Weight Loss and the Prevention of Weight Regain: Evaluation of a Treatment Model of Exercise Self-Regulation Generalizing to Controlled Eating

Temporal Aspects of Psychosocial Mediators of the Exercise-Weight Loss Maintenance Relationship Within Scalable Behavior-Change Treatments

STUDY BACKGROUND

Limited knowledge of psychological correlates of weight loss is associated with continuing failures of behavioral obesity treatments beyond the short term.

PURPOSE

This study aimed to inform health professionals' obesity interventions via an increased knowledge of mediators of the exercise-weight loss maintenance relationship.

METHODS

Women participated in 6-month obesity treatments within community settings emphasizing moderate exercise and self-regulation skills development via primarily in-person (n = 54) or primarily written (n = 54) means. Changes in mood, self-regulating eating, and weight over 6, 12, and 24 months were assessed. A moderated mediation model was tested using the PROCESS macro instruction.

RESULTS

Improvements in mood, self-regulating eating, and weight were significantly greater in the in-person group. The relationship between a dichotomous measure of completing at least 3 sessions of exercise per week (or not) and change in weight over 6 months was no longer significant when the mediators of changes in negative mood and self-regulation of eating were sequentially entered. Paths of exercise→negative mood reduction→eating self-regulation increase→weight loss over 6, 12 and 24 months were significant. Exercise self-regulation at Month 3 significantly moderated the mood change→eating self-regulation change relationship.

CONCLUSIONS

Based on the identified paths, scalable obesity-treatment content and emphases were informed. This could help guide health professionals' actions concerning the management of obesity.

Obesity treatment-associated transfer of exercise-related self-regulation to eating-related self-regulation changes in women

Obesity in the United States has risen to 42 percent of its adult population and is similarly problematic in many other countries. Although the U.S. government has provided education on healthy eating and the need to exercise regularly, behavioral obesity treatments have largely failed to sustain reductions in weight. Self-regulation, and the incorporation of exercise for its psychological impacts on eating, has sometimes been targeted. While there has been sporadic investigation into the carry-over of exercise-related self-regulation to eating-related self-regulation, the present aim is to further inquiry in that area to inform future treatment content for improved effects. Women enrolled in community-based obesity treatments with either a self-regulation (n = 106) or education (n = 54) focus were assessed on changes in exercise- and eating-related self-regulation, negative mood, completed exercise, and weight. Improvements were significantly greater in the self-regulation-focused group. After controlling for initial change in eating-related self-regulation, change in that measure from Month 3 to 6 was significantly predicted by change in exercise-related self-regulation during the initial 3 treatment months. This suggested a carry-over effect. A stronger predictive relationship was associated with the self-regulation-focused treatment. In further analyses, paths from changes in exercise→negative mood→self-regulation of both exercise and eating were significant. Increase in eating-related self-regulation was significantly associated with weight loss over 6, 12, and 24 months. The self-regulation-focused group had stronger relationships, again. Findings suggested utility in targeting exercise-related self-regulation to impact later change in eating-related self-regulation, and the use of exercise-associated mood improvement to bolster participants' self-regulation capabilities.

Behavioral and Psychosocial Mediators of the Effects of Increased Self-Regulation on Short- and Long-Term Weight Loss in Women Within Community-Based Obesity Treatments

The aim of this study was to evaluate behavioral mediators of relationships between increased self-regulation of eating and weight loss so that findings on psychosocial correlates of treatment-associated weight change could be extended. Participants were women enrolled in 6-month community-based obesity treatments using primarily self-regulatory (SR-treatment, n = 52) or education-focused (Didactic training, n = 54) methods. Changes from baseline in self-regulation of eating, self-efficacy for controlled eating, emotional eating propensity, exercise, and the diet were first calculated. There were significant overall improvements in each psychosocial and behavioral measure, and weight. Except for emotional eating change from baseline-Month 12, improvements were each significantly greater in the SR-treatment group. Mediation of the relationships of change in self-regulation with 6-, 12-, and 24-month weight changes, by changes in self-efficacy and emotional eating, were significant, R2s = .19-.26, ps < .001. Only changes in emotional eating over 6 and 12 months were significant mediators. Mediations of the same self-regulation-weight change relationships by changes in exercise and the diet were also significant, R2s = .19-.28, ps < .001, and only changes in exercise over 12 and 24 months were significant mediators. Although group membership did not moderate effects on weight, substitution of sweets for the (composite) diet demonstrated it to be a significant mediator over 6 and 12 months. In women with obesity, self-regulation improvement was associated with short- and longer-term weight loss through changes in emotional eating, exercise, and sweets consumption. Thus, behavioral treatments will benefit from targeting those variables.

