The effect of the holiday season on body weight and composition in college students

Holiday Weight Change in a US College Student Sample: A Prospective Observational Cohort Study

Objective

The November through January holiday period is often thought to produce weight gain, coined "holiday weight gain." While this trend has been documented among early to midlife adults, it is less certain whether college students experience similar levels of weight gain during this period, as they undergo lifestyle changes (e.g., returning to their families of origin) that may differ from adults at later stages of development. Thus, the primary aim of the current study was to determine body weight and body composition changes during the holiday season in college students. The secondary aim was to examine the association of psychosocial variables with primary outcomes.

Methods

Participants included 47 undergraduate students. Body weight, body composition, and psychosocial variables were measured prior to Thanksgiving break and after returning from December to January break. Differences in body weight and body composition variables were determined using paired-sample t-tests. Associations of psychosocial variables with changes in primary outcomes were determined by Spearman's correlation coefficients and linear regressions.

Results

On average, college students experienced a 1.08% increase in body weight between study visit 1 in November and study visit 2 in January (0.74 ± 1.81 kg; p = 0.02). Lean mass increased (1.49 ± 3.21 kg; p = 0.01), while body fat % did not change (p = 0.12). Psychosocial variables were not significantly associated with or predictive of changes in body weight or body fat % (p's > 0.05).

Conclusions

College students gained a small, yet significant, amount of weight over the holiday period. Weight gain occurred alongside increases in lean mass but not body fat. Results provide important context to previous findings observing weight gain in college students and adults over the holiday season. Specifically, findings indicate a healthy increase in lean mass-a potential promotive factor in optimal health and wellbeing.

Winter Holidays and Their Impact on Eating Behavior-A Systematic Review

(1) Background: There has been a growing interest in understanding the causes of obesity and developing effective prevention strategies. Lifestyle change programs are often considered the gold standard for weight reduction, and they can help individuals with obesity achieve an annual weight loss of around 8-10%. The aim of this review was to evaluate the effect of food during the winter holidays. This knowledge will serve as a valuable foundation for the development of targeted interventions and prevention programs. (2) Methods: We conducted a systematic search of the literature via one database (PubMed). The search was limited to studies published in English in the last 10 years, with adult participants, but without specifying limits regarding the study design. We excluded articles that addressed intermittent fasting diets or weight loss intervention methods during the holidays through various diets. (3) In separate sections, we analyzed the psychological causes of gaining weight during the winter holidays, behavioral patterns, prevention strategies and the nutritional composition of the different types of food served during the festive period. Results: Using the combination of the terms "holiday and obesity", "holiday and weight gain", "festive season and obesity", and "festive season and weight gain" we obtained 216 results involving the addressed topic. Thus, only ten articles remained after screening, with a total of 4627 participants. Most participants experienced weight fluctuations during the study period, particularly during holidays. One concerning observation was that most of the weight gained during these periods was maintained even after the end of the studies, especially in those with obesity. A supervised exercise program and a controlled diet at work over the Christmas period are effective strategies for avoiding weight gain and its deleterious effects in people with metabolic syndrome or weight problems. (4) In addition, attention must be focused on the psycho-social factors during the holidays because for some people it is a stressful period and can cause a much higher caloric consumption. The simplest method to approach during the holidays is to implement small tips and tricks during this period that will prevent individuals from gaining extra pounds. Conclusions: It is essential to acknowledge that obesity is a multifaceted condition that requires a comprehensive and multidisciplinary approach to address its underlying factors and provide ongoing assistance to individuals in their weight-management endeavors. Even the most effective short-term interventions are likely to produce continued positive outcomes with persistent intervention and support.

Body Composition Changes in College Athletes During Holiday Breaks

Background

Changes in eating and physical activity during the winter holiday season are commonly associated with weight gain in the general population. Concerns around weight and fat gain are also relevant to collegiate athletes who are generally unable to access on-campus dining and exercise facilities during this time. These concerns were exaggerated in 2020 due to changes in the academic and sports calendar as a result of the COVID-19 pandemic that lead to a holiday break that was 3 weeks longer than normal for many college athletes. The purpose of this study was to investigate changes in Body Mass Index (BMI), Fat Mass Index (FMI) and Muscle Mass Index (MMI) among college athletes during an extended and usual holiday break.

