Weight loss strategies for obese adults: personalized weight management program vs. standard care

‘I don't know which is the chicken and which is the egg’: A qualitative study of weight loss‐related beliefs and behaviours among adults with psoriasis and comorbid obesity

OBJECTIVES

Obesity is a common (30%-40%) comorbidity of psoriasis. Weight loss is shown to improve the severity of psoriasis; however, little is known about the factors that may influence successful weight loss in the context of obesity and psoriasis. The current qualitative study aimed to explore the obesity-associated beliefs, perceptions, and behaviours related to weight loss in psoriasis. Preferences for a weight loss intervention were also explored.

DESIGN

Qualitative in-depth semi-structured interviews were conducted with 24 adults (62.5% male) with moderate-to-severe psoriasis and obesity (mean body mass index = 35.2 kg/m² , SD = 4.1), recruited through a patient organization website in the UK. Data were analysed using inductive thematic analysis.

RESULTS

Most participants viewed psoriasis as unrelated to obesity. A well-controlled psoriasis and improvements in psoriasis symptoms were considered as major motivators for engaging in a weight loss program by individuals who viewed psoriasis and obesity as related conditions. Comfort eating was perceived as an escape strategy from the psoriasis-induced negative emotions. Participants shared their dissatisfaction with current weight loss recommendations which were too generic. They suggested that a desirable weight loss program would require both emotional and behavioural support, with an emphasis on psoriasis' burden.

CONCLUSION

The findings accentuate the importance of (1) clinicians discussing the link between obesity and psoriasis with patients, (2) weight loss advice to include both behavioural and emotional support, and (3) a weight loss advice to consider the psoriasis burden and the perceived barriers which may potentially lead to improved outcomes to obesity management in psoriasis.

Reaching high-risk Black adults for diabetes prevention programming during a pandemic: The design of Fit & Faithful a randomized controlled community trial

Obesity is a key risk factor for Type 2 diabetes (T2D). Alarmingly, 87% of US adults have overweight or obesity, with non-Hispanic black adults having higher obesity and T2D prevalence than non-Hispanic white. The Diabetes Prevention Program (DPP) demonstrated the clinical benefits of lifestyle intervention (LI). While the DPP LI is effective, some participants don't achieve clinically significant weight loss in the current group-based translation paradigm. Black adults have the lowest adjusted weight loss (3.2%) among all racial/ethnic groups. Early intervention nonresponse defined as ≤1% weight loss at intervention week 4 is linked to lower probability of achieving weight loss goals. This paper describes the design and methods of a cluster randomized controlled trial among black weight loss nonresponders nested in 20 community sites (primarily churches). Descriptions of the adaptations made to transition the program to virtual format during the COVID-19 pandemic are also included. Trained community health workers deliver a group-based, 6-month long DPP over 18 sessions via Zoom. Additionally, nonresponders in the enhanced group receive weekly telephone support to provide individual-level intervention to help overcome weight loss barriers. Outcomes include weight, physical activity level, blood pressure, and dietary behaviors; these are compared between nonresponders in the enhanced intervention group and nonresponders in the active control group. Cost, mediators, and moderators are explored. If found to efficacious, these enhanced strategies could be standardized as a supplement for use with DPP nonresponders.

Nutrition and physical activity interventions for the general population with and without cardiometabolic risk: a scoping review

OBJECTIVE

The objective of this scoping review was to examine the research question: In the adults with or without cardiometabolic risk, what is the availability of literature examining interventions to improve or maintain nutrition and physical activity-related outcomes? Sub-topics included: (1) behaviour counseling or coaching from a dietitian/nutritionist or exercise practitioner, (2) mobile applications to improve nutrition and physical activity and (3) nutritional ergogenic aids.

DESIGN

The current study is a scoping review. A literature search of the Medline Complete, CINAHL Complete, Cochrane Database of Systematic Reviews and other databases was conducted to identify articles published in the English language from January 2005 until May 2020. Data were synthesised using bubble charts and heat maps.

SETTING

Out-patient, community and workplace.

PARTICIPANTS

Adults with or without cardiometabolic risk factors living in economically developed countries.

RESULTS

Searches resulted in 19 474 unique articles and 170 articles were included in this scoping review, including one guideline, thirty systematic reviews (SR), 134 randomised controlled trials and five non-randomised trials. Mobile applications (n 37) as well as ergogenic aids (n 87) have been addressed in several recent studies, including SR. While primary research has examined the effect of individual-level nutrition and physical activity counseling or coaching from a dietitian/nutritionist and/or exercise practitioner (n 48), interventions provided by these practitioners have not been recently synthesised in SR.

CONCLUSION

SR of behaviour counseling or coaching provided by a dietitian/nutritionist and/or exercise practitioner are needed and can inform practice for practitioners working with individuals who are healthy or have cardiometabolic risk.

Inter-individual differences in body mass index were not observed as a result of aerobic exercise in children and adolescents with overweight and obesity

BACKGROUND

Exercise has been recommended as an important intervention for reducing adiposity in children and adolescents with overweight and obesity.

OBJECTIVE

Determine whether inter-individual differences exist in relation to exercise-induced changes in adiposity among children and adolescents with overweight and obesity.

METHODS

Meta-analysis of randomized controlled aerobic exercise trials and body mass index (BMI) in kg · m^-2 . Change outcome standard deviations were pooled using the inverse-variance heterogeneity model.

RESULTS

Twenty-eight studies (1185 participants) were included. Inter-individual differences in BMI were -0.1 (95% compatibility interval, -0.7 to 0.7). The 95% prediction interval for inter-individual responses in a future study was -2.9 to 2.9. The probability of a clinically meaningful difference in variability was 29% (possibly clinically important) in favour of controls vs exercisers.

CONCLUSIONS

Inter-individual differences for BMI in kg · m^-2 were not observed as a result of aerobic exercise in children and adolescents with overweight and obesity.

A Randomized Trial Evaluating Exercise for the Prevention of Weight Regain

OBJECTIVE

This study aimed to evaluate the effectiveness of three levels of exercise on weight regain subsequent to clinically meaningful weight loss (WL).

METHODS

Adults with overweight or obesity (n = 298) initiated a 3-month behavioral WL intervention, which included reduced energy intake, increased exercise, and weekly behavioral counseling. Participants achieving ≥5% WL (n = 235) began a 12-month behavioral WL maintenance intervention and were randomized to 150 min/wk (n = 76), 225 min/wk (n = 80), or 300 min/wk (n = 79) of partially supervised moderate-to-vigorous-intensity exercise.

RESULTS

Participants randomized to 150, 225, and 300 minutes of exercise completed 129 ± 30, 153 ± 49 and 179 ± 62 min/wk of exercise (supervised + unsupervised), respectively. Mean WL at 3 months (9.5 ± 3.1 kg) was similar across randomized groups (P = 0.68). Weight change across 12 months was 1.1 ± 6.5 kg, 3.2 ± 5.7 kg, and 2.8 ± 6.9 kg in the 150, 225, and 300 min/wk groups, respectively. Intent-to-treat analysis revealed no significant overall trend across the three treatment groups (P = 0.09), effects for group (P = 0.08), or sex (P = 0.21).