Health and Wellness Coaching and Sustained Gains: A Rapid Systematic Review

The Transtheoretical Model of Change identifies key stages in behavior change, including a maintenance stage occurring when a behavior has been upheld for at least 6 months. Health and wellness coaching has demonstrated support for health behavior change, but maintenance of gains has received little attention. Our rapid systematic literature review characterizes both the research exploring sustained gains with health and wellness coaching and what is known about sustained gains after the completion of a health and wellness coaching engagement. Guided by The Cochrane Rapid Reviews Methods Group "Interim Guidance," we drew 231 studies from the 2018 and 2020 Sforzo et al "Compendium of the health and wellness coaching literature," and "Addendum…" appendices. Initial screening and coding for inclusion and exclusion criteria yielded 28 studies for data extraction. We examined studies across outcome categories (physiological, behavioral, psychological, and health risk assessment) to determine whether outcome measures were: not sustained; partially sustained; fully sustained; or improved from immediate post-intervention to a later follow-up period. Twenty-five of the 28 studies reviewed demonstrated partially, or fully, sustained or improved outcomes in one or more variables studied, with sustained gains demonstrated across outcome categories, strengthening confidence in HWC as a facilitator of lasting change.

A Rubric to Assess the Design and Intervention Quality of Randomized Controlled Trials in Health and Wellness Coaching

Objective

To collect health and wellness coaching (HWC) literature related to treatment of obesity and Type 2 Diabetes (T2D) for systematic assessment using a novel rubric.

Data Source

Pubmed, CINAHL, and PsychInfo.

Study Inclusion and Exclusion

Given 282 articles retrieved, only randomized and controlled trials meeting a HWC criteria-based definition were included; studies with intervention <4 months or <4 sessions were excluded.

Data Extraction

Rubric assessment required details of two theoretical frameworks (i.e., study design and HWC intervention design) be extracted from each included paper.

Data Synthesis

Data were derived from a 28-item rubric querying items such as sampling characteristics, statistical methods, coach characteristics, HWC strategy, and intervention fidelity.

Results

29 articles were reviewed. Inter-rater rubric scoring yielded high intraclass correlation (r = .85). Rubric assessment of HWC literature resulted in moderate scores (56.7%), with study design scoring higher than intervention design; within intervention design, T2D studies scored higher than obesity.

Conclusions

A novel research design rubric is presented and successfully applied to assess HWC research related to treatment of obesity and T2D. Most studies reported beneficial clinical findings; however, rubric results revealed moderate scores for study and intervention design. Implications for future HWC research are discussed.

Engineering Virtuous health habits using Emotion and Neurocognition: Flexibility for Lifestyle Optimization and Weight management (EVEN FLOW)

Interventions to preserve functional independence in older adults are critically needed to optimize 'successful aging' among the large and increasing population of older adults in the United States. For most aging adults, the management of chronic diseases is the most common and impactful risk factor for loss of functional independence. Chronic disease management inherently involves the learning and adaptation of new behaviors, such as adopting or modifying physical activity habits and managing weight. Despite the importance of chronic disease management in older adults, vanishingly few individuals optimally manage their health behavior in the service of chronic disease stabilization to preserve functional independence. Contemporary conceptual models of chronic disease management and health habit theory suggest that this lack of optimal management may result from an underappreciated distinction within the health behavior literature: the behavioral domains critical for initiation of new behaviors (Initiation Phase) are largely distinct from those that facilitate their maintenance (Maintenance Phase). Psychological factors, particularly experiential acceptance and trait levels of openness are critical to engagement with new health behaviors, willingness to make difficult lifestyle changes, and the ability to tolerate aversive affective responses in the process. Cognitive factors, particularly executive function, are critical to learning new skills, using them effectively across different areas of life and contextual demands, and updating of skills to facilitate behavioral maintenance. Emerging data therefore suggests that individuals with greater executive function are better able to sustain behavior changes, which in turn protects against cognitive decline. In addition, social and structural supports of behavior change serve a critical buffering role across phases of behavior change. The present review attempts to address these gaps by proposing a novel biobehavioral intervention framework that incorporates both individual-level and social support system-level variables for the purpose of treatment tailoring. Our intervention framework triangulates on the central importance of self-regulatory functioning, proposing that both cognitive and psychological mechanisms ultimately influence an individuals' ability to engage in different aspects of self-management (individual level) in the service of maintaining independence. Importantly, the proposed linkages of cognitive and affective functioning align with emerging individual difference frameworks, suggesting that lower levels of cognitive and/or psychological flexibility represent an intermediate phenotype of risk. Individuals exhibiting self-regulatory lapses either due to the inability to regulate their emotional responses or due to the presence of executive functioning impairments are therefore the most likely to require assistance to preserve functional independence. In addition, these vulnerabilities will be more easily observable for individuals requiring greater complexity of self-management behavioral demands (e.g. complexity of medication regimen) and/or with lesser social support. Our proposed framework also intuits several distinct intervention pathways based on the profile of self-regulatory behaviors: we propose that individuals with intact affect regulation and impaired executive function will preferentially respond to 'top-down' training approaches (e.g., strategy and process work). Individuals with intact executive function and impaired affect regulation will respond to 'bottom-up' approaches (e.g., graded exposure). And individuals with impairments in both may require treatments targeting caregiving or structural supports, particularly in the context of elevated behavioral demands.

