 184.5 (118.5-246.4), and 137.1 (96.8-189.5) g/d, respectively. Adolescent athletes had higher protein intakes than adult athletes (P = 0.02). Para-athletes with a longer sports career had lower consumption of fiber (P = 0.01) and thiamine (P = 0.02). Participants with a higher body mass index had higher intake of alcohol (P = 0.04) and monounsaturated fats (P = 0.01). Higher consumption of alcohol was also reported by older para-athletes (P = 0.02).

CONCLUSIONS

We identified a higher saturated fat intake in male than in female para-athletes as well as higher protein intake (g/kg) in younger compared with older athletes. In addition, sociodemographic characteristics influenced the dietary intake of some para-athletes, such as length of sports career, age, and income.

Blood biomarkers for estimating energy intake in Japanese male collegiate athletes: a pilot study

BACKGROUND

Athletes should be informed of their required energy intake in preparation for sports competitions. However, the environment in which dietary surveys can be conducted to determine the required energy intake for sports competitions is limited, and such survey will require a substantial amount of time and effort from athletes and dietitians. If certain biomarkers for estimating the energy intake can be identified, they may compensate for the shortcomings of these dietary surveys. We aimed to identify the blood biomarkers to estimate the energy intake/basal metabolic rate ratio of male athletes.

METHODS

Twenty-six male athletes from a university physical education department were included and underwent measurements of height, weight, and body composition, as well as blood sampling. The dietary assessment included a 3-day dietary recall and collection of meal photographs. The basal metabolic rate was estimated using the lean body mass, while the daily energy intake/basal metabolic rate ratio was used as an index to determine the energy intake. From the 36 selected blood biomarkers, we identified the independent biomarkers for inclusion in the multiple regression analysis by assessing for pairwise correlations and multicollinearity. A formula for estimating the energy intake/basal metabolic rate was then developed using the stepwise method. A p-value of < 0.05 was considered significant.

RESULTS

Overall, 18 of the 36 blood biomarkers were selected, and multiple regression analysis revealed that triiodothyronine, white blood cell count, and triglyceride level were significant factors that can be used to estimate the energy intake/basal metabolic rate, accounting for 60.4% of the variance. No systematic errors were observed in the estimated values, calculated using the estimation formula and dietary assessment results.

CONCLUSIONS

A combination of free triiodothyronine level, white blood cell count, and triglyceride level can be used for estimating the energy intake/basal metabolic rate of male athletes, thus compensating for the shortcomings of dietary surveys.

Energy balance and energy availability of female basketball players during the preparation period

OBJECTIVE

To determine the level of energy balance and energy availability (EA) in female basketball players during the preparation period.

METHODS

Fifteen basketball players (age: 19.53 ± 1.3 years; height: 173.6 ± 8.95 cm; weight: 67.55 ± 14.34 kg; training experience: 9.6 ± 2.7 years) and 15 age and body mass index-matched controls (age: 19.53 ± 1.1 years; height: 169.4 ± 5.06 cm; weight: 63.10 ± 6.14 kg) participated in the study. Resting metabolic rate (RMR) and body composition were measured by the indirect calorimetric method and dual-energy x-ray absorptiometry, respectively. A 3-day food diary was used to determine macronutrients and energy intake while a 3-day physical activity log was used to determine energy expenditure. Independent Samples t-test was used for data analysis.

RESULTS

The daily energy intake and expenditure of female basketball players were 2136.5 ± 594.9 kcal·day-1 and 2953.8 ± 614.5 kcal·day-1, respectively, indicating 817 ± 779 kcal·day-1 of negative energy balance. One hundred percent and 66.6% of the athletes failed to meet the carbohydrate and protein intake recommendations, respectively. EA of female basketball players was 33.04 ± 15.69 kcal·fat free mass-1·day-1 and the percentages of athletes who had negative energy balance, low EA, and reduced EA were 80%, 40%, and 46.7%, respectively. However, despite the low and decreased EA, the measured RMR to predicted RMR ratio (RMRratio) was 1.31 ± 0.17 and the body fat percentage (BF%) was 31.00 ± 5.21%.