CONCLUSIONS

This study found no evidence for an association between the volume of moderate-to-vigorous-intensity exercise and weight regain across 12 months following clinically relevant WL. Further, results suggest that exercise volumes lower than those currently recommended for WL maintenance, when completed in conjunction with a behavioral weight-maintenance intervention, may minimize weight regain over 12 months.

Effects of Self-Weighing During Weight Loss Treatment: A 6-Month Randomized Controlled Trial

Objective

To examine the effectiveness of self-weighing for weight loss in men for 6 months.

Methods

In the present study, 54 men, mean age of 40.1 ± 11.1 years, with overweight or obesity, were recruited and randomly assigned into two groups: control group (CG), without weight self-monitoring and intervention group (IG), with weight self-monitoring. Both groups received the same nutritional and educational advice and the establishment of a weight target to reach in the weight loss program. Subjects of IG also had individualized motivating content to improve self-management for 24 weeks. Anthropometric indices were measured at baseline and weekly for 24 weeks.

Results

When the group assigned after randomization was introduced in the analysis, its influence was significant in weight loss (F1.52 = 19.465, ± 2 = 0.272, p < 0.001) and in the decrease in body fat percentage (F1.52 = 8,306, ± 2 = 0.132, p < 0.01).

Conclusion

Study results indicate that self-weighing can help patients to lose additional weight. Our findings have implications in the emerging area of the behavioral approach of patients undergoing weight-loss treatment, as well as clinical care processes.

Clinical Trial Registration

www.ClinicalTrials.gov, identifier NCT04032249.

Association of Food Access, Recreational Opportunities, and Natural Amenities with Engagement in the Veterans MOVE! Weight Management Program

OBJECTIVE

The aim of this study was to examine the association of county-level food access, recreational opportunities, and natural amenities with participant engagement in a weight management program.

METHODS

In this cohort study, participants in the Veterans Health Administration MOVE! weight management program between October 1, 2007, and September 30, 2013, were observed for 12 months after enrollment. Engagement was measured as the number of program visits per year at 12 months. Cross-sectional analysis and spatial regression were used to examine county characteristics associated with greater participant engagement at 12 months.

RESULTS

A total of 321,624 participants in 2,708 counties were included. Greater engagement was associated with older age, female sex, white race, being married, and being retired. After accounting for similarities between nearby communities, engagement at 12 months was 3.1 visits higher for each additional farmers' market per 1,000 population (P = 0.01). Engagement was highest for participants living in counties with the most natural amenities (P < 0.001). Recreational opportunities had only a small effect on engagement in the program (β = 0.02 visits at 12 months; P = 0.002).

CONCLUSIONS

Consideration of a participant's county characteristics in addition to other known demographics and program factors may help to explain variation in engagement in weight management programs.

Changes in body composition with a hypocaloric diet combined with sedentary, moderate and high-intense physical activity: a randomized controlled trial

BACKGROUND

There is evidence showing the effectiveness of a hypocaloric diet and the increase in physical activity on weight loss. However, the combined role of these factors, not only on weight loss but also body composition, remains unclear. The purpose of this study was to investigate the effect of a hypocaloric diet on the body composition of obese adult women throughout different degrees of physical activity during a weight loss program.

METHODS

One hundred and seventeen healthy female volunteers were randomly assigned to one of the experimental groups: a control group with a low-level prescription of physical activity (1-4 METs), moderate physical activity group that performed 10.000 steps walking (5-8 METs) and intense physical activity group that trained exercises by at least 70% of VO2max three times a week (> 8 METs). All subjects followed a hypocaloric diet designed with a reduction of 500 kcal/day. Nutritional counseling was provided throughout the study period to help ensure dietary adherence.

RESULTS

We found no differences in body weight compared to moderate and intense physical activity (ßstand. = - 0.138 vs. ßstand. = - 0.139). Body fat was lower in women following an intense activity (ßstand. = - 0.436) than those with moderate exercise (ßstand. = - 0.231). The high-intense activity also increased muscle mass at the end of the intervention, standing out above the moderate activity (ßstand. = 0.182 vs. ßstand. = 0.008).

CONCLUSIONS

These findings indicate that a hypocaloric diet, without prescription of physical activity, is adequate to lose weight in the short term (12 weeks), but physical activity is vital to modify the body composition in women with obesity. Body fat was lower when women practiced a moderate exercise compared to hypocaloric diet only, but an intense physical activity was the most effective protocol to obtain a reduction of body fat and maintain muscle mass.

TRIAL REGISTRATION

The study protocol complied with the Declaration of Helsinki for medical studies, it was approved by the bioethical committee of Córdoba University, in the Department of Health at the Regional Government of Andalusia (Act n°284, ref.4156) and retrospectively registered in clinicaltrials.gov (NCT03833791). Registered 2 January 2019.

Effect of Weight Loss via Severe vs Moderate Energy Restriction on Lean Mass and Body Composition Among Postmenopausal Women With Obesity: The TEMPO Diet Randomized Clinical Trial

IMPORTANCE

Severely energy-restricted diets are the most effective dietary obesity treatment. However, there are concerns regarding potential adverse effects on body composition.

OBJECTIVE

To compare the long-term effects of weight loss via severe vs moderate energy restriction on lean mass and other aspects of body composition.

DESIGN, SETTING, AND PARTICIPANTS

The Type of Energy Manipulation for Promoting Optimum Metabolic Health and Body Composition in Obesity (TEMPO) Diet Trial was a 12-month, single-center, randomized clinical trial. A total of 101 postmenopausal women, aged 45 to 65 years with body mass index (calculated as weight in kilograms divided by height in meters squared) from 30 to 40, who were at least 5 years after menopause, had fewer than 3 hours of structured physical activity per week, and lived in the Sydney metropolitan area of New South Wales, Australia, were recruited between March 2013 and July 2016. Data analysis was conducted between October 2018 and August 2019.

INTERVENTION

Participants were randomized to either 12 months of moderate (25%-35%) energy restriction with a food-based diet (moderate intervention) or 4 months of severe (65%-75%) energy restriction with a total meal replacement diet followed by moderate energy restriction for an additional 8 months (severe intervention). Both interventions had a prescribed protein intake of 1.0 g/kg of actual body weight per day, and physical activity was encouraged but not supervised.

MAIN OUTCOMES AND MEASURES

The primary outcome was whole-body lean mass at 12 months after commencement of intervention. Secondary outcomes were body weight, thigh muscle area and muscle function (strength), bone mineral density, and fat mass and distribution, measured at 0, 4, 6, and 12 months.