Long-term effects on weight loss and maintenance by intensive start with diet and exercise

This 36-month study aimed to determine whether exercise intervention added to weight loss treatment in the beginning or at 6 months is effective for weight loss and long-term weight maintenance. A total of 120 obese adults (body mass index >30) were randomly assigned to intensified behavioral modification (iBM), iBM+ additional exercise from 0 to 3 months (CWT1), iBM+ additional exercise from 6 to 9 months (CWT2), and a control group (CON). Questionnaires and measurements were collected at baseline, 3, 9, 24, and 36 months. The intervention consisted of an 12 months intensified weight-loss period followed by a 24 months weight-maintenance period. Eighty (67%) subjects (mean age 46.0 years, BMI 36.2) completed the trial. Compared with the control group, all three intervention groups had significant weight loss during the 36-month intervention period (p < 0.001). The achieved weight loss remained significant at 36 months in the iBM (-6.8%, p < 0.001), the CWT1 (-5.8%, p < 0.001), and the CWT2 group (-3.9%, p < 0.001). The CWT1 group showed significant reduction in waist circumference at 9 months (-11.3 cm, p < 0.001), at 24 months (-8.8 cm, p < 0.001), and at 36 months (-8.7 cm, p < 0.001). Intensified behavioral modification alone and with exercise resulted in clinically significant weight loss and long-term weight maintenance. The addition of exercise at the onset promoted greater reductions in waist circumference. In the treatment of obesity, including severe obesity, more intensive lifestyle interventions with exercise should be incorporated.

Morning individuals in Saudi Arabia have higher self-regulation of eating behavior compared to evening types

Chronotype is a manifestation of an individual's circadian system, which can be presented as a preference for morningness or eveningness. Evening chronotype has been linked to unhealthy dietary habits. These habits are partially from poor self-regulation of eating behavior (SREB). SREB is a goal-directed process that helps resist food temptation and achieve desired dietary outcomes. It is unclear whether chronotype is associated with SREB. This study aims to investigate the association between chronotypes and SREB. A total of 599 adults (18-50 years) enrolled in this cross-sectional study. Participants received an online questionnaire that collected sociodemographic, anthropometrics, chronotype through the validated reduced Morningness-Eveningness Questionnaire (rMEQ) and SREB using the SREB Questionnaire. ANOVA, Chi-square and multivariate logistic regression were used. In adjusted models, morning types had 85% higher SREB compared to evening types (p = 0.003, OR = 1.85). Evening types found fried foods (p = 0.003), chips (p = 0.005) and French fries (p = 0.018) more tempting than morning types. These findings show a link between chronotype and SREB. Strategies focusing on SREB may help evening types improve dietary habits. Further studies are required to clarify the underlying mechanisms for these associations. This may have important implications for lifestyle and behavioral change policy.

Coaction of Obesity Treatment-Associated Changes in Physical Activity and Emotional Eating: Mediation by Body Satisfaction

BACKGROUND

Research on coaction suggests improvements in physical activity and emotional eating will occur in a reciprocal manner.

AIMS

To determine if changes in body satisfaction mediate relations between physical activity and emotional eating changes and if age affects degree of change in those variables.

METHOD

Groups of early adult (n = 43) and middle-age (n = 52) women participants of a community-based obesity treatment were assessed on behavioral and psychological variables over 3 and 6 months.