CONCLUSION

This study shows that female basketball players have a negative energy balance during the preparation period which can be partly explained by insufficient carbohydrate intake. Although most of the athletes experienced low or reduced EA during the preparation period, the physiologically normal RMRratio and relatively high BF% indicate that this is a transient situation. In this regard, strategies to prevent the development of low EA and negative energy balance during the preparation period will contribute to positive training adaptations throughout the competition period.

Mapping the complexities of Relative Energy Deficiency in Sport (REDs): development of a physiological model by a subgroup of the International Olympic Committee (IOC) Consensus on REDs

The 2023 International Olympic Committee (IOC) consensus statement on Relative Energy Deficiency in Sport (REDs) notes that exposure to low energy availability (LEA) exists on a continuum between adaptable and problematic LEA, with a range of potential effects on both health and performance. However, there is variability in the outcomes of LEA exposure between and among individuals as well as the specific manifestations of REDs. We outline a framework for a 'systems biology' examination of the effect of LEA on individual body systems, with the eventual goal of creating an integrated map of body system interactions. We provide a template that systematically identifies characteristics of LEA exposure (eg, magnitude, duration, origin) and a variety of moderating factors (eg, medical history, diet and training characteristics) that could exacerbate or attenuate the type and severity of impairments to health and performance faced by an individual athlete. The REDs Physiological Model may assist the diagnosis of underlying causes of problems associated with LEA, with a personalised and nuanced treatment plan promoting compliance and treatment efficacy. It could also be used in the strategic prevention of REDs by drawing attention to scenarios of LEA in which impairments of health and performance are most likely, based on knowledge of the characteristics of the LEA exposure or moderating factors that may increase the risk of harmful outcomes. We challenge researchers and practitioners to create a unifying and dynamic physiological model for each body system that can be continuously updated and mapped as knowledge is gained.

Short Severe Energy Restriction with Refueling Reduces Body Mass without Altering Training-Associated Performance Improvement

PURPOSE

We investigated short-term (9 d) exposure to low energy availability (LEA) in elite endurance athletes during a block of intensified training on self-reported well-being, body composition, and performance.

METHODS

Twenty-three highly trained race walkers undertook an ~3-wk research-embedded training camp during which they undertook baseline testing and 6 d of high energy/carbohydrate (HCHO) availability (40 kcal·kg FFM -1 ·d -1 ) before being allocated to 9 d continuation of this diet ( n = 10 M, 2 F) or a significant decrease in energy availability to 15 kcal·kg FFM -1 ·d -1 (LEA: n = 10 M, 1 F). A real-world 10,000-m race walking event was undertaken before (baseline) and after (adaptation) these phases, with races being preceded by standardized carbohydrate fueling (8 g·kg body mass [BM] -1 for 24 h and 2 g·kg BM -1 prerace meal).

RESULTS

Dual-energy x-ray absorptiometry-assessed body composition showed BM loss (2.0 kg, P < 0.001), primarily due to a 1.6-kg fat mass reduction ( P < 0.001) in LEA, with smaller losses (BM = 0.9 kg, P = 0.008; fat mass = 0.9 kg, P < 0.001) in HCHO. The 76-item Recovery-Stress Questionnaire for Athletes, undertaken at the end of each dietary phase, showed significant diet-trial effects for overall stress ( P = 0.021), overall recovery ( P = 0.024), sport-specific stress ( P = 0.003), and sport-specific recovery ( P = 0.012). However, improvements in race performance were similar: 4.5% ± 4.1% and 3.5% ± 1.8% for HCHO and LEA, respectively ( P < 0.001). The relationship between changes in performance and prerace BM was not significant ( r = -0.08 [-0.49 to 0.35], P = 0.717).

CONCLUSIONS

A series of strategically timed but brief phases of substantially restricted energy availability might achieve ideal race weight as part of a long-term periodization of physique by high-performance athletes, but the relationship between BM, training quality, and performance in weight-dependent endurance sports is complicated.