RESULTS

A total of 101 postmenopausal women were recruited (mean [SD] age, 58.0 [4.2] years; mean [SD] weight, 90.8 [9.1] kg; mean [SD] body mass index, 34.4 [2.5]). Compared with the moderate group at 12 months, the severe group lost more weight (effect size, -6.6 kg; 95% CI, -8.2 to -5.1 kg), lost more whole-body lean mass (effect size, -1.2 kg; 95% CI, -2.0 to -0.4 kg), and lost more thigh muscle area (effect size, -4.2 cm2; 95% CI, -6.5 to -1.9 cm2). However, decreases in whole-body lean mass and thigh muscle area were proportional to total weight loss, and there was no difference in muscle (handgrip) strength between groups. Total hip bone mineral density (effect size, -0.017 g/cm2; 95% CI, -0.029 to -0.005 g/cm2), whole-body fat mass (effect size, -5.5 kg; 95% CI, -7.1 to -3.9 kg), abdominal subcutaneous adipose tissue (effect size, -1890 cm3; 95% CI, -2560 to -1219 cm3), and visceral adipose tissue (effect size, -1389 cm3; 95% CI, -1748 to -1030 cm3) loss were also greater for the severe group than for the moderate group at 12 months.

CONCLUSIONS AND RELEVANCE

Severe energy restriction had no greater adverse effect on relative whole-body lean mass or handgrip strength compared with moderate energy restriction and was associated with 2-fold greater weight and fat loss over 12 months. However, there was significantly greater loss of total hip bone mineral density with severe vs moderate energy restriction. Therefore, caution is necessary when implementing severe energy restriction in postmenopausal women, particularly those with osteopenia or osteoporosis.

TRIAL REGISTRATION

anzctr.org.au Identifier: 12612000651886.

Dynamic Macronutrient Meal-Equivalent Menu Method: Towards Individual Nutrition Intervention Programs

Nutrition interventions should reflect the state of the art in science and dietetics to meet each patient’s requirements. Incorporating new knowledge into individualized food-based nutrition interventions is a major challenge, and health care professionals constantly search for novel approaches through specific and standardized methods. The dynamic macronutrient meal-equivalent menu method involves individuals making informed food choices that match their requirements, schedule, and food availability and affinity, helping them maintain a sense of control and motivation to adhere to a nutrition intervention program. This protocol includes the steps required to prepare a nutrition plan containing equivalent meal options consistent with the patient’s needs and preferences. Standard food servings are planned according to population specific dietary guidelines and individual characteristics. Servings are distributed at required mealtimes, and are all equivalent in energy and macronutrient content, providing every patient with interchangeable choices within each mealtime. This empowers individuals to select foods in a guided format whilst adhering to a dietary plan. Acceptable variations for calculated energy and macronutrient content are as follows: protein ±1 g/day, fat ±1 g/day, carbohydrate ±2 g/day, and energy ±15 kcal/day. Following this method, health care professionals can develop individualized nutrition intervention programs that may improve patients’ adherence, nutritional status, and health.

Dynamic Energy Balance and Obesity Prevention

Dynamic energy balance can give clinicians important answers for why obesity is so resistant to control. When food intake is reduced for weight control, all components of energy expenditure change, including metabolic rate at rest (resting energy expenditure [REE]), metabolic rate of exercise, and adaptive thermogenesis. This means that a change in energy intake influences energy expenditure in a dynamic way. Mechanisms associated with reduction of total energy expenditure following weight loss are likely to be related to decreased body mass and enhanced metabolic efficiency. Reducing calorie intake results in a decrease in body weight, initially with a marked reduction in fat free mass and a decrease in REE, and this change is maintained for several years in a reduced state. Metabolic adaptation, which is not explained by changes in body composition, lasts for more than several years. These are powerful physiological adaptations that induce weight regain. To avoid a typically observed weight-loss and regain trajectory, realistic weight loss goals should be established and maintained for more than 1 year. Using a mathematical model can help clinicians formulate advice about diet control. It is important to emphasize steady efforts for several years to maintain reduced weight over efforts to lose weight. Because obesity is difficult to reverse, clinicians must prioritize obesity prevention. Obesity prevention strategies should have high feasibility, broad population reach, and relatively low cost, especially for young children who have the smallest energy gaps to change.

How much exercise should be promoted to raise total daily energy expenditure and improve health?

Despite longstanding recognition of the benefits of a physically active lifestyle, there remains ambiguity regarding exactly how much exercise should be promoted to raise total energy expenditure (TEE) and improve health. This review provides a brief summary of the dose-response relationship between physical activity and relative risk of morbidity and mortality; mechanisms through which exercise drives an increase in TEE; the highest reported levels of TEE measured via doubly labelled water; and the potential impact of non-compliance and confounders in moderating the contribution of exercise to increase TEE. Cohort studies provide a compelling argument that 'more is better' regarding the exercise dose for increasing TEE, that increasing TEE is protective for health, and that this is mediated through increased cardiorespiratory fitness. However, growing evidence shows that ever increasing volumes of weekly physical activity may reverse the cost-benefit seen with more modest doses. Animal and human studies show that the elevation in TEE associated with increasing exercise volume is commonly less than expected, due to physiological confounders. Further, there is considerable evidence of behavioural non-compliance to planned exercise in all but the most highly motivated athletes. Therefore, inbuilt defence mechanisms may safeguard against TEE being elevated to maximum levels.

Rationale and Protocol for a Randomized Controlled Trial Comparing Fast versus Slow Weight Loss in Postmenopausal Women with Obesity-The TEMPO Diet Trial

Very low energy diets (VLEDs), commonly achieved by replacing all food with meal replacement products and which result in fast weight loss, are the most effective dietary obesity treatment available. VLEDs are also cheaper to administer than conventional, food-based diets, which result in slow weight loss. Despite being effective and affordable, these diets are underutilized by healthcare professionals, possibly due to concerns about potential adverse effects on body composition and eating disorder behaviors. This paper describes the rationale and detailed protocol for the TEMPO Diet Trial (Type of Energy Manipulation for Promoting optimal metabolic health and body composition in Obesity), in a randomized controlled trial comparing the long-term (3-year) effects of fast versus slow weight loss. One hundred and one post-menopausal women aged 45–65 years with a body mass index of 30–40 kg/m² were randomized to either: (1) 16 weeks of fast weight loss, achieved by a total meal replacement diet, followed by slow weight loss (as for the SLOW intervention) for the remaining time up until 52 weeks (“FAST” intervention), or (2) 52 weeks of slow weight loss, achieved by a conventional, food-based diet (“SLOW” intervention). Parameters of body composition, cardiometabolic health, eating disorder behaviors and psychology, and adaptive responses to energy restriction were measured throughout the 3-year trial.