RESULTS

Improvements in physical activity, anxiety-related emotional eating, body satisfaction, anxiety, and exercise self-efficacy were significant overall. Early adults demonstrated greater reductions in emotional eating. Physical activity increase over 3 months significantly predicted 6-month reduction in emotional eating but not vice versa. Body satisfaction change significantly mediated the physical activity-emotional eating relationships. Changes in anxiety and exercise self-efficacy moderated activity → emotional eating and body satisfaction → physical activity relationships, respectively.

CONCLUSION

Findings can inform both theory and behavioral obesity interventions.

Sequential Changes Advancing from Exercise-Induced Psychological Improvements to Controlled Eating and Sustained Weight Loss: A Treatment-Focused Causal Chain Model

INTRODUCTION

Behavioral (nonsurgical/nonpharmacologic) weight loss treatments have been overwhelmingly unsuccessful beyond the short term. Rather than incorporating accepted behavioral change theory, most have inadequately relied on providing exercise and nutrition information. Although adherence is a challenge, exercise has emerged as the most robust predictor of sustained weight reduction. However, exercise might be more associated with long-term weight loss through the relationship of its associated psychological changes with improved nutrition than through direct effects of energy expenditures, which are typically minimal in deconditioned individuals.

OBJECTIVE

To facilitate improved helping methods through a proposed theory-based causal chain model in which supported exercise predicts sustained weight loss through successive changes in exercise-related, then eating-related, self-regulation, self-efficacy, and mood.

RESULTS

Segments of the model predict that 1) exercise and eating behaviors will be sequentially improved through increased self-regulatory skill use and self-efficacy and 2) exercise-induced mood improvements will foster greater self-regulation and reduced emotional eating. Short-term psychosocial changes can be leveraged to carry over to longer-term changes and maintained weight reductions. Suggested interventions emerging from the model and supporting research include using self-regulation to enable a habit of regular moderate exercise, facilitating a transfer of self-regulatory skills from an exercise to eating context, and leveraging mood improvements associated with manageable volumes of exercise to improve eating behaviors.

CONCLUSION

The model presents an evidence-based explanation of the exercise-weight loss association through psychosocial mechanisms. It also informs the development of practical methods to facilitate sustainable reductions in weight and health risks in adults with obesity.

Adipocyte abundances of CES1, CRYAB, ENO1 and GANAB are modified in-vitro by glucose restriction and are associated with cellular remodelling during weight regain

Long-term weight loss maintenance is a problem of overweight and obesity. Changes of gene expression during weight loss (WL) by calorie restriction (CR) are linked to the risk of weight regain (WR). However, detailed information on genes/proteins involved in the mechanism is still lacking. Therefore, we developed an in-vitro model system for glucose restriction (GR) and refeeding (RF) to uncover proteome differences between GR with RF vs normal feeding, of which we explored the relation with WR after WL. Human Simpson-Golabi-Behmel Syndrome cells were subjected to changing levels of glucose to mimic the condition of CR and RF. Proteome profiling was performed by liquid chromatography tandem mass spectrometry. This in-vitro model revealed 44 proteins differentially expressed after GR and RF versus feeding including proteins of the focal adhesions. Four proteins showed a persistent up- or down-regulation: liver carboxylesterase (CES1), mitochondrial superoxide dismutase [Mn] (SOD2), alpha-crystallin B-chain (CRYAB), alpha-enolase (ENO1). In-vivo weight loss-induced RNA expression changes linked CES1, CRYAB and ENO1 to WR. Moreover, of these 44 proteins, CES1 and glucosidase II alpha subunit (GANAB) during follow up correlated with WR. Correlation clustering of in-vivo protein expression data indicated an interaction of these proteins with structural components of the focal adhesions and cytoplasmic filaments in the adipocytes.

Relations of change in fruit and vegetable intake with overall energy reduction and physical activity with weight change: Assessing theory-based psychosocial mediators

BACKGROUND

Increased physical activity and fruit and vegetable (FV) intake are typically suggested to counter obesity. Sustained behavior change in those areas has, however, been poor, possibly because of a lack of understanding of the effects of psychosocial factors. Using data from previous research, this study aimed to better define the role of physical activity and FV intake in short- and long-term weight loss via changes in malleable psychosocial mediators and moderators.

METHODS

Women who were obese (n = 183; age = 50.0 ± 7.9 years; body mass index = 35.2 ± 3.2 kg/m², mean ± SD) and who previously participated in 3 different community-based behavioral weight-loss treatments were assessed over 2 years. Changes in FV intake, physical activity, self-regulation of physical activity and eating (aggregated), negative mood, and weight were measured over 6 and 24 months.