Energy expenditure and weight-related behaviors in youth with Down syndrome: a protocol

Background

The consequences of obesity are ominous, yet healthcare professionals are not adequately preventing or treating obesity in youth with Down syndrome (DS). Total daily energy expenditure (TDEE) is the energy expended in 24 h through physical activity and life-sustaining physiologic processes. An individual's TDEE is essential for determining the daily caloric intake needed to maintain or change body weight. Successful prevention and treatment of obesity in youth with DS is severely compromised by the lack of data on TDEE and information on weight-related behaviors for this high-risk population. This manuscript describes the protocol for the federally funded study that is in process to determine daily energy expenditure in a large cohort of children with DS.

Methods

This observational cross-sectional study will include a national sample of 230 youth with DS, stratified by age (5-11 and 12-18 years of age) and sex. Doubly Labeled Water analysis will provide the criterion body fat%, fat-free mass, and TDEE. To increase accessibility and decrease the burden on participants, the entire study, including obtaining consent and data collection, is conducted virtually within the participant's home environment on weekdays and weekends. The study team supervises all data collection via a video conferencing platform, e.g., Zoom. This study will (1) examine and determine average TDEE based on age and sex, (2) develop a prediction equation based on measured TDEE to predict energy requirements with a best-fit model based on fat-free mass, sex, age, and height and/or weight, and (3) use 24-hour dietary recalls, a nutrition and physical activity screener, wearable devices, and sleep questionnaire to describe the patterns and quality of dietary intake, sleep, and physical activity status in youth with DS.

Discussion

The lack of accurate information on energy expenditure and weight-related behaviors in youth with DS significantly impedes the successful prevention and treatment of obesity for this vulnerable population. The findings of this study will provide a further understanding of weight-related behaviors as obesity risk factors, currently not well understood for this population. This study will advance the science of weight management in individuals with disabilities and shift clinical practice paradigms.

Factors affecting nutritional knowledge, attitude, practices and dietary intake among national players in Kathmandu, Nepal: a cross-sectional study

INTRODUCTION

Good nutrition knowledge and nutrient intake have been regarded as significant determinants in enhancing athletes' performance and overall health status. This study aimed to assess knowledge, attitude, and practices of nutrition and dietary intake among athletes.

METHODS

A cross-sectional study was conducted from January to April 2022 among national athletes from two sports clubs in Kathmandu Metropolitan City, Nepal. A semi-structured questionnaire was used to collect the data. Anthropometric measurements and dietary intake were recorded. Bivariate and multivariate binary logistic regression was used to estimate the crude odds ratios (cOR), and adjusted odds ratios (aOR) with 95% confidence intervals (CIs).

RESULTS

A total of 270 players were included in this study (mean age, 25 years; 49.6% male, 50.4% female). Almost half of the athletes had good nutrition knowledge [54.1% (146/270)], attitude [56.7% (153/270)], and practices [50% (135/270)] scores. The mean energy, carbohydrate, protein, and fat intake were 35.0 kcal/kg/day, 5.6, 0.9, and 0.9 g/kg/day, respectively. Likewise, mean calcium and iron intake were 370, and 12.5 mg, respectively. In the multivariate model, families with monthly household income less than 50,000 Nepalese rupees ($400) (adjusted Odds Ratio/aOR = 2.58; 95% CI: 1.12 to 5.96), and those who did not receive diet plan (aOR = 3.14; 95% CI: 1.25 to 7.84) were more likely to have poor nutrition knowledge. Players who did not check food labelling (aOR = 1.44; 95% CI: 0.78 to 2.63) were more likely to have negative attitude towards nutrition. Players who did not ever attend nutrition class (aOR = 3.54; 95% CI: 1.46 to 8.54) and those who did not consume different food during off and on the season of sports (aOR = 2.36; 95% CI: 1.39 to 4.01) were more likely to have poor nutrition practice.

CONCLUSIONS

Half of the athletes' nutritional knowledge, attitudes, and practices score were satisfactory. Nutrient intake among athletes was suboptimal. Nutrition intervention programs are critical to improve nutritional knowledge, attitude and practice related to dietary intake among national athletes in Nepal.