Recruitment Strategies for a Randomised Controlled Trial Comparing Fast Versus Slow Weight Loss in Postmenopausal Women with Obesity-The TEMPO Diet Trial

Current research around effective recruitment strategies for clinical trials of dietary obesity treatments have largely focused on younger adults, and thus may not be applicable to older populations. The TEMPO Diet Trial (Type of Energy Manipulation for Promoting optimal metabolic health and body composition in Obesity) is a randomised controlled trial comparing the long-term effects of fast versus slow weight loss on body composition and cardio-metabolic health in postmenopausal women with obesity. This paper addresses the recruitment strategies used to enrol participants into this trial and evaluates their relative effectiveness. 101 post-menopausal women aged 45–65 years, with a body mass index of 30–40 kg/m² were recruited and randomised to either fast or slow weight loss. Multiple strategies were used to recruit participants. The total time cost (labour) and monetary cost per randomised participant from each recruitment strategy was estimated, with lower values indicating greater cost-effectiveness and higher values indicating poorer cost-effectiveness. The most cost-effective recruitment strategy was word of mouth, followed (at equal second place) by free publicity on TV and radio, and printed advertorials, albeit these avenues only yielded 26/101 participants. Intermediate cost-effective recruitment strategies were flyer distribution at community events, hospitals and a local tertiary education campus, internet-based strategies, and clinical trial databases and intranets, which recruited a further 40/101 participants. The least cost-effective recruitment strategy was flyer distribution to local health service centres and residential mailboxes, and referrals from healthcare professionals were not effective. Recruiting for clinical trials involving postmenopausal women could benefit from a combination of recruitment strategies, with an emphasis on word of mouth and free publicity via radio, TV, and print media, as well as strategic placement of flyers, supplemented with internet-based strategies, databases and intranets if a greater yield of participants is needed.

Effects of a 12-week aerobic exercise intervention on eating behaviour, food cravings, and 7-day energy intake and energy expenditure in inactive men

This study examined effects of 12 weeks of moderate-intensity aerobic exercise on eating behaviour, food cravings, and weekly energy intake and expenditure in inactive men. Eleven healthy men (mean ± SD: age, 26 ± 5 years; body mass index, 24.6 ± 3.8 kg·m^-2; maximum oxygen uptake, 43.1 ± 7.4 mL·kg^-1·min^-1) completed the 12-week supervised exercise programme. Body composition, health markers (e.g., blood pressure), eating behaviour, food cravings, and weekly energy intake and expenditure were assessed before and after the exercise intervention. There were no intervention effects on weekly free-living energy intake (p = 0.326, d = -0.12) and expenditure (p = 0.799, d = 0.04) or uncontrolled eating and emotional eating scores (p > 0.05). However, there was a trend with a medium effect size (p = 0.058, d = 0.68) for cognitive restraint to be greater after the exercise intervention. Total food cravings (p = 0.009, d = -1.19) and specific cravings of high-fat foods (p = 0.023, d = -0.90), fast-food fats (p = 0.009, d = -0.71), and carbohydrates/starches (p = 0.009, d = -0.56) decreased from baseline to 12 weeks. Moreover, there was a trend with a large effect size for cravings of sweets (p = 0.052, d = -0.86) to be lower after the exercise intervention. In summary, 12 weeks of moderate-intensity aerobic exercise reduced food cravings and increased cognitive restraint, but these changes were not accompanied by changes in other eating behaviours or weekly energy intake and expenditure. The results indicate the importance of exercising for health improvements even when reductions in body mass are modest.

Using new technologies to promote weight management: a randomised controlled trial study protocol

Background

Over the last three decades, overweight and obesity and the associated health consequences have become global public health priorities. Methods that have been tried to address this problem have not had the desired impact, suggesting that other approaches need to be considered. One of the lessons learned throughout these attempts is that permanent weight loss requires sustained dietary and lifestyle changes, yet adherence to weight management programs has often been noted as one of the biggest challenges. This trial aims to address this issue by examining whether social media, as a potential health promotion tool, will improve adherence to a weight management program. To test the effectiveness of this measure, the designated program will be delivered via the popular social networking site Facebook, and compared to a standard delivery method that provides exactly the same content but which is communicated through a pamphlet. The trial will be conducted over a period of twelve weeks, with a twelve week follow-up. Although weight loss is expected, this study will specifically investigate the effectiveness of social media as a program delivery method. The program utilised will be one that has already been proven to achieve weight loss, namely The CSIRO Total Wellbeing Diet.

Methods/design

This project will be conducted as a 3-arm randomised controlled trial. One hundred and twenty participants will be recruited from the Perth community, and will be randomly assigned to one of the following three groups: the Facebook group, the pamphlet group, or a control group. The Facebook Group will receive the weight management program delivered via a closed group in Facebook, the Pamphlet Group will be given the same weight management program presented in a booklet, and the Control Group will follow the Australian Dietary Guidelines and the National Physical Activity Guidelines for Adults as usual care. Change in weight, body composition and waist circumference will be initial indicators of adherence to the program. Secondary outcome measures will be blood glucose, insulin, blood pressure, arterial stiffness, physical activity, eating behaviour, mental well-being (stress, anxiety, and depression), social support, self-control, self-efficacy, Facebook activity, and program evaluation.

Discussion

It is expected that this trial will support the use of social media - a source of social support and information sharing - as a delivery method for weight management programs, enhancing the reduction in weight expected from dietary and physical activity changes. Facebook is a popular, easy to access and cost-effective online platform that can be used to assist the formation of social groups, and could be translated into health promotion practice relatively easily. It is anticipated in the context of the predicted findings that social media will provide an invaluable resource for health professionals and patients alike.

Trial registration

Australian New Zealand Clinical Trials Register (ANZCTR): ACTRN12614000536662. Date registered: 21 May 2014.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-015-1849-4) contains supplementary material, which is available to authorized users.

Effectiveness of weight loss interventions--is there a difference between men and women: a systematic review

Effective strategies are required to reduce the prevalence of overweight and obesity; however, the effectiveness of current weight loss programmes is variable. One contributing factor may be the difference in weight loss success between men and women. A systematic review was conducted to determine whether the effectiveness of weight loss interventions differs between men and women. Randomized controlled trials published up until March 2014 were included. Effect sizes (Hedges' g) were used to examine the difference in weight outcomes between men and women. A total of 58 studies met the eligibility criteria with 49 studies of higher quality included in the final data synthesis. Eleven studies that directly compared weight loss in men and women reported a significant sex difference. Ten of these reported that men lost more weight than women; however, women also lost a significant amount of weight. Analysis of effect sizes found small differences in weight loss favouring men for both diet (g = 0.489) and diet plus exercise (g = 0.240) interventions. There is little evidence from this review to indicate that men and women should adopt different weight loss strategies. Current evidence supports moderate energy restriction in combination with exercise for weight loss in both men and women.