RESULTS

Changes in each variable over both 6 and 24 months were significant (all p values <0.001). The FV intake to the weight-related caloric intake relationship (β = -0.30, p < 0.001) was significantly mediated by self-regulation change over 6 months. The physical activity to weight-change relationship (β = -0.46, p < 0.001) was significantly mediated by both self-regulation and mood change over 24 months. Physical activity, itself, accounted for only 16% of weight-related caloric expenditure differences. Changes in physical activity and FV intake were each independent predictors of weight change over 24 months (overall R ² = 0.50, p < 0.001).

CONCLUSION

Findings clarified theory-based targets for weight-management treatments and suggested that future weight-loss treatments strongly focus on developing self-regulatory skills to address barriers to behavioral changes.

Determinants of weight loss maintenance: a systematic review

BACKGROUND

Discerning the determinants of weight loss maintenance is important in the planning of future interventions and policies regarding overweight and obesity. We have therefore systematically synthesized recent literature on determinants of weight loss maintenance for individuals with overweight and obesity.

METHODS

With the use of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement, prospective studies were identified from searches in PubMed and PsycINFO from 2006 to 2016. We included articles investigating adults with overweight and obesity undergoing weight loss without surgery or medication. Included articles were scored on their methodological quality, and a best-evidence synthesis was applied to summarize the results.

RESULTS

Our search resulted in 8,222 articles of which 67 articles were selected. In total, 124 determinants were identified of which 5 were demographic, 59 were behavioural, 51 were psychological/cognitive and 9 were social and physical environmental determinants. We found consistent evidence that demographic determinants were not predictive of weight loss maintenance. Behavioural and cognitive determinants that promote a reduction in energy intake, an increase in energy expenditure and monitoring of this balance are predictive determinants.

CONCLUSION

This review identifies key determinants in weight loss maintenance. However, more research regarding cognitive and environmental determinants of weight loss maintenance is needed to advance our knowledge on determinants of weight loss maintenance.

Are physical activity interventions for healthy inactive adults effective in promoting behavior change and maintenance, and which behavior change techniques are effective? A systematic review and meta-analysis

Physical inactivity and sedentary behavior relate to poor health outcomes independently. Healthy inactive adults are a key target population for prevention. This systematic review and meta-analysis aimed to evaluate the effectiveness of physical activity and/or sedentary behavior interventions, measured postintervention (behavior change) and at follow-up (behavior change maintenance), to identify behavior change techniques (BCT) within, and report on fidelity. Included studies were randomized controlled trials, targeting healthy inactive adults, aiming to change physical activity and/or sedentary behavior, with a minimum postintervention follow-up of 6 months, using 16 databases from 1990. Two reviewers independently coded risk of bias, the "Template for Intervention Description and Replication" (TIDieR) checklist, and BCTs. Twenty-six studies were included; 16 pooled for meta-analysis. Physical activity interventions were effective at changing behavior (d = 0.32, 95% confidence intervals = 0.16-0.48, n = 2,346) and maintaining behavior change after 6 months or more (d = 0.21, 95% confidence intervals = 0.12-0.30, n = 2,190). Sedentary behavior interventions (n = 2) were not effective. At postintervention, physical activity intervention effectiveness was associated with the BCTs "Biofeedback," "Demonstration of the behavior," "Behavior practice/rehearsal," and "Graded tasks." At follow-up, effectiveness was associated with using "Action planning," "Instruction on how to perform the behavior," "Prompts/cues," "Behavior practice/rehearsal," "Graded tasks," and "Self-reward." Fidelity was only documented in one study. Good evidence was found for behavior change maintenance effects in healthy inactive adults, and underlying BCTs. This review provides translational evidence to improve research, intervention design, and service delivery in physical activity interventions, while highlighting the lack of fidelity measurement.

Starting university with high eating self-regulatory skills protects students against unhealthy dietary intake and substantial weight gain over 6 months

BACKGROUND

There is consistent evidence that suggests first year students are at risk of weight gain, but the reasons for this vulnerability are still unclear. This study aimed to explore whether the ability to regulate eating behaviours is a predictor of weight and dietary changes in first year undergraduate students.

METHODS

First year undergraduate students from universities situated in London were invited to complete a survey at the beginning of the academic year and at 6-month follow-up. Each survey included the Self-Regulation of Eating Behaviour Questionnaire, food frequency questions, socio-demographic questions and anthropometric questions. Linear and logistic regressions were performed to explore the associations between baseline eating self-regulatory skills and weight and dietary changes.