Energy Availability and Nutritional Intake during Different Training Phases of Wheelchair Athletes

Optimizing nutritional intake and timing helps athletes to improve performance and long-term health. Different training phases can require varying nutritional needs. In this study, we conducted a descriptive assessment of dietary intake, energy availability (EA), and blood biochemical parameters in elite wheelchair athletes during distinct training phases. Data analyzed in this study were collected as part of a randomized controlled crossover trial exploring the feasibility of probiotics and prebiotic supplementation. Data were obtained from consecutive three-day diaries and blood samples, both collected at four different time points across four consecutive months. We included 14 athletes (mean (standard deviation) age 34 (9) years, eight females, and six males) active in different wheelchair sports. The mean daily nutritional intake (g/kg body mass) for females and males was 2.7 (0.9) and 4.0 (0.7) for carbohydrates, 1.1 (0.3) and 1.5 (0.3) for protein, and 0.8 (0.3) and 1.4 (0.2) for fat. EA did not change across the four time points in either female (p = 0.30) or male (p = 0.05) athletes. The mean EA was lower in female athletes compared to male athletes (p = 0.03). Low EA (≤30 kcal/ kg fat-free mass/day) was observed in female (58 (29) % of days) and male (34 (23) % of days) athletes. Iron deficiency with anemia was observed in two female athletes. Mean vitamin D levels were insufficient (<75 nmol/L). Macronutrient intake, EA, and blood biochemical parameters were suboptimal in this cohort of elite wheelchair athletes, especially in female athletes.

Unraveling the mystery of isocaloric endurance training - Influence of exercise modality, biological sex, and physical fitness

BACKGROUND

A sedentary lifestyle with low energy expenditure (EE) is associated with chronic diseases and mortality. Barriers such as "lack of time" or "lack of motivation" are common reasons why physical exercise is neglected in the general population. To optimize EE in the time available, time-efficient but also enjoyable types of exercise are required. We therefore used an isocaloric approach to systematically investigate the effects of six different endurance exercise modalities on metabolic, mechanical, cardiorespiratory, and subjective variables in relation to biological sex and physical fitness.

METHODS

Out of 104, 92 healthy participants (21 recreationally trained and 18 trained females, 25 recreationally trained and 28 trained males) were subjected to physiological exercise testing to determine the exercise intensities for six exercise modalities, i.e., three different high-intensity interval training (HIIT) protocols (5 × 4 min, 15 × 1 min, 30 × 30 sec intervals), threshold (THR), speed endurance production (SEP), and low-intensity training (LIT). One of three HIIT sessions served as the reference for the subsequent isocaloric exercise modalities which were completed in randomized order. Metabolic and mechanical variables, i.e., EE during exercise, time to isocaloric EE (T_iso), relative and absolute fat contribution, post-exercise oxygen consumption (EPOC), mechanical energy, as well as cardiorespiratory and subjective variables, i.e., heart rate, oxygen uptake response, rating of perceived exertion, and enjoyment were assessed. Data were analyzed using a 6 × 2 × 2 repeated-measures ANOVA.

RESULTS

All three versions of HIIT and THR achieved the same EE during exercise for the same training duration. We found that LIT had a 1.6-fold (p < 0.001) and SEP a 1.3-fold (p < 0.001) longer T_iso compared to HIIT with no effects of biological sex (p = 0.42, _pη² = 0.01) or physical fitness (p = 0.09, _pη² = 0.04). There was a main effect of exercise modality on EPOC (p < 0.001, _pη² = 0.76) with highest values for HIIT 30 × 30 (p = 0.032) and lowest for LIT (p < 0.001). The highest relative and absolute amounts of fatty acids were measured during LIT (p < 0.001), and the lowest values were obtained during HIIT modalities. HIIT 30 × 30 was the most enjoyable version of HIIT (p = 0.007), while THR was the least enjoyable exercise modality (p = 0.008).

CONCLUSION

HIIT modalities are time-saving and enjoyable, regardless of sex and physical fitness. The results illustrate the relationship between exercise modality and metabolic, physiological, and subjective responses, and are thus of great interest to healthy individuals seeking time-saving and enjoyable exercise options.

The Low Energy Availability in Females Questionnaire (LEAF-Q) as a Useful Tool to Identify Female Triathletes at Risk for Menstrual Disorders Related to Low Energy Availability

BACKGROUND

Nutrition in sport is a priority; it is the basis for maintaining optimal health and a prerequisite for the high performance necessary for competitions. The aim of this study was to assess low energy availability and its possible consequences among female triathletes by using the Low Energy Availability in Females Questionnaire (LEAF-Q).