Self-help for weight loss in overweight and obese adults: systematic review and meta-analysis

We conducted a systematic review and meta-analysis investigating the components and effectiveness of self-help weight-loss interventions and their applicability to less-advantaged populations. We searched (November 2013) for randomized controlled trials comparing self-help interventions with each other or with minimal controls in overweight and obese adults, with 6 months or longer follow-up. We calculated mean difference between intervention and control for 6- and 12-month weight change. Twenty-three studies met the inclusion criteria (9632 participants; 39 intervention arms). Intervention participants lost significantly more weight than controls at 6 months (mean difference -1.85 kg; 95% confidence interval [CI]=-2.86, -0.83; 7 studies). No significant effect was detected at 12 months but results were sensitive to the inclusion of 1 study at high risk of bias. Interactive programs appeared more effective than standard ones at 6 months (mean difference -0.94 kg; 95% CI=-1.50, -0.38). Evidence is insufficient to reach conclusions on effectiveness in socioeconomically disadvantaged people, but suggests self-help interventions may be less effective in this group.

A Dyadic Action Control Trial in Overweight and Obese Couples (DYACTIC)

Background

Enhancing physical activity in overweight and obese individuals is an important means to promote health in this target population. The Health Action Process Approach (HAPA), which was the theoretical framework of this study, focuses on individual self-regulation variables for successful health behavior change. One key self-regulation variable of this model is action control with its three subfacets awareness of intentions, self-monitoring and regulatory effort. The social context of individuals, however, is usually neglected in common health behavior change theories. In order to integrate social influences into the HAPA, this randomized controlled trial investigated the effectiveness of a dyadic conceptualization of action control for promoting physical activity.

Methods/Design

This protocol describes the design of a single-blind randomized controlled trial, which comprises four experimental groups: a dyadic action control group, an individual action control group and two control groups. Participants of this study are overweight or obese, heterosexual adult couples who intend to increase their physical activity. Blocking as means of a gender-balanced randomization is used to allocate couples to conditions and partners to either being the target person of the intervention or to the partner condition. The ecological momentary intervention takes place in the first 14 days after baseline assessment and is followed by another 14 days diary phase without intervention. Follow-ups are one month and six months later. Subsequent to the six-months follow-up another 14 days diary phase takes place.

The main outcome measures are self-reported and accelerometer-assessed physical activity. Secondary outcome measures are Body Mass Index (BMI), aerobic fitness and habitual physical activity.

Discussion

This is the first study examining a dyadic action control intervention in comparison to an individual action control condition and two control groups applying a single-blind randomized control trial. Challenges with running couples studies as well as advantages and disadvantages of certain design-related decisions are discussed. This RCT was funded by the Swiss National Science Foundation (PP00P1_133632/1) and was registered on 27/04/2012 at http://www.isrctn.com/ISRCTN15705531.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2458-14-1321) contains supplementary material, which is available to authorized users.

Measuring outcomes in adult weight loss studies that include diet and physical activity: a systematic review

Background. Measuring success of obesity interventions is critical. Several methods measure weight loss outcomes but there is no consensus on best practices. This systematic review evaluates relevant outcomes (weight loss, BMI, % body fat, and fat mass) to determine which might be the best indicator(s) of success. Methods. Eligible articles described adult weight loss interventions that included diet and physical activity and a measure of weight or BMI change and body composition change. Results. 28 full-text articles met inclusion criteria. Subjects, settings, intervention lengths, and intensities varied. All studies measured body weight (−2.9 to −17.3 kg), 9 studies measured BMI (−1.1 to −5.1 kg/m²), 20 studies measured % body fat (−0.7 to −10.2%), and 22 studies measured fat mass (−0.9 to −14.9 kg). All studies found agreement between weight or BMI and body fat mass or body fat % decreases, though there were discrepancies in degree of significance between measures. Conclusions. Nearly all weight or BMI and body composition measures agreed. Since body fat is the most metabolically harmful tissue type, it may be a more meaningful measure of health change. Future studies should consider primarily measuring % body fat, rather than or in addition to weight or BMI.

Fat oxidation over a range of exercise intensities: fitness versus fatness

Maximal fat oxidation (MFO), as well as the exercise intensity at which it occurs (Fatmax), have been reported as lower in sedentary overweight individuals but have not been studied in trained overweight individuals. The aim of this study was to compare Fatmax and MFO in lean and overweight recreationally trained males matched for cardiorespiratory fitness (CRF) and to study the relationships between these variables, anthropometric characteristics, and CRF. Twelve recreationally trained overweight (high fatness (HiFat) group, 30.0% ± 5.3% body fat) and 12 lean males (low fatness (LoFat), 17.2% ± 5.7% body fat) matched for CRF (maximal oxygen consumption (V̇O2max) 39.0 ± 5.5 vs. 41.4 ± 7.6 mL·kg(-1)·min(-1), p = 0.31) and age (p = 0.93) performed a graded exercise test on a cycle ergometer. V̇O2max and fat and carbohydrate oxidation rates were determined using indirect calorimetry; Fatmax and MFO were determined with a mathematical model (SIN); and % body fat was assessed by air displacement plethysmography. MFO (0.38 ± 0.19 vs. 0.42 ± 0.16 g·min(-1), p = 0.58), Fatmax (46.7% ± 8.6% vs. 45.4% ± 7.2% V̇O2max, p = 0.71), and fat oxidation rates over a wide range of exercise intensities were not significantly different (p > 0.05) between HiFat and LoFat groups. In the overall cohort (n = 24), MFO and Fatmax were correlated with V̇O2max (r = 0.46, p = 0.02; r = 0.61, p = 0.002) but not with % body fat or body mass index (p > 0.05). Fat oxidation during exercise was similar in recreationally trained overweight and lean males matched for CRF. Consistently, substrate oxidation rates during exercise were not related to adiposity (% body fat) but were related to CRF. The benefits of high CRF independent of body weight and % body fat should be further highlighted in the management of obesity.

Personal health technologies in employee health promotion: usage activity, usefulness, and health-related outcomes in a 1-year randomized controlled trial

BACKGROUND

Common risk factors such as obesity, poor nutrition, physical inactivity, stress, and sleep deprivation threaten the wellness and work ability of employees. Personal health technologies may help improve engagement in health promotion programs and maintenance of their effect.

OBJECTIVE

This study investigated personal health technologies in supporting employee health promotion targeting multiple behavioral health risks. We studied the relations of usage activity to demographic and physiological characteristics, health-related outcomes (weight, aerobic fitness, blood pressure and cholesterol), and the perceived usefulness of technologies in wellness management.