RESULTS

481 first year undergraduate students took part in the study. Students who entered university with higher eating self-regulatory skills were more likely to maintain or achieve a higher fruit and vegetable (OR = 1.8, p = 0.007) and a lower sweet and salty snack (OR = 1.9, p = 0.001) intake over the course of the first 6 months in university. Higher baseline eating self-regulatory skills were also related to lower weight changes (β = -0.15, p = 0.018) and lower likelihood of gaining 5% initial body weight (OR = 0.52, p = 0.006) at 6-month. Additionally, self-regulatory skills moderated the relationship between baseline BMI and weight changes (β = -0.25, p ≤0.001) and between baseline BMI and 5% weight gain (OR = 0.82, p = 0.008).

CONCLUSIONS

Starting university with higher eating self-regulatory skills may help students to maintain or achieve a healthy diet and protect them against substantial weight gain, especially among students with overweight.

Exercise effects on mood, and its associations with self-regulatory skills, self-efficacy, and eating changes during the year following weight-loss treatment

Maintaining weight loss beyond an initial year of behavioral treatment is of concern, and understanding interrelationships of theory-based psychosocial correlates is minimal. Although exercise is universally suggested, its indirect impacts on long-term nutritional changes are unclear. Data from women with obesity (N= 129), who participated in the treatment groups of two initial trials of a new social cognitive theory-based weight-loss protocol during 2016-2017, were incorporated. The intervention emphasized exercise adherence for two months prior to the next 12 months of biweekly meetings for nutritional change. Effects of exercise-induced changes in mood, and the role of self-regulatory skills in facilitating self-efficacy and improved eating 12-24 months after treatment initiation, were assessed. Change in mood significantly moderated changes in self-regulation for controlled eating by exercise-related self-regulation. During Months 12 to 24, changes in both fruit/vegetable and sweets intake, by self-regulation for eating change, was significantly mediated by change in self-efficacy for controlled eating. Mood change from Months 12 to 24 was significantly associated with change in exercise, with indications that maintaining an equivalent of three days/week had critical value. Findings suggest the importance of bolstering self-regulatory skill usage beyond an initial year of treatment in women.

Health and Wellness Coaching Improves Weight and Nutrition Behaviors

Most Americans have an eating pattern inconsistent with the Dietary Guidelines, putting them at risk for obesity and chronic disease. Health and wellness coaching (HWC) for lifestyle behavior change is emerging as a potentially effective tool to prevent and treat chronic disease. A systematic literature review identified 11 randomized controlled trials studying the use of HWC for improving nutrition-related biomarkers and eating behaviors. These trials demonstrate efficacy of HWC across diverse populations and treatment modalities. Almost all (82%) of the trials showed an improvement in at least one outcome. The most commonly studied outcomes were weight, blood pressure, and fruit, vegetable, and fat intake. There are several gaps in the research. The assessment of nutrition-related behaviors can be expanded to include assessment of diet quality and eating patterns associated with chronic disease prevention. Research is needed to evaluate HWC for nutrition-related biomarkers and behaviors in understudied populations with known health disparities. In addition, the health coaching dosage for long-term maintenance of changed outcomes and behaviors is inconsistent or unknown. These gaps will be important to address to determine policies and best practices for future application of HWC.

Exercise Predicts Long-Term Weight Loss in Women With Class 1 and Class 2 Obesity Through Effects on Emotional Eating and its Correlates

Background: The relationship between exercise and long-term weight loss is definitive. However, in deconditioned individuals, the basis of that relationship beyond minimal energy expenditures is unclear. Effects emanating from exercise’s proposed association with changes in emotional eating and its psychosocial correlates were tested. Methods: Women with class 1 (n = 67) and class 2 (n = 53) obesity, participating in a new community-based weight-loss treatment based on tenets of social cognitive theory, were assessed at baseline and Months 3, 6, 12, and 24 on weight and measures of exercise outputs, emotional eating, eating self-regulation, and negative mood. An exercise-support component was provided for 2 months prior to group nutrition-change sessions. Results: Improvements from baseline were significant on all measures but did not significantly differ by group. Although not for the initial 3 months, changes in exercise significantly predicted weight changes over 6, 12, and 24 months from baseline. However, only 26%–31% of the lost weight was directly attributable to exercise-related energy expenditures. Changes in emotional eating significantly mediated the exercise–weight-loss relationship, and changes in self-regulation and mood significantly mediated the exercise–emotional eating relationship. Conclusions: Findings supported exercise’s role in long-term weight loss primarily through psychosocial factors.