METHODS

The study involved 30 female triathetes. The LEAF-Q was used in the study. An analysis of the body composition was carried out with the seca device mBCA 515 medical Body Composition Analyzer.

RESULTS

Of the 30 female triathletes studied, 23.3% had a monthly cycle disorder, defined as an amenorrhea state for more than 90 days. No differences were found in injury rates or training days lost to injury due to menstrual disturbances. Menstruation changes were significantly greater due to increases in exercise intensity, frequency, and duration in the group experiencing menstrual disturbances (85.7 [95% CIs: 42.1-99.6] vs. 8.7 [95% CIs: 1.1-28.0]). The menstrual disorder group had a greater incidence of their periods stopping for more than 3 months than the group without menstrual disturbances.

CONCLUSIONS

The female triathletes did not show abnormalities in body weight or composition, and these were not related to the incidence of menstrual disturbances. However, 20% of the triathletes either had, at the time of the study, or had had in the past monthly cycle disorders that could indicate an immediate risk of low energy availability. The LEAF-Q identified 10% of the triathletes as at risk (score > 8) of low energy availability and the physiological and performance consequences related to relative energy deficiency in sports (RED-S).

The Effect of a Hydroxytyrosol-Rich, Olive-Derived Phytocomplex on Aerobic Exercise and Acute Recovery

There is current scientific interest in naturally sourced phenolic compounds and their potential benefits to health, as well as the effective role polyphenols may provide in an exercise setting. This study investigated the chronic effects of supplementation with a biodynamic and organic olive fruit water phytocomplex (OliPhenolia® [OliP]), rich in hydroxytyrosol (HT), on submaximal and exhaustive exercise performance and respiratory markers of recovery. Twenty-nine recreationally active participants (42 ± 2 yrs; 71.1 ± 2.1 kg; 1.76 ± 0.02 m) consumed 2 × 28 mL∙d−1 of OliP or a taste- and appearance-matched placebo (PL) over 16 consecutive days. Participants completed a demanding, aerobic exercise protocol at ~75% maximal oxygen uptake (V˙O2max) for 65 min 24 h before sub- and maximal performance exercise tests prior to and following the 16-day consumption period. OliP reduced the time constant (τ) (p = 0.005) at the onset of exercise, running economy (p = 0.015) at lactate threshold 1 (LT1), as well as the rating of perceived exertion (p = 0.003) at lactate turnpoint (LT2). Additionally, OliP led to modest improvements in acute recovery based upon a shorter time to achieve 50% of the end of exercise V˙O2 value (p = 0.02). Whilst OliP increased time to exhaustion (+4.1 ± 1.8%), this was not significantly different to PL (p > 0.05). Phenolic compounds present in OliP, including HT and related metabolites, may provide benefits for aerobic exercise and acute recovery in recreationally active individuals. Further research is needed to determine whether dose-response or adjunct use of OliP alongside longer-term training programs can further modulate exercise-associated adaptations in recreationally active individuals, or indeed support athletic performance.

Sex differences and indications of metabolic compensation in within-day energy balance in elite Division 1 swimmers

To determine whether mismatched energy intake and expenditure across the day and associated sex differences may be related with metabolic compensation and/or negative health outcomes, we assessed total-day and hourly energy balance (TDEB and EB), total-day and hourly energy intake (TDEI and EI), total-day and hourly energy expenditure (TDEE and EE) and within-day energy balance (WDEB) in elite male and female swimmers (n = 25; 18-22 years). Total triiodothyronine (TT₃), resting metabolic rate (RMR), and the ratio of actual-to-predicted RMR were determined. Males exhibited higher TDEB (+758 ± 702 kcal vs +52 ± 505 kcal, t-test; p = 0.007) than females. Males exhibited a more positive hourly EB, driven by greater hourly EI at 11:00, 13:00, 16:00, and 19:00 h (ANOVA, p < 0.05), while EE did not differ. TT₃ was negatively correlated with consecutive hours of negative EB (R = -0.604, p = 0.049) and positively correlated to hours in EB (R = 0.740, p = 0.009) in those exhibiting metabolic suppression (n = 12). In individuals in TDEB (n = 21), "backloaders" (consumption of ≥50% daily kcals at or after 1700 h) had lower TT₃ (79.3 ng/dL vs 92.9 ng/dL, p = 0.009) than "nonbackloaders" (n = 12). WDEB analyses indicate a greater risk of energy deficiency in females and may capture indices of metabolic compensation not evident with EB analyses alone.