Methods

Fat mass, muscle mass, and weight were measured using bioelectrical impedance analysis as part of routine care in college athletes within two weeks of leaving campus and return to campus during the extended winter break in 2020 (n = 124 athletes) and the usual winter break in 2021 (n = 64 athletes). Change values were calculated for each dependent variable. Differences between extended and normal winter breaks, male and female athletes, and a sex*break interaction were assessed using ANCOVA (BMI and FMI) and Kruskal-Wallis Test (MMI). All analyses were completed using SAS 9.4.

Results

A significant sex*break interaction was observed for BMI and FMI. Male athletes gained BMI and FMI during the extended winter break compared to other sex*break conditions. No differences were found for change in MMI across conditions.

Conclusions

These results demonstrate potential differences in weight and fat mass changes between male and female athletes during an extended holiday break. Future research should investigate whether body composition changes occur during other breaks athletes experience (e.g., summer break) and determine how weight-impacting behaviors such as diet and physical activity differ when they are on campus versus at home. This research can help athletics staff implement strategies to best help athletes maintain optimal body composition and performance during breaks.

A systematic review of temporal body weight and dietary intake patterns in adults: implications on future public health nutrition interventions to promote healthy weight

PURPOSE

The global prevalence of overweight remains high; effective strategies that consider patterns of body weight changes to identify periods when adults are susceptible to weight gain are warranted. This systematic review aimed to investigate body weight patterns, and how they were associated with dietary intake and/or dietary behaviours (Prospero CRD42020161977).

METHODS

Systematic literature search was conducted in the Medline, Embase, and CINAHL databases until November 2020. Observational studies in adults (18 years and over) that reported at least two measurements of weight and dietary intake in a year were included. Risk of bias was conducted using the Evidence Analysis Library by the Academy of Nutrition and Dietetics tool. This review included 16 unique studies after title, abstract, and full-text screening, and findings were narratively synthesised.

RESULTS

Of the six studies conducted in the farming populations, five were conducted in countries with two seasons (dry vs. rainy seasons) and all studies observed higher body weight during the dry season (up to 3.1 kg difference between seasons). The remaining study was conducted in a sub-tropical country and did not observe temporal weight patterns. Higher dietary intake was also reported during the dry season in the tropical countries. In non-farming populations (n = 10), temporal patterns were also seen, where higher body weight and adiposity was observed during colder seasons (autumn and winter). However, the opposite was found in a study conducted in Iran, where higher weight was seen in summer. Concurrent with higher body weight, higher energy, fat, carbohydrate and soda consumption, and lower fiber and vegetable intake were observed.

CONCLUSION

Temporal weight and dietary patterns exist, and they were country- and context-specific; these patterns were also related to factors such as activity levels, seasons and occupation. Future interventions should consider temporal patterns in the design and delivery of timely and tailored dietary interventions to promote optimal body weight.

PROSPERO REGISTRATION

PROSPERO Registration: CRD42020161977.

Changes in Season Affect Body Weight, Physical Activity, Food Intake, and Sleep in Female College Students: A Preliminary Study

The current study examined how body weight and lifestyle fluctuate between spring, autumn, and winter in Japanese female college students and whether weight gain is associated with changes in physical activity, food intake, and sleep. We measured body weight and lifestyle factors in 31 participants from May 2017 to January 2018. Weight was measured daily in participants’ homes. Physical activity and sleep were measured for three weeks in three seasons using two accelerometers. Food intake was assessed using a validated food frequency questionnaire. Body weight significantly decreased in autumn compared with spring (p < 0.001). Body weight in winter tended to increase compared with autumn (p = 0.052). Step counts and energy intake were significantly different between seasons (p < 0.05). Total time in bed was not significantly different between seasons. In comparisons of changes in lifestyle patterns from autumn to winter between the weight gain (≥0.5 kg) and weight maintenance groups, seasonal changes in lifestyle factors were not significantly different between groups (p > 0.05). The results indicated that body weight and lifestyle were affected by seasonal variability in female college students, but no significant relationships existed between seasonal weight gain and changes in lifestyle patterns.