Exercise Program-Related Psychosocial Changes Promote Healthy Weight in Youth

Background:

An inappropriately high weight in children is a predictor of health risks. Reliable interventions that are easily disseminated are needed.

Objective:

Based on findings with adults, exercise-support methods might be leveraged to change behavioral predictors of a healthy body composition in youth. Analyses of changes in theory-based psychological variables’ association with changes in body composition within the context of youth-tailored treatment are required.

Method:

A 45 minute/day, 4 day/week, social cognitive/self-efficacy theory-based after-school care protocol, Youth Fit 4 Life, was tested in children of a normal (n=54) and overweight/obese (n=32) body composition over a school year. The treatment’s emphasis was on improvements in mood, self-efficacy, and self-regulation related to physical activity. Validated self-report measures of negative mood, self-regulation, and self-efficacy, and BMI, were administered at baseline, and months 3 and 9. The prediction of BMI change from changes in the psychosocial variables was assessed using multiple regression analyses.

Results:

Change in BMI and improvements in the aforementioned psychosocial factors were significant over both 3 and 9 months, and did not differ between body composition groups. Analyses indicated that over 3 months, self-regulation change was a significant predictor of BMI change (β=-0.26, SE=0.05, P=0.03), while over 9 months, self-efficacy change significantly predicted BMI change (β=-0.21, SE=0.02, P=0.05).

Conclusion:

After replications and extensions focused also on eating behaviors, it was suggested that the inexpensive and efficient Youth Fit 4 Life protocol might be scalable across community venues to address childhood overweight and obesity.

Directionality in the Relationship of Self-regulation, Self-efficacy, and Mood Changes in Facilitating Improved Physical Activity and Nutrition Behaviors: Extending Behavioral Theory to Improve Weight-Loss Treatment Effects

OBJECTIVE

To improve understanding of directionality in the dynamic relationships among psychosocial predictors of behavioral changes associated with weight loss.

METHODS

In women with obesity participating in a new behavioral weight-loss treatment that emphasizes physical activity (n = 53; body mass index = 34.7 ± 3.3 kg/m²), mediation and moderated-mediation models were fit to assess directionality in the self-efficacy-self-regulation change relationship and additional effects of mood change and its basis on fruit/vegetable intake and physical activity behaviors through month 6 and from months 6 to 24.

RESULTS

Self-regulation was a stronger predictor of change in self-efficacy than vice versa. Mood change did not moderate the relationships significantly between changes in self-efficacy and/or self-regulation, and weight loss behavior. Emotional eating significantly changed mediated relationships between changes in mood and fruit/vegetable intake through month 6 (95% confidence interval, -0.05 to 0.00).

CONCLUSIONS AND IMPLICATIONS

Findings clarified relationships of self-efficacy, self-regulation, and mood in the prediction of weight loss behaviors, and informed behavioral treatments for improved outcomes.

Effects of the Youth Fit 4 Life physical activity/nutrition protocol on body mass index, fitness and targeted social cognitive theory variables in 9- to 12-year-olds during after-school care

AIM

Childhood overweight and obesity is unacceptably high in industrialised nations. School-based interventions have largely been atheoretical and ineffective. This study aimed to test a new theory-based protocol for its effects on measures of fitness and body mass index (BMI), and its proposed psychosocial mediators, during elementary after-school (out-of-school hours) care.

METHODS

Nine- to 12-year-old participants of YMCA-based after-school care in the southeastern Unites States were randomised into either the experimental Youth Fit 4 Life (YF4L) treatment group (n = 86) or a typical care group (n = 55) for 45 min/day. YF4L is based on social cognitive theory, emphasising mastery over physical activities and the development of self-management/self-regulatory skills to support healthy behaviours. Physiological and psychosocial variables were assessed over a 9-month elementary school year.

RESULTS

Of the overall sample, 28% were overweight or obese at baseline. YF4L was associated with significantly greater improvements in BMI, and measures of self-regulation, mood, self-efficacy, cardiovascular endurance and strength over both 3 and 9 months. Changes in self-regulation, mood and self-efficacy significantly mediated the treatment type-BMI relationship over both 3 months (R ² = 0.12, P = 0.002) and 9 months (R ² = 0.13, P = 0.001), with change in self-regulation being a significant independent mediator. Changes in BMI and self-regulation reciprocally reinforced one another. Gender was not a significant moderator of those relationships.

