Theory-based psychosocial factors that discriminate between weight-loss success and failure over 6 months in women with morbid obesity receiving behavioral treatments

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.

Evaluation of a new causal chain model for predicting embedded psychosocial and behavioral relationships in a community-based obesity treatment seeking maintained weight loss

A new causal chain model positing theory- and research-based interrelationships among psychosocial and behavioral variables leading to weight loss and its maintenance was assessed. Two samples of women participating in community-based cognitive-behavioral obesity treatments were assessed over either 6 months (weight loss phase; N = 103), or additionally including Months 6-12 (weight-loss maintenance phase; N = 101). Analyses first evaluated whether baseline physical, demographic, behavioral (physical activity, fruit/vegetable intake), and/or psychosocial (self-regulation, self-efficacy, negative mood) variables significantly predicted weight change. Further analyses assessed whether changes in model-based behavioral and psychosocial variables significantly differed by groupings of participants based on their short-term weight loss and weight-loss maintenance/further loss. The predictive value of changes in the psychosocial variables on behavioral changes was next assessed, also accounting for group. Finally, mediation, moderation, and moderated mediation analyses tested proposed causal chain-based interrelationships among variables. Of the 12 variables assessed at baseline, only weight was inversely associated with lost weight, and only fruit/vegetable intake was positively associated with effects during the weight-loss maintenance phase. Overall improvements in behavioral and psychosocial variables were significantly greater in participant groupings with better weight loss and weight-loss maintenance results. Changes in self-regulation, self-efficacy, and mood significantly predicted the weight-loss behavior changes, unaffected by group. Results from the five mediation, moderation, and moderated mediation analyses supported hypotheses based on the new causal chain model. The field testing indicated adequacy of the new causal chain model and informed architectures of behavioral obesity treatments concerned with long-term reductions in excess weight.

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.

Generalizability of an adult-validated model for predicting increased physical activity in after-school program children: Effects of treatment formats on fitness indicators

Inappropriately high weight in children is a persistent problem in the United States, and physical activity is often reduced in schools due to academic demands. Effective after-school programs could positively impact both physical activity and overweight/obesity, however previous reviews and meta-analyses have indicated minimal effects. Both 4- and 3-day/week versions of a social cognitive theory-driven physical activity/nutrition after-school program were evaluated against unstructured care to assess effects in children (overall M_age = 10.00 years, SD = .80). For changes over 9 months in body mass index (BMI), effects sizes (Cohen's d) were .68, .40, and .07 in the 4-day (n = 70), 3-day (n = 70), and unstructured (n = 50) groups, respectively. Similar patterns of effects were found for changes in free-time physical activity and cardiovascular endurance. Incorporating a theory-based prediction model previously supported in teens through older adults, with and without medical disorders and health-risk factors, improvements in exercise-related self-regulation and self-efficacy, and mood, significantly predicted increased free-time physical activity (R² = .48). Effects significantly strengthened to R² = .62 when completion/non-completion of the recommended 300 min/week of physical activity was also accounted for. Change in BMI was inversely related to physical activity change, β=-.14, p < .05. The present evaluation process indicated promising effects, and indicated theory-based targets to foster future program improvements.

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.

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.

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

CONTEXT

For decades, behavioral weight-loss treatments have been unsuccessful beyond the short term. Development and testing of innovative, theoretically based methods that depart from current failed practices is a priority for behavioral medicine.

OBJECTIVE

To evaluate a new, theory-based protocol in which exercise support methods are employed to facilitate improvements in psychosocial predictors of controlled eating and sustained weight loss.

METHODS

Women with obesity were randomized into either a comparison treatment that incorporated a print manual plus telephone follow-ups (n = 55) or an experimental treatment of The Coach Approach exercise-support protocol followed after 2 months by group nutrition sessions focused on generalizing self-regulatory skills from an exercise support to a controlled eating context (n = 55). Repeated-measures analysis of variance contrasted group changes in weight, physical activity, fruit and vegetable intake, mood, and exercise- and eating-related self-regulation and self-efficacy over 24 months. Regression analyses determined salient interrelations of change scores over both the weight-loss phase (baseline-month 6) and weight-loss maintenance phase (month 6-month 24).

RESULTS

Improvements in all psychological measures, physical activity, and fruit and vegetable intake were significantly greater in the experimental group where a mean weight loss of 5.7 kg (6.1% of initial body weight) occurred at month 6, and was largely maintained at a loss of 5.1 kg (5.4%) through the full 24 months of the study. After establishing temporal intervals for changes in self-regulation, self-efficacy, and mood that best predicted improvements in physical activity and eating, a consolidated multiple mediation model suggested that change in self-regulation best predicted weight loss, whereas change in self-efficacy best predicted maintenance of lost weight.

CONCLUSIONS

Because for most participants loss of weight remained greater than that required for health benefits, and costs for treatment administration were comparatively low, the experimental protocol was considered successful. After sufficient replication, physician referral and applications within health promotion and wellness settings should be considered.