Seasonal fluctuations in weight and self-weighing behavior among adults in a behavioral weight loss intervention

PURPOSE

The current study aimed to observe potential seasonal fluctuations in weight and self-weighing behavior among a diverse sample of adults engaged in a behavioral weight loss intervention.

METHODS

Active duty personnel (N = 248) were randomized to either a counselor-initiated or self-paced 12-month behavioral weight loss intervention promoting daily self-weighing. Body weight and self-weighing frequency were collected from electronic scales (e-scales) provided at baseline.

RESULTS

Overall, participants lost weight from winter to spring (p = 0.02) and gained weight from fall to winter (p < 0.001). No demographic differences in weight changes were observed. Participants self-weighed less frequently during summer compared to spring (p < 0.0001), less in fall compared to summer (p < 0.0001), and less in winter compared to fall (p < 0.0001). In multivariate models, weight change and self-weighing frequency during the previous season, as well as days since randomization and intervention intensity were associated with seasonal weight changes.

CONCLUSIONS

This study is the first to observe seasonal fluctuations of weight and self-weighing behavior among adults actively engaged in a weight loss intervention, consistent with research in the general population. Findings highlight the importance of acknowledging seasonal influence within weight loss programs and trials.

LEVEL OF EVIDENCE

Level I, randomized controlled trial.

Effect of a Single Nutritional Intervention Previous to a Critical Period of Fat Gain in University Students with Overweight and Obesity: A Randomized Controlled Trial

BACKGROUND

the present study aimed to investigate the effects of a single nutritional preventive session previous to a critical period linked to fat gain in university students with overweightness and obesity, emulating a nutritional session of a public health system.

METHODS

In this single-blind randomized controlled trial, 23 students met all the criteria to be included (20.91 ± 2.52-year-old; 52.2% women) who were divided into two groups: intervention group (IG) and control group (CG). Fat mass (FM) by dual-energy X-ray absorptiometry (DXA), physical activity by accelerometry, feeding evaluation through three questionnaires, and a set of healthy lifestyle recommendations were evaluated before and after the national holidays (NH).

RESULTS

Our findings showed that FM increased significantly in the CG, but not in the IG (CG = 428.1 g; IG = 321.9 g; Δ = 106.2 g; p = 0.654 [95% CI = -379.57, 591.92]). However, no differences were found during the NH between them (Hedges' g effect size = 0.19; p = 0.654). In addition, no statistical differences were observed between groups in feeding evaluations, the set of recommendations performed, and physical activity.

CONCLUSION

a single preventive session before a critical period, using a similar counselling approach as used in the public health system, might not be enough to promote changes in eating and physical activity patterns and preventing fat gain in overweight/obese university students. Long-term interventions are a must.

Effects of Exercise Training during Christmas on Body Weight and Cardiometabolic Health in Overweight Individuals

Individuals with abdominal obesity and metabolic syndrome (MetS) have augmented risk of all-cause mortality. Lifestyle interventions are effective to treat MetS, however, there are periods during the year in which exercise programs are discontinued and improper dietary habits reappear (e.g., Christmas holidays). We aimed to analyze if exercise-training during Christmas holidays would avoid body-weight gains and cardiometabolic deterioration in MetS individuals, using a randomized control trial. Thirty-eight men with MetS undergoing exercise training were randomly allocated to either continue (TRAIN group, n = 16) or discontinue (HOLID group, n = 22) training, during the three weeks of Christmas. Anthropometrics (body weight, fat, and waist circumference), fasting blood metabolites (glucose, insulin, triglycerides, and cholesterol concentrations) and exercise maximal fat oxidation (FO_MAX) and oxygen uptake (VO_2PEAK) were determined before and after Christmas. Both groups were similar at baseline in all parameters (p > 0.05). HOLID group increased body weight (91.3 ± 13.0 to 92.0 ± 13.4 kg, p = 0.004), mean arterial pressure (94.0 ± 10.6 to 97.1 ± 8.9 mmHg, p = 0.026), blood insulin (10.2 ± 3.8 to 12.5 ± 5.4 µIU·mL⁻¹, p = 0.003) and HOMA (3.2 ± 1.3 to 4.1 ± 2.3, p = 0.003). In contrast, TRAIN prevented those disarrangements and reduced total (170.6 ± 30.6 to 161.3 ± 31.3 mg·dL⁻¹, p = 0.026) and low-density lipoprotein cholesterol (i.e., LDL-_C, 104.8 ± 26.1 to 95.6 ± 21.7 mg·dL⁻¹, p = 0.013). TRAIN also prevented the reductions in exercise FO_MAX and VO_2PEAK that was observed in the HOLID group (p = 0.002). In conclusion, exercise training during Christmas, prevents body weight gains and the associated cardiovascular (increase in blood pressure and LDL_-C) and metabolic (reduced insulin sensitivity) health risks are an optimal non-pharmacological therapy for that period of the year.