CONCLUSIONS

The YF4L treatment mitigated rise in BMI in 9- to 12-year-old enrollees of after-school care. The treatment's basis in social cognitive theory was supported. Because of its positive effects and ability to utilise existing staff, large-scale application is warranted after sufficient replication.

Psychosocial changes as correlates of weight regain vs. continued loss within 2-year trials of a self-regulation-focused community-based intervention

Although health-enhancing weight reductions are associated with behavioural treatments initially, a trajectory towards full regain typically begins within 6-9 months. Women with obesity (body mass index = 30-40 kg m^-2 ) who lost at least 3% of their baseline weight within two trials of a new cognitive-behavioural treatment incorporating physical activity prior to changes in eating behaviours, and either regained ≥50% of that weight over 2 years (Regain group, n=32) or continued to lose weight (ContinuedLoss group, n = 34), were assessed from months 6 to 24 on changes in weight-loss behaviours and psychosocial predictors of those behaviours derived from established behavioural theories. For the Regain group, significant decreases in physical activity and fruit/vegetable intake during months 12-24, from both months 6 to 24 and 12 to 24 in eating- and physical activity-related self-regulation and from months 6 to 24 in eating-related self-efficacy (i.e. feelings of ability), were found. No significant behavioural or psychosocial changes were found over those times in the ContinuedLoss group. Changes in self-regulation and self-efficacy completely mediated the relationship between changes in fruit/vegetable intake and group (Regain vs. ContinuedLoss) (McFadden's R ²  = 0.19 and 0.20, respectively), with self-regulation independently contributing to the explained variance. Changes over both months 6-24 and 12-24 in self-regulation significantly mediated the relationship between changes in physical activity and group membership (McFadden's R ²  = 0.24 and 0.27, respectively). Findings suggested that approximately 6 months after treatment initiation would be a suitable time to intervene with some bolstering methods, while approximately 12 months post-initiation would be most applicable for others.

A P-value model for theoretical power analysis and its applications in multiple testing procedures

Background

Power analysis is a critical aspect of the design of experiments to detect an effect of a given size. When multiple hypotheses are tested simultaneously, multiplicity adjustments to p-values should be taken into account in power analysis. There are a limited number of studies on power analysis in multiple testing procedures. For some methods, the theoretical analysis is difficult and extensive numerical simulations are often needed, while other methods oversimplify the information under the alternative hypothesis. To this end, this paper aims to develop a new statistical model for power analysis in multiple testing procedures.

Methods

We propose a step-function-based p-value model under the alternative hypothesis, which is simple enough to perform power analysis without simulations, but not too simple to lose the information from the alternative hypothesis. The first step is to transform distributions of different test statistics (e.g., t, chi-square or F) to distributions of corresponding p-values. We then use a step function to approximate each of the p-value’s distributions by matching the mean and variance. Lastly, the step-function-based p-value model can be used for theoretical power analysis.

Results

The proposed model is applied to problems in multiple testing procedures. We first show how the most powerful critical constants can be chosen using the step-function-based p-value model. Our model is then applied to the field of multiple testing procedures to explain the assumption of monotonicity of the critical constants. Lastly, we apply our model to a behavioral weight loss and maintenance study to select the optimal critical constants.

Conclusions

The proposed model is easy to implement and preserves the information from the alternative hypothesis.

Psychosocial predictors of decay in healthy eating and physical activity improvements in obese women regaining lost weight: translation of behavioral theory into treatment suggestions

Regain of lost weight is a universal problem for behavioral treatments. An increased understanding of theory-based psychosocial predictors of decay in behavioral correlates of weight loss might improve treatments. Data were derived from a previous weight loss investigation of 110 women with obesity. A subsample from the experimental treatment who lost ≥3 % body weight and regained at least one third of that over 24 months (N = 36) was assessed. During months 6 through 24, there were unfavorable changes in behavioral (fruit/vegetable and sweet intake; physical activity) and psychosocial variables. Mood change predicted change in fruit/vegetable and sweet intake, with emotional eating change mediating the latter relationship. Change in self-regulation predicted changes in sweet and fruit/vegetable intake and physical activity, with self-efficacy mediating the self-regulation-fruit/vegetable intake and self-regulation-physical activity relationships. Findings suggest that after treatment-induced weight loss, addressing indicated theory-based psychosocial variables might mitigate decay in behavioral predictors of healthier weight.