The Impact of a 'Remotely-Delivered' Sports Nutrition Education Program on Dietary Intake and Nutrition Knowledge of Junior Elite Triathletes

Triathlon is a physically demanding sport, requiring athletes to make informed decisions regarding their daily food and fluid intake to align with daily training. With an increase in uptake for online learning, remotely delivered education programs offer an opportunity to improve nutritional knowledge and subsequent dietary intake in athletes. This single-arm observational study aimed to evaluate the effectiveness of a remotely delivered nutrition education program on sports nutrition knowledge and the dietary intake of junior elite triathletes (n = 21; female n = 9; male n = 12; 18.9 ± 1.6 y). A total of 18 participants completed dietary intake assessments (4-day food diary via Easy Diet DiaryTM) and 14 participants completed an 83-question sports nutrition knowledge assessment (Sports Nutrition Knowledge Questionnaire (SNKQ)) before and after the 8-week program. Sports nutrition knowledge scores improved by 15% (p < 0.001, ES = 0.9) following the program. Male participants reported higher energy intakes before (3348 kJ, 95% CI: 117−6579; p = 0.043) and after (3644 kJ, 95% CI: 451−6836; p = 0.028) the program compared to females. Carbohydrate intake at breakfast (p = 0.022), daily intakes of fruit (p = 0.033), dairy (p = 0.01) and calcium (p = 0.029) increased following nutrition education. Irrespective of gender, participants had higher intakes of energy (p < 0.001), carbohydrate (p = 0.001), protein (p = 0.007), and fat (p = 0.007) on heavy training days compared to lighter training days before and after the program with total nutrition knowledge scores negatively correlated with discretionary food intake (r = −0.695, p = 0.001). A remotely delivered nutrition education program by an accredited sports nutrition professional improved sports nutrition knowledge and subsequent dietary intake of junior elite triathletes, suggesting remote delivery of nutrition education may prove effective when social distancing requirements prevent face-to-face opportunities.

Energy Availability Over One Athletic Season: An Observational Study Among Athletes From Different Sports

During the athletic season, changes in body composition occur due to fluctuations in energy expenditure and energy intake. Literature regarding changes of energy availability (EA) is still scarce. The aim was to estimate EA of athletes from nonweight and weight-sensitive sports during the athletic season (i.e., preparatory and competitive phase). Eighty-eight athletes (19.1 ± 4.2 years, 21.8 ± 2.0 kg/m2, 27% females, self-reported eumenorrheic) from five sports (basketball [n = 29]; handball [n = 7]; volleyball [n = 9]; swimming [n = 18]; and triathlon [n = 25]) were included in this observational study. Energy intake and exercise energy expenditure were measured through doubly labeled water (over 7 days and considering neutral energy balance) and metabolic equivalents of tasks, respectively. Fat-free mass (FFM) was assessed through a four-compartment model. EA was calculated as EA = (energy intake - exercise energy expenditure)/FFM. Linear mixed models, adjusted for sex, were performed to assess EA for the impact of time by sport interaction. Among all sports, EA increased over the season: basketball, estimated mean (SE): 7.2 (1.5) kcal/kg FFM, p < .001; handball, 14.8 (2.9) kcal/kg FFM, p < .001; volleyball, 7.9 (2.8) kcal/kg FFM, p = .006; swimming, 8.7 (2.0) kcal/kg FFM, p < .001; and triathlon, 9.6 (2.0) kcal/kg FFM, p < .001. Eleven athletes (12.5%) had clinical low EA at the preparatory phase and none during the competitive phase. During both assessments, triathletes' EA was below optimal, being lower than basketballers (p < .001), volleyballers (p < .05), and swimmers (p < .001). Although EA increased in all sports, triathlon's EA was below optimal during both assessments. Risk of low EA might be seasonal and resolved throughout the season, with higher risk during the preparatory phase. However, in weight-sensitive sports, namely triathlon, low EA is still present.