Change in eating pattern as a contributor to energy intake and weight gain during the winter holiday period in obese adults

Background/Objectives:

The winter holiday season in the US, which spans mid-November to mid-January, contributes to over half of annual body weight gain. Although self-reported data has linked this weight change to both increased energy intake and reduced physical activity, objective techniques have never been used and thus the actual cause of holiday weight gain is controversial. Here, we aimed to determine changes in components of energy balance leading to the holiday weight gain.

Methods:

Body weight change was compared between the pre-holiday (mid-September to mid-November) and the holiday period (mid-November to early January). Total energy expenditure (TEE) was measured using doubly labeled water during holiday time (early to mid-December). Subjective (ratings) and physiological (appetite-regulating hormones) measures of appetite, eating-away-from-home frequency, and incentive salience of food pictures were also evaluated.

Results:

In 23 obese adults (87% female), body weight change during the holidays (0.41 ± 0.42 kg) was significantly higher (P=0.02) than the body weight change during the pre-holiday period (−0.86 kg ± 0.42 kg). The TEE was unchanged during the two periods, suggesting no role of energy expenditure on weight gain. However, participants reported lower satisfaction after a meal pre-load which was significantly correlated with increased body weight during the holiday period. An increase in number of episodes of eating at sit-down restaurants was also reported during that period. Overall, these changing behaviors were supported by a non-significant increase in energy intake (+80 kcal/day, P=0.07) observed during the study holiday period.

Conclusion:

We conclude that a decrease in energy expenditure does not result in the weight increase, but that an increase in food intake is the more likely cause. Our data imply that compromised internal satiety mechanisms in presence of external food cues and diet related behavioral variables during the holidays may influence this weight gain.

The Relationship Between Feasting Periods and Weight Gain: a Systematic Scoping Review

PURPOSE OF REVIEW

Whilst evidence indicates that weight gain occurs over holidays, the contribution of specific festive periods and celebrations to eating behaviour and weight gain is unclear. We aimed to synthesise literature on how festive periods and celebrations contribute to population weight gain and weight-related outcomes.

RECENT FINDINGS

Thirty-nine studies examining (i) body weight changes, (ii) determinants of eating behaviour or (iii) weight-gain prevention interventions during festive periods were systematically reviewed. Of the 23 observational studies examining changes in body weight during festive periods, 70% found significant increases (mean 0.7 kg). Only four studies investigated exposure to food cues and overeating during these periods, with heterogeneous results. All six intervention studies found that weight gain can be mitigated by self-weighing/self-monitoring and intermittent fasting. Interventions targeting festive periods could have a significant impact on population weight gain. The scalability and sustainability of such interventions require further investigation, as do the broader socioecological factors driving unhealthy eating during festive periods.

Daily Self-Weighing to Prevent Holiday-Associated Weight Gain in Adults

OBJECTIVE

Holiday weight gain is reported to be 0.4 to 1.5 kg and may contribute to annual weight gain. The objective of this study was to test the efficacy of daily self-weighing (DSW) using visual graphical feedback (GF) to prevent holiday weight gain.

METHODS

A total of 111 adults were randomly assigned into a control or DSW + GF group and completed the preholiday visit (v1; before Thanksgiving), the postholiday visit (v2; after New Year's Day), and the follow-up visit (v3; 14 weeks after v2). The participants in the DSW + GF group performed DSW with Wi-Fi scales during the holidays and were told to try not to gain weight above baseline weight.

RESULTS

There was no change in weight with DSW + GF, whereas the control group gained weight from v1 to v2 (-0.13 ± 0.27 kg vs. 2.65 ± 0.33 kg, P < 0.001, respectively). In the control group, weight change was similar between individuals with overweight or obesity (OW/OB) versus individuals with normal weight (2.71 ± 0.48 kg vs. 2.62 ± 0.43 kg, not significant, respectively). For DSW + GF, individuals with OW/OB lost weight whereas those with normal weight maintained weight during the holidays (-1.46 ± 0.62 kg vs. 0.33 ± 0.27 kg, P = 0.01, respectively). The control group lost weight during the follow-up (-1.14 ± 0.43 kg, P = 0.01; v2 to v3) but retained 57% of weight gain; therefore, weight gain from v1 to v3 was significant (1.51 ± 0.39 kg, P < 0.001).

CONCLUSIONS

DSW + GF was a successful approach to prevent holiday weight gain, with those with OW/OB responding most favorably to DSW + GF.

Avoiding holiday seasonal weight gain with nutrient-supported intermittent energy restriction: a pilot study

This pilot randomised controlled study evaluated the effects of a nutrient-supported intermittent energy restriction nutrition programme to prevent weight gain in healthy overweight adults during the 6-week winter holiday period between Thanksgiving and New Year. For 52 d, twenty-two overweight adults (mean age 41·0 years, BMI 27·3 kg/m²) were assigned to either the nutrition programme (n 10; two fasting days of 730 kcal/d (3050 kJ/d) of balanced shake and dietary supplements to support weight management efforts, followed by 5 d of habitual diet) or a control group (n 12; habitual diet). A significant weight loss from baseline (pre-holiday 10 d before Thanksgiving) to day 52 (post-holiday 3 January) was observed in the nutrition programme (75·0 (sd 9·8) v. 76·3 (sd 9·8) kg; P < 0·05). Body weight did not significantly change in the control group and there was no between-group difference. Increases from baseline in fasting insulin (42·9 %; P = 0·0256), updated homoeostasis model assessment (HOMA2) (43 %; P = 0·025), LDL-cholesterol (8·4 %; P = 0·0426) and total cholesterol (7·1 %; P = 0·0154) levels were also reported in the control group. In the nutrition programme group, baseline HDL-cholesterol and TAG levels measured after two fasting days increased (13 %; P = 0·0245) and decreased (22·8 %; P = 0·0416), respectively. There was no significant change in HOMA2. Between-group differences in changes in insulin levels (P = 0·0227), total cholesterol:HDL-cholesterol ratio (P = 0·0419) and HOMA2 (P = 0·0210) were significant. Overall compliance rate was 98 % and no severe adverse events were reported. These preliminary findings suggest that this intermittent energy restriction intervention might support weight management efforts and help promote metabolic health during the winter holiday season.

Feasibility of Gamified Mobile Service Aimed at Physical Activation in Young Men: Population-Based Randomized Controlled Study (MOPO)

Background

The majority of young people do not meet the recommendations on physical activity for health. New innovative ways to motivate young people to adopt a physically active lifestyle are needed.

Objective

The study aimed to study the feasibility of an automated, gamified, tailored Web-based mobile service aimed at physical and social activation among young men.

Methods

A population-based sample of 496 young men (mean age 17.8 years [standard deviation 0.6]) participated in a 6-month randomized controlled trial (MOPO study). Participants were randomized to an intervention (n=250) and a control group (n=246). The intervention group was given a wrist-worn physical activity monitor (Polar Active) with physical activity feedback and access to a gamified Web-based mobile service, providing fitness guidelines, tailored health information, advice of youth services, social networking, and feedback on physical activity. Through the trial, the physical activity of the men in the control group was measured continuously with an otherwise similar monitor but providing only the time of day and no feedback. The primary outcome was the feasibility of the service based on log data and questionnaires. Among completers, we also analyzed the change in anthropometry and fitness between baseline and 6 months and the change over time in weekly time spent in moderate to vigorous physical activity.