METHODS

We conducted a subgroup analysis of the technology group (114 subjects, 33 males, average age 45 years, average BMI 27.1 kg/m(2)) of a 3-arm randomized controlled trial (N=352). The trial was organized to study the efficacy of a face-to-face group intervention supported by technologies, including Web services, mobile applications, and personal monitoring devices. Technology usage was investigated based on log files and questionnaires. The associations between sustained usage of Web and mobile technologies and demographic and physiological characteristics were analyzed by comparing the baseline data of sustained and non-sustained users. The associations between sustained usage and changes in health-related outcomes were studied by repeated analysis of variance, using data measured by baseline and end questionnaires, and anthropometric and laboratory measurements. The experienced usability, usefulness, motivation, and barriers to using technologies were investigated by 4 questionnaires and 2 interviews.

RESULTS

111 subjects (97.4%) used technologies at some point of the study, and 33 (29.9%) were classified as sustained users of Web or mobile technologies. Simple technologies, weight scales and pedometer, attracted the most users. The sustained users were slightly older 47 years (95% CI 44 to 49) versus 44 years (95% CI 42 to 45), P=.034 and had poorer aerobic fitness at baseline (mean difference in maximal metabolic equivalent 1.0, 95% Cl 0.39 to 1.39; P=.013) than non-sustained users. They succeeded better in weight management: their weight decreased -1.2 kg (95% CI -2.38 to -0.01) versus +0.6 kg (95% CI -0.095 to 1.27), P=.006; body fat percentage -0.9%-units (95% CI -1.64 to -0.09) versus +0.3%-units (95% CI -0.28 to 0.73), P=.014; and waist circumference -1.4 cm (95% CI -2.60 to -0.20) versus +0.7 cm (95% CI -0.21 to 1.66), P=.01. They also participated in intervention meetings more actively: median 4 meetings (interquartile range; IQR 4-5) versus 4 meetings (IQR 3-4), P=.009. The key factors in usefulness were: simplicity, integration into daily life, and clear feedback on progress.

CONCLUSIONS

Despite active initial usage, less than 30% of subjects continued using Web or mobile technologies throughout the study. Sustained users achieved better weight-related outcomes than non-sustained users. High non-usage attrition and modest outcomes cast doubt on the potential of technologies to support interventions.

Can a weight loss of one pound a week be achieved with a 3500-kcal deficit? Commentary on a commonly accepted rule

Despite theoretical evidence that the model commonly referred to as the 3500-kcal rule grossly overestimates actual weight loss, widespread application of the 3500-kcal formula continues to appear in textbooks, on respected government- and health-related websites, and scientific research publications. Here we demonstrate the risk of applying the 3500-kcal rule even as a convenient estimate by comparing predicted against actual weight loss in seven weight loss experiments conducted in confinement under total supervision or objectively measured energy intake. We offer three newly developed, downloadable applications housed in Microsoft Excel and Java, which simulates a rigorously validated, dynamic model of weight change. The first two tools available at http://www.pbrc.edu/sswcp, provide a convenient alternative method for providing patients with projected weight loss/gain estimates in response to changes in dietary intake. The second tool, which can be downloaded from the URL http://www.pbrc.edu/mswcp, projects estimated weight loss simultaneously for multiple subjects. This tool was developed to inform weight change experimental design and analysis. While complex dynamic models may not be directly tractable, the newly developed tools offer the opportunity to deliver dynamic model predictions as a convenient and significantly more accurate alternative to the 3500-kcal rule.

Physical activity and circulating endothelial progenitor cells: an intervention study

BACKGROUND

To assess the effect of a personalized physical activity programme on weight and circulating (CPC) and endothelial progenitor cells (EPC) in overweight and obese subjects.

MATERIALS AND METHODS

Anthropometric measurements with body composition, cardiopulmonary test, maximal stress exercise test with maximal oxygen uptake (VO(2max) ) and a series of biochemical analyses were taken before (T0) and after 3 months of physical activity (T1) in a total of 80 overweight and obese subjects. CPC and EPC were determined using flow cytometry and were defined as CD34+, CD133+ and CD34+/CD133+ for CPC and CD34+KDR+, CD133+KDR+ and CD34+CD133+KDR+ for EPC.

RESULTS

At the end of the programme, we divided the population into two groups, compliant individuals (group A, n = 47) and noncompliant individuals (group B, n = 33). Group A reported significant reductions of weight by 3·1% (P < 0·0001) and fat mass by 4·4% (P < 0·0001), while group B showed a percentage of increase in fat mass by 1·5% at T1. In group A, a trend of increase at T1 for circulating levels of CPC and EPC was observed, reaching the statistical significance for all the three types of EPC. On the contrary, group B showed no significant increase in CPC and EPC. Furthermore, a significant correlation between decrease in fat mass and increase in CD133+/KDR+ EPC was reported in group A (r = 0·50; P = 0·04).

CONCLUSION

Three months of physical activity significantly improved anthropometric measurements. A beneficial effect of increased number of EPC in compliant individuals, in relation to weight loss, was observed.

Comparative assessment of change in fat mass using dual X-ray absorptiometry and air-displacement plethysmography

OBJECTIVE

To compare the accuracy of body composition measurements to small, defined changes in fat mass between dual X-ray absorptiometry (DXA) and air-displacement plethysmography (ADP).

METHODS

Fifty-six healthy adults, 29 women and 27 men (age, 38 ± 12.4 years; BMI, 27.6 ± 5.8 kg/m²) were included in the study. Exclusion criteria were pregnancy, indwelling metal hardware or pacemakers, or weight exceeding DXA table limit (>350 lbs). All individual testing was completed within a 2-hour period. Fat packets were prepared using lard wrapped in plastic and applied exogenously in defined locations. Each participant completed body composition measurements with ADP and DXA (both testing modalities completed with and without 1 kg of exogenously applied fat mass).

RESULTS

Both DXA and ADP were highly accurate in detecting an overall increase in body mass associated with exogenously applied 1kg of fat mass (0.99 kg vs. 0.97 kg, respectively). DXA more accurately detected exogenous fat increase as fat mass compared to ADP (0.93 kg; 90% CI for the mean of the difference: 0.83 to 1.03 kg vs. 0.45 kg; 90% CI: 0.19 to 0.71 kg, respectively). The accuracy of body mass detection was similar for males and females (0.97 vs. 1.02 for DXA and 0.92 vs. 1.02 for ADP, respectively), though accuracy in detecting added mass as fat was less accurate in males than females (0.84 vs. 1.00 for DXA and 0.39 vs. 0.51 for ADP, respectively).

DISCUSSION

Both DXA and ADP are accurate in detecting an overall increase in body mass associated with exogenously applied 1kg of fat mass. However, DXA is more accurate than ADP in correctly identifying the increase in body mass as fat mass, as opposed to fat free mass.

Role of apathy in the effectiveness of weight management programmes

AIMS

Obesity, which is at epidemic proportions in the USA, is associated with a higher risk of several co-morbid diseases including, cardiovascular disease, cancer and sleep apnea. Weight loss and weight maintenance programmmes are difficult to sustain for long term. Mental health problems such as apathy may be a major factor in patients unsuccessful in adhering to weight loss programmes. We propose that treating apathy will result in better weight loss in obese patients.