A theory-based model of cumulative activity

Energy expenditure can be used to examine the health of individuals and the impact of environmental factors on physical activity. One of the more common ways to quantify energy expenditure is to process accelerometer data into some unit of measurement for this expenditure, such as Actigraph activity counts, and bin those measures into physical activity levels. However, accepted thresholds can vary between demographics, and some units of energy measurements do not currently have agreed upon thresholds. We present an approach which computes unique thresholds for each individual, using piecewise exponential functions to model the characteristics of their overall physical activity patterns corresponding to well established sedentary, light, moderate and vigorous activity levels from the literature. Models are fit using existing piecewise fitting techniques and software. Most participants’ activity intensity profile is exceptionally well modeled as piecewise exponential decay. Using this model, we find emergent groupings of participant behavior and categorize individuals into non-vigorous, consistent, moderately active, or extremely active activity intensity profiles. In the supplemental materials, we demonstrate that the parameters of the model correlate with demographics of age, household size, and level of education, inform behavior change under COVID lockdown, and are reasonably robust to signal frequency.

Prevalence of Female and Male Vegan and Non-Vegan Endurance Runners and the Potential Associations of Diet Type and BMI with Performance-Results from the NURMI Study (Step 1)

This study aims to investigate vegetarian and mixed diet type prevalences among distance runners at running events around the world and associations with running-related patterns and performance. Following a cross-sectional approach, linear regression analyses were carried out to identify potential associations among body mass index (BMI), diet type, and average best performance times of half-marathon and marathon events for males and females. From a sample of 3835 runners who completed an online questionnaire, 2864 all-distance runners (age: 37 years; 57% females) were included in inferential analyses and categorized into dietary subgroups according to self-reports: 994 vegans (34.7%), 598 vegetarians (20.9%), and 1272 omnivores (44.4%). Significant associations were identified between kind of diet and best average time to finish (i) half-marathons in females where vegans (p = 0.001) took longer than omnivores, (ii) half-marathons in males where vegans (p < 0.001) and vegetarians (p = 0.002) took longer than omnivores, and (iii) marathons in males where vegans (p < 0.001) and vegetarians (p = 0.043) averaged slower than omnivores. Increased units of BMI (+1.0) in males influenced best runtimes: 2.75 (3.22−2.27) min slower for HM and 5.5 (5.69−4.31) min slower for M. The present study did not take detailed confounders into account such as runner motives or training behaviors; however, the results may provide valuable insight for running event organizers, nutrition experts, coaches, and trainers advising runners who adhere to a general diet type regarding the basic question of who participates in running events around the world.

Female Athlete Triad and Male Athlete Triad Syndrome Induced by Low Energy Availability: An Animal Model

Energy availability (EA) is defined the difference in energy intake and exercise energy expenditure. Reduction of EA (i.e. Low energy availability, LEA) often causes abnormalities of reproduction system and drastic bone loss in some female athletes, the phenomenon is called as female athlete triad. More than ever before, it is considered a serious problem, the reason of these are (1) the syndrome occurred in female athletes but also male athletes, (2) LEA is leads to dysfunction of various organs other than reproductive system (Relative energy deficiency in sport, RED-S). On the other hand, we have focused on this syndrome and have proposed novel insights into the physiological effects of LEA on bone and solutions through nutritional treatment by recreating it in animal models. In this review, we will summarize the epidemiological and physiological perspectives of these diseases from historical background to recent findings, and introduce the usefulness of using animal models to explore mechanisms and treatments.