Results

Mobile service users considered the various functionalities related to physical activity important. However, compliance of the service was limited, with 161 (64.4%, 161/250) participants visiting the service, 118 (47.2%, 118/250) logging in more than once, and 41 (16.4%, 41/250) more than 5 times. Baseline sedentary time was higher in those who uploaded physical activity data until the end of the trial (P=.02). A total of 187 (74.8%, 187/250) participants in the intervention and 167 (67.9%, 167/246) in the control group participated in the final measurements. There were no differences in the change in anthropometry and fitness from baseline between the groups, whereas waist circumference was reduced in the most inactive men within the intervention group (P=.01). Among completers with valid physical activity data (n=167), there was a borderline difference in the change in mean daily time spent in moderate to vigorous physical activity between the groups (11.9 min vs −9.1 min, P=.055, linear mixed model). Within the intervention group (n=87), baseline vigorous physical activity was inversely associated with change in moderate to vigorous physical activity during the trial (R=−.382, P=.01).

Conclusions

The various functionalities related to physical activity of the gamified tailored mobile service were considered important. However, the compliance was limited. Within the current setup, the mobile service had no effect on anthropometry or fitness, except reduced waist circumference in the most inactive men. Among completers with valid physical activity data, the trial had a borderline positive effect on moderate to vigorous physical activity. Further development is needed to improve the feasibility and adherence of an integrated multifunctional service.

Trial registration

Clinicaltrials.gov NCT01376986; http://clinicaltrials.gov/ct2/show/NCT01376986 (Archived by WebCite at http://www.webcitation.org/6tjdmIroA)

Effect of the Holiday Season on Weight Gain: A Narrative Review

Several studies suggest that the holiday season, starting from the last week of November to the first or second week of January, could be critical to gaining weight. This study aims to review the literature to determine the effects of the holidays on body weight. In studies of adults, a significant weight gain was consistently observed during this period (0.4 to 0.9 kg, p < 0.05). The only study in college students found an effect on body fat but not on weight (0.1 kg, p = 0.71). The only study found in children did not show an effect on BMI percentile (-0.4%, p > 0.05) during this period. Among individuals with obesity who attempt to lose weight, an increase in weight was observed (0.3 to 0.9 kg, significant in some but not in all studies), as well as increase in weight in motivated self-monitoring people (0.4 to 0.6%, p < 0.001). Programs focused on self-monitoring during the holidays (phone calls and daily mailing) appeared to prevent weight gain, but information is limited. The holiday season seems to increase body weight in adults, even in participants seeking to lose weight and in motivated self-monitoring people, whereas in children, adolescents, and college students, very few studies were found to make accurate conclusions.

The effect of Norouz holiday on anthropometric measures and body composition

Background

This study examined the effect of holiday season on the anthropometric measures in Shariati hospital staff.

Methods

This study was conducted in 2014 on 66 subjects, aged 21–68 years. Weight, height, waist circumference (WC), hip circumference (HC), waist -to-hip ratio (WHR), waist-to- height ratio (WHtR) and physical activity were measured. Bioelectrical impedance analysis (BIA) method and the Tanita body composition analyzer were used to analyze body composition.

Results

In this study, 80.3% of subjects were female and 19.7% were male. The mean age of subjects was 39.5 (SD: 9.7) years (range: 21–68). The percentage of overweight and obesity in the study population were 40.9% and 12.1%, respectively. After the holiday, participants gained 0.58 kg of weight and 0.19 units of BMI) P < 0.001). The average of WC, WHR and WHtR also increased after the holiday; however they were not statistically significant. Basal metabolic rate and fat free mass raised significantly, but the amount of fat mass decreased after the holiday.

Conclusion

The holiday season is a critical period for weight gain and body fat. It’s highly recommended to weight daily during the holiday season and to increase their physical activity while limiting high-calorie foods.

The effect of holiday weight gain on body weight

The topic of holiday weight gain has been a frequent subject of the lay media; however, scientific interest has only been recent. Multiple studies in Western societies have reported average weight gains among adults during the period between mid-November and mid-January that were about 0.5 kg. The range in individual weight changes was large, however, and the already overweight and obese gain more weight than those who are healthy weight. When the average gain across the year was also measured, the holiday weight was the major contributor to annual excess weight gain. Efforts patterned to increase awareness to energy balance and body weight have been shown to be successful at reducing such gain. An exception to holiday weight gain being a major contributor to annual excess gain has been children, in whom summer weight gains have been observed to be the major contributor to average excess weight gain.

The efficacy of incentives to motivate continued fitness-center attendance in college first-year students: a randomized controlled trial

OBJECTIVE

To determine whether fitness-center attendance established with the provision of weekly monetary incentives persisted after the discontinuation, or decreased frequency, of incentives.

PARTICIPANTS

One hundred seventeen first-year college students participated during the 2011-2012 academic year.

METHODS

A randomized controlled trial with control, discontinued-incentive, and continued-incentive conditions was conducted. During fall semester, students in incentive conditions received weekly monetary payments for meeting fitness-center attendance goals. During spring semester, discontinued-incentive condition participants no longer received incentives, whereas continued-incentive condition participants received payments on a variable-interval schedule. ID-card attendance records tracked fitness-center attendance.

RESULTS

Goal completion decreased from 63% in the incentive groups during the fall semester to 3% in the discontinued-incentive condition, and 39% in the continued-incentive condition during the spring semester. There was not a significant interaction between condition and body mass index change, F(6, 332) = 0.67, p = .68.

CONCLUSION

Incentive discontinuation resulted in students no longer meeting fitness-center attendance goals. A variable-interval reward schedule better maintained attendance.

Weight and body composition change over a six-week holiday period

Change in weight and body composition was assessed over a six-week holiday period. Baseline testing occurred the Monday or Tuesday prior to Thanksgiving Day (November 24 or 25, 2008), and the post-holiday assessment was the Monday or Tuesday after New Year's Day (January 5 or 6, 2009). Thirteen men and 21 women ranging in age from 23-61 years completed the study. The majority of participants (24 of 34) perceived that they had gained weight, and four did gain ≥2 kg. However, despite some changes to dietary and exercise habits, on average there was no difference between pre-holiday weight (74.0±17.8 kg) and post-holiday weight (73.9±18.1 kg), nor between pre-holiday body fat percentage (25.4±9.0%) and post-holiday body fat percentage (25.4±8.9%). Despite a perception of substantial weight gain, body weight and body fat remained unchanged over a six-week holiday period.

Set points, settling points and some alternative models: theoretical options to understand how genes and environments combine to regulate body adiposity

The close correspondence between energy intake and expenditure over prolonged time periods, coupled with an apparent protection of the level of body adiposity in the face of perturbations of energy balance, has led to the idea that body fatness is regulated via mechanisms that control intake and energy expenditure. Two models have dominated the discussion of how this regulation might take place. The set point model is rooted in physiology, genetics and molecular biology, and suggests that there is an active feedback mechanism linking adipose tissue (stored energy) to intake and expenditure via a set point, presumably encoded in the brain. This model is consistent with many of the biological aspects of energy balance, but struggles to explain the many significant environmental and social influences on obesity, food intake and physical activity. More importantly, the set point model does not effectively explain the 'obesity epidemic'--the large increase in body weight and adiposity of a large proportion of individuals in many countries since the 1980s. An alternative model, called the settling point model, is based on the idea that there is passive feedback between the size of the body stores and aspects of expenditure. This model accommodates many of the social and environmental characteristics of energy balance, but struggles to explain some of the biological and genetic aspects. The shortcomings of these two models reflect their failure to address the gene-by-environment interactions that dominate the regulation of body weight. We discuss two additional models--the general intake model and the dual intervention point model--that address this issue and might offer better ways to understand how body fatness is controlled.

Long-term increase of fat mass after a four week intervention with fast food based hyper-alimentation and limitation of physical activity

Background

A sedentary lifestyle and increased consumption of energy dense food have become more common in many parts of the world. The aim of this study was to study long term effects on body composition after a four week intervention with fast food based hyper-alimentation and limited physical activity in young normal weight subjects.

Methods

Eighteen subjects, mean age 26 (6.6) years, increased their energy intake with in average 70% and physical activity were not to exceed 5000 steps/day. Body composition was measured by Dual energy x-ray (DXA) at baseline, after the intervention and after 12 months. A matched control group was also included. ANOVA and Student's paired and unpaired t-test were used.

Results

During the intervention body weight increased with 6.4 (2.8) kg and DXA measurements showed increases of both fat free mass and fat mass. Six months after the intervention the subjects had lost most of the weight gain, - 4.7 (3.1) kg. Twelve months after the intervention body weight had increased with 1.5 (2.4) kg compared to baseline (p = 0.018). DXA measurements at 12 months showed unchanged fat free mass compared to baseline but higher fat mass, + 1.4 (1.9) kg (p = 0.01). After 2.5 years the increase of body weight was 3.1 (4.0) kg (p = 0.01) while there was no change in controls compared to baseline, + 0.1(2.5) kg (p = 0.88).

Conclusion

One year after a short term intervention with increased fast food based hyper-alimentation there was an increase of fat mass but unchanged fat free mass. As the change of fat mass was larger than expected from prospective epidemiological studies and as there was no increase of body weight in controls it raises the issue whether there is a long-term effect to increase fat mass of a short period of hyper-alimentation.

Diet composition of pregnant Finnish women: changes over time and across seasons

Objective

To describe the diet of a population of pregnant Finnish women over a period of 7 years, with special attention paid to seasonal fluctuations in food consumption and nutrient intake.

Design

A validated 181-item FFQ was applied retrospectively, after delivery, to assess the maternal diet during the 8th month of pregnancy.

Setting

Type 1 Diabetes Prediction and Prevention Nutrition Study Cohort.

Subjects

The cohort comprised a total of 4880 women who had newly delivered during the years 1997–2004, with the offspring carrying increased genetic risk for type 1 diabetes mellitus.

Results

Over the study period, the proportion of energy derived from fat decreased while the intake from protein and carbohydrate increased. The intake of vitamin D increased from food sources. Seasonal variation was observed in the mean daily consumption of vegetables, fruits and berries and cereals. Intake of dietary fibre, total fat, MUFA, vitamins A, D, E and C, folate and iron also showed seasonal fluctuation.

Conclusions

These results show an overall positive trend in the diet of pregnant Finnish women through the study years. However, there is still room for improvement, particularly in the types of dietary fats. Although food fortification with vitamin D since 2003 was reflected in the increased intake of vitamin D from foods, the mean intake levels still fell below the recommendations. Seasonal changes in food consumption were observed and related to corresponding fluctuations in nutrient intakes. The mean folate intake fell below the recommendation throughout the year.

Characterization of body weight and composition changes during the sophomore year of college

Background

Years spent in college represents a critical time for obesity development though little information is known regarding how body weight and composition changes beyond the first year of college. The aim of this study was to investigate changes in body weight and composition and the factors influencing those changes among sophomore females.

Methods

Body composition by dual energy X-ray absorptiometry was obtained in participants beginning during their freshman year and continued through their sophomore year.

Results

No difference was observed between sophomore year fall and spring visits for body weight (60.4 versus 60.6 kg) or fat mass (19.3 versus 18.7 kg). However, a significant (P ≤ 0.05) decrease was observed for body fat (31.9 versus 30.9 %fat) and a significant increase was observed for fat-free mass (37.7 versus 38.4 kg). Participants living off campus significantly (P ≤ 0.05) declined in body fat (33.0 versus 31.0 %fat) and fat mass (19.4 versus 18.2 kg) and increased in fat-free mass (36.1 versus 37.2 kg) with no differences in those living on campus.

Conclusion

No change in body weight was observed in females during their sophomore year. However, an increase in fat-free mass accompanied with a decrease in fat mass resulted in a decrease in body fat. Participants living off campus had favorable changes in their body composition by means of decreasing %fat and fat mass while increasing fat-free mass. Participants living on campus did not demonstrate these favorable changes.