Weight control behaviors of highly successful weight loss maintainers: the Portuguese Weight Control Registry.

To describe key behaviors reported by participants in the Portuguese Weight Control Registry and to determine associations between these behaviors and weight loss maintenance. A total of 388 adults participated in this cross-sectional study. Assessments included demographic information, weight history, weight loss and weight maintenance strategies, dietary intake, and physical activity. Participants lost on average 18 kg, which they had maintained for ~28 months. Their average dietary intake was 2199 kcal/day, with 33 % of energy coming from fat. About 78 % of participants engaged in levels of moderate-plus-vigorous physical activity exceeding 150 min/week (51 % above 250 min/week), with men accumulating 82 more minutes than women (p < 0.05). The most frequently reported strategies for both weight loss and maintenance were keeping healthy foods at home, consuming vegetables regularly, and having daily breakfast. Greater weight loss maintenance was associated with higher levels of physical activity, walking, weight self-monitoring, establishing specific goals, and with reduced portion size use, reduced consumption of carbohydrates, and increased consumption of protein, (p < 0.05). Results indicate that weight loss maintenance is possible through the adoption of a nutritionally-balanced diet and regular participation in physical activity, but also suggest that adopting different (and, to a degree, individualized) set of behavioral strategies is key for achieving success.

The association between physical activity and eating self-regulation in overweight and obese women.

OBJECTIVE: Successful weight management relies heavily on eating and exercise behaviors. However, little is known about the association between both on a psychosocial level. This study examined the relationship between exercise and eating regulation by exploring the mediating effects of negative body image investment and depressive mood, and their stability through time. METHODS: Analyses were conducted at two different moments (12 and 36 months), involving a sample of 221 overweight/obese women (age: 37.6 ± 7 years; BMI: 31.6 ± 4.1 kg/m(2)) that participated in a behavioral weight control intervention. Bivariate correlations and mediation analyses using Preacher & Hayes resampling procedures were conducted. RESULTS: At 12 months, negative body image investment was the only significant mediator of the exercise-eating relationship. This variable explained larger portions of the indirect effects of structured rather than lifestyle exercise on eating. At 36 months, negative investment and to a lesser extent depressive mood partially explained the exercise-eating association. CONCLUSIONS: Our findings suggest that, besides physiological effects of exercise, psychological mechanisms related to body image and mood also explain the role of physical activity as a 'gateway behavior' for improved eating regulation in overweight women. These effects appear to be stable and may help understand the key role of exercise in long-term weight management.

Correlates of health-related quality of life, psychological well-being, and eating self-regulation after successful weight loss maintenance.

The purpose of this study was to evaluate health-related quality of life and other psychosocial