A Comparative and Sex-Specific Study of Bio-Electrical Impedance Analysis and Dual Energy X-ray Absorptiometry for Estimating Whole-Body and Segmental Body Composition in Healthy Young Adults

Bio-electrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA) are methods to estimate human body composition. This study aimed to compare sex-specific outcomes for estimating segmental and whole-body composition in 83 healthy participants (21.9 ± 1.5 years, 56% men) using Inbody S10 BIA and Norland Elite DXA devices. One-way repeated measures ANOVAs showed significantly lower whole-body fat% and whole-body fat mass values alongside higher whole-body lean mass values resulting from BIA when compared to DXA (both sexes: p < 0.001). In men, whole-body bone mineral content was significantly higher using BIA against DXA (p < 0.001). Regardless of sex, no significant BIA versus DXA difference was found in arm fat mass (men: p = 0.180, women: p = 0.233), whereas significantly lower leg fat mass values were found with BIA versus DXA (both sexes: p < 0.001). Additionally, significantly higher arm lean mass (both sexes: p < 0.001) and leg lean mass (only women: p < 0.001) were found in BIA versus DXA. Moderate to very strong positive associations (p < 0.05) between BIA and DXA outcome measures were found, except for arm fat mass (men: p = 0.904, women: p = 0.130) and leg fat mass (only men: p = 0.845). This study highlights (sex-dependent) differences in corresponding test outcomes between BIA and DXA both at the segmental and whole-body level.

The impact of 16-h heat exposure on appetite and food reward in adults

Heat exposure is thought to reduce energy intake (EI) but studies are sparse and results not always concordant. The aim of this study was to examine whether a 16-h exposure to 32 °C leads to reduced EI compared to a control session (22 °C) and whether modifications in appetite sensations or food reward are implied. Sixteen healthy, lean, and active participants (9 women and 7 men, 25 ± 5 yo, body mass index: 22.0 ± 2.4 kg.m^-2) were passively exposed to two different thermal temperatures from 4:00 pm to 8:00 am under controlled conditions. Hunger and thirst scores were regularly assessed using visual analogue scales. A fixed dinner meal (3670 ± 255 kJ) was consumed at 7:30 pm and an ad libitum breakfast buffet (20 foods/drinks varying in temperature, fat, and carbohydrate content) at 7:30 am. Components of reward (explicit liking [EL] and implicit wanting [EI]) for fat and sweet properties of food were assessed before each meal using the Leeds Food Preference Questionnaire (LFPQ). Ad libitum EI at breakfast did not differ between sessions (2319 ± 1108 vs 2329 ± 1141 kJ, in 22 and 32 °C sessions, respectively; p = 0.955). While thirst scores were higher in the 32 than the 22 °C session (p < 0.001), hunger scores did not differ (p = 0.580). EL and IW for high fat foods relative to low fat foods were decreased in 32 compared to 22 °C before dinner and breakfast (p < 0.001 for all). Although EI and hunger were not affected by a 16-h exposure to heat, modifications in food reward suggested a reduction in the preference of high-fat foods. Future research should investigate whether reduced EI in response to heat exposure is due to spontaneous selection of low-fat foods rather than altered appetite sensations.

Female Endurance Runners Have a Healthier Diet than Males-Results from the NURMI Study (Step 2)

Sex has been recognized to be an important indicator of physiological, psychological, and nutritional characteristics among endurance athletes. However, there are limited data addressing sex-based differences in dietary behaviors of distance runners. The aim of the present study is to explore the sex-specific differences in dietary intake of female and male distance runners competing at >10-km distances. From the initial number of 317 participants, 211 endurance runners (121 females and 90 males) were selected as the final sample after a multi-level data clearance. Participants were classified to race distance (10-km, half-marathon, marathon/ultra-marathon) and type of diet (omnivorous, vegetarian, vegan) subgroups. An online survey was conducted to collect data on sociodemographic information and dietary intake (using a comprehensive food frequency questionnaire with 53 food groups categorized in 14 basic and three umbrella food clusters). Compared to male runners, female runners had a significantly greater intake in four food clusters, including “beans and seeds”, “fruit and vegetables”, “dairy alternatives”, and “water”. Males reported higher intakes of seven food clusters, including “meat”, “fish”, “eggs”, “oils”, “grains”, “alcohol”, and “processed foods”. Generally, it can be suggested that female runners have a tendency to consume healthier foods than males. The predominance of females with healthy dietary behavior can be potentially linked to the well-known differences between females and males in health attitudes and lifestyle patterns.