METHODS

This was a randomized prospective pilot study. Obese patients (n = 101) were randomized in a 1:2:2 ratio to either (i) standard nutrition counselling; or (ii) the Department of Veterans Affairs weight loss programme called 'motivate obese veterans everywhere ' (MOVE); or (iii) methylphenidate treatment plus the MOVE programme together. The intervention was for 6 months (26 weeks).

RESULTS

For the within groups analysis, the absolute changes in weight (kg) are as follows, for MOVE (mean: -1.84; 95% confidence interval (CI): -4.56 to 0.87; p = 0.25), Methylphenidate (mean: -4.61; 95% CI: -7.90 to -1.33; p = 0.04), standard nutrition counselling (mean: -0.60; 95% CI: -2.59 to 1.39; p = 0.21), which indicates that although all three groups lost weight, only the methylphenidate group achieved statistical significance. The between group differences of the relative change in weight were not statistically different. The apathy evaluation score and the patient activation measure improved in all groups.

CONCLUSION

Together these data suggest that treating apathy might be an important factor in the success of weight management programmes.

Computerized self-monitoring and technology-assisted feedback for weight loss with and without an enhanced behavioral component

OBJECTIVE

The purpose of this study was to develop and evaluate a 12-week weight management intervention involving computerized self-monitoring and technology-assisted feedback with and without an enhanced behavioral component.

METHODS

120 overweight (30.5±2.6kg/m(2)) adults (45.0±10.3 years) were randomized to one of three groups: computerized self-monitoring with Basic feedback (n=45), Enhanced behavioral feedback (n=45), or wait-list control (n=30). Intervention participants used a computer software program to record dietary and physical activity information. Weekly e-mail feedback was based on computer-generated reports, and participants attended monthly measurement visits.

RESULTS

The Basic and Enhanced groups experienced significant weight reduction (-2.7±3.3kg and -2.5±3.1kg) in comparison to the Control group (0.3±2.2; p<0.05). Waist circumference and systolic blood pressure also decreased in intervention groups compared to Control (p<0.01).

CONCLUSIONS

A program using computerized self-monitoring, technology-assisted feedback, and monthly measurement visits produced significant weight loss after 12 weeks. However, the addition of an enhanced behavioral component did not improve the effectiveness of the program.

PRACTICE IMPLICATIONS

This study suggests that healthcare professionals can effectively deliver a weight management intervention using technology-assisted strategies in a format that may complement and reduce face-to-face sessions.

Usual and unusual care: existing practice control groups in randomized controlled trials of behavioral interventions

OBJECTIVE

To evaluate the use of existing practice control groups in randomized controlled trials of behavioral interventions and the role of extrinsic health care services in the design and conduct of behavioral trials.

METHOD

Selective qualitative review.

RESULTS

Extrinsic health care services, also known as nonstudy care, have important but under-recognized effects on the design and conduct of behavioral trials. Usual care, treatment-as-usual, standard of care, and other existing practice control groups pose a variety of methodological and ethical challenges, but they play a vital role in behavioral intervention research.

CONCLUSIONS

This review highlights the need for a scientific consensus statement on control groups in behavioral trials.

Exercise-induced energy expenditure: implications for exercise prescription and obesity

OBJECTIVE

Walking is commonly recommended to help with weight management. We measured total energy expenditure (TEE) and its components to quantify the impact of increasing exercise-induced energy expenditure (ExEE) on other components of TEE.

METHODS

Thirteen obese women underwent an 8-week walking group intervention. TEE was quantified using doubly labeled water, ExEE was quantified using heart rate monitors, daily movement was assessed by accelerometry and resting metabolic rate was measured using indirect calorimetry.

RESULTS

Four of the 13 participants achieved the target of 1500kcalwk(-1) of ExEE and all achieved 1000kcalwk(-1). The average ExEE achieved by the group across the 8 weeks was 1434+/-237kcalwk(-1). Vigorous physical activity, as assessed by accelerometry, increased during the intervention by an average of 30min per day. Non-exercise activity thermogenesis (NEAT) decreased, on average, by 175kcald(-1) (-22%) from baseline to the intervention and baseline fitness was correlated with change in NEAT.

CONCLUSIONS

Potential alterations in non-exercise activity should be considered when exercise is prescribed. The provision of appropriate education on how to self-monitor daily activity levels may improve intervention outcomes in groups who are new to exercise.

PRACTICE IMPLICATIONS

Strategies to sustain incidental and light physical activity should be offered to help empower individuals as they develop and maintain healthy and long-lasting lifestyle habits.

Does tailoring make a difference? A systematic review of the long-term effectiveness of tailored nutrition education for adults

Tailoring individualizes information to the receiver and provides a potential strategy for improving dietary intakes. The present systematic review summarizes evidence for the long-term (> or =6 months) effectiveness of tailored nutrition education for adults and includes priority population groups. Key electronic databases and relevant bibliographies were searched for trials measuring the following outcomes: nutrition-related health behaviors (e.g., dietary intake and food purchases) and anthropometric measures. Data synthesis was comprised of meta-analysis (for 15 trials including all population groups) and narrative review (for five trials of priority population groups). Overall, the quality of the studies was moderate to good. Tailored nutrition education was found to be a promising strategy for improving the diets of adults (including those in priority population groups) over the long term. However, future studies should ensure adequate reporting of research design and methods and reduce the chances of false-positive findings by using more objective measures of diet, clearly identifying the primary study outcome, and concentrating on outcomes most relevant to nutrition-related disease.

Individual responsiveness to exercise-induced fat loss is associated with change in resting substrate utilization

Fat loss in response to exercise training varies between individuals, even when differences in compliance to the exercise program are accounted for. The purpose of this study was to investigate whether individual variation in change in fasting respiratory quotient (RQ) after exercise training contributes to this interindividual variability. Fifty-five premenopausal women participated in a 7-week endurance-type exercise training program; and fitness, body composition, and resting substrate utilization and metabolic rate in the fasted state were assessed at baseline and postintervention. Total net energy expenditure of the exercise intervention (exEE) was determined from heart rate obtained in all exercise sessions and individualized calibration of the heart rate vs oxygen uptake relationship. Dietary intake and physical activity (by constant heart rate monitoring) were assessed at baseline and during the final week of the intervention. Mean change in fat mass for the group was -0.97 kg (range, +2.1 to -5.3 kg). The strongest correlate of change in fat mass was exEE (r = 0.60, P < .0005). Change in fasting RQ correlated significantly (r = -0.26, P = .05) with the residual for change in fat mass after adjusting for the effects of both exEE and change in energy intake, explaining 7% of the variance. In multiple regression analysis, exEE (P < .0005) and change in fasting RQ (P = .02) were the only statistically significant independent predictors of change in fat mass, together explaining 40.2% of the variance. Thus, fat loss in response to exercise training depends not only on exercise energy expenditure but also on exercise training-induced changes in RQ at rest. This suggests that development of strategies to maximize the change in resting fat oxidation in response to an exercise training program may help individuals to maximize exercise-induced fat loss.

Home-centred physical fitness programme in morbidly obese individuals: a randomized controlled trial

Objective: To assess the effectiveness of domiciliary physical fitness programmes in obese individuals.

Design: Nine-month randomized controlled trial.

Setting: Home-based intervention with outpatient visits.

Subjects: Morbidly obese subjects (body mass index (BMI) ≥30) aged 25—65 years suitable for physical activities at home.

Intervention: At the end of a preliminary one-month in-hospital rehabilitation programme (baseline), 52 patients were randomly assigned either to a structured educational programme (intervention group) of daily incremental physical activity at home (walking and skeletal muscle resistance training, with booklets and written instructions) or to a programme of general advice (control group) regarding exercise and long-term fitness.

Main measures: Both groups were evaluated at baseline and every three months for: (1) time, metabolic equivalents (METs), and heart rate reserve (HRR) during a standardized 2-km walking test (2kmWT); (2) anthropometric measures (body weight, BMI, abdominal and neck circumference); (3) the Polar Fitness Test index (PFTI), and (4) time to exhaustion while sustaining consecutive isoload extensions in the dominant leg (isoload LE). Time during 2kmWT was the study primary outcome.

Results: Body weight, BMI and abdominal circumference improved significantly (P<0.05) over time in the intervention group. The cardiopulmonary fitness variables changed significantly (P<0.05) over time in both study groups. However, all variables improved in the intervention patients, while some worsened or remained stable in the controls. Thus, the mean group difference in changes was significant (P<0.05) for 2kmWT time (—77.4 seconds), HRR (11.7%), and PFTI (5.4 points).

Conclusion: This structured domiciliary fitness programme is feasible and provides sustained anthropometric and physiological benefits in some morbidly obese individuals.

Using heart-rate feedback to increase physical activity in children

OBJECTIVE

The objective of this study was to test whether heart-rate feedback prompts increased physical activity (PA) in primary school students.

METHODS

A controlled trial with 210 9-11 year olds from subsidized Hong Kong Government primary schools was completed in December 2006. Schools were randomly assigned to one of three groups: Control (CG); Educational program (EG); No-educational program (NEG).

INTERVENTION

In a short-term school-based intervention, heart-rate feedback was given either in combination with an educational program (EG) or in isolation (NEG). Long-term retention was assessed in comparison to the control group after 6 months follow-up.

MAIN OUTCOME MEASURES

Physical activity and changes in attraction to PA.

RESULTS

In the short-term, heart-rate monitor feedback increased total daily PA by an average of 24% (p<0.001) and vigorous PA by 0.6% (p<0.05). No change was found for moderate PA. Increases occurred regardless of involvement in the educational program, and in the absence of any change in attitudes towards PA. No long-term retention was apparent.

CONCLUSIONS

The findings from the study suggest that feedback from heart-rate monitors encourages low intensity PA, but when removed increases do not persist.

Variability in adherence to an unsupervised exercise prescription in obese women

OBJECTIVE

To measure adherence to a specific exercise prescription (1500 kcal week(-1)) by objectively quantifying unsupervised exercise energy expenditure (ExEE) in obese women.

DESIGN

The 16-week lifestyle intervention consisted of weekly meetings with research staff and promotion of increased ExEE (1500 kcal week(-1)) and a decreased dietary intake (-500 kcal day(-1)).

PARTICIPANTS

Twenty-nine obese females (body mass index=36.8+/-5.0 kg m(-2), body fat=49.6+/-3.7%) from a hospital-based lifestyle intervention were included in the analysis.

MEASUREMENTS

ExEE was estimated and monitored weekly using heart rate monitoring, and body composition was measured before and after the intervention by dual-energy X-ray absorptiometry.

RESULTS

Free-living adherence to the exercise prescription was variable and, on average, modest such that 14% achieved 1500 kcal week(-1), and the average weekly ExEE (768 kcal week(-1)) represented 51.2% of the total amount prescribed. ExEE was correlated with changes in body weight (r=0.65, P<0.001) and fat mass (r=0.65, P<0.001). Achievement of a 5% weight loss target was dependent on the achievement of an ExEE level of 1000 kcal week(-1) (P<0.001). Exercise 'adherers' (>1000 kcal week(-1)) lost more weight (-9.9 vs -4.1 kg), more fat mass (-6.8 vs -3.0 kg) and more waist circumference (-9.8 vs -5.6 cm) when compared to 'non-adherers' (<1000 kcal week(-1)).

DISCUSSION

Exercise is an integral component of lifestyle interventions aimed at reducing obesity and its complications. However, without accurate and objective measures of ExEE, it is difficult for relationships between exercise and health outcomes to be elucidated. The present study suggests an alternative to self-report to increase the confidence with which conclusions are drawn regarding the role of exercise within lifestyle interventions.

Individual variability following 12 weeks of supervised exercise: identification and characterization of compensation for exercise-induced weight loss

OBJECTIVE

To identify and characterize the individual variability in compensation for exercise-induced changes in energy expenditure (EE).

DESIGN

Twelve-week exercise intervention.

SUBJECTS

Thirty-five overweight and obese sedentary men and women (body mass index, 31.8+/-4.1 kg m(-2); age, 39.6+/-11.0 years) were prescribed exercise five times per week for 12 weeks under supervised conditions.

MEASUREMENTS

Body weight, body composition, resting metabolic rate (RMR), total daily energy intake (EI) and subjective appetite sensations were measured at weeks 0 and 12.

RESULTS

When all subjects' data were pooled, the mean reduction in body weight (3.7+/-3.6 kg) was significant (P<0.0001) and as predicted, which suggested no compensation for the increase in EE. However, further examination revealed a large individual variability in weight change (-14.7 to +1.7 kg). Subjects were identified as compensators (C) or noncompensators (NC) based on their actual weight loss (mean NC=6.3+/-3.2 kg and C=1.5+/- 2.5 kg) relative to their predicted weight loss. C and NC were characterized by their different metabolic and behavioural compensatory responses. Moderate changes in RMR occurred in C (-69.2+/-268.7 kcal day(-1)) and NC (14.2+/-242.7 kcal day(-1)). EI and average daily subjective hunger increased by 268.2+/-455.4 kcal day(-1) and 6.9+/-11.4 mm day(-1) in C, whereas EI decreased by 130+/-485 kcal day(-1) and there was no change in subjective appetite (0.4+/-9.6 mm day(-1)) in NC.

CONCLUSION

These results demonstrate that expressing the exercise-induced change in body weight as a group mean conceals the large inter-individual variability in body weight and compensatory responses. Individuals who experience a lower than predicted weight loss are compensating for the increase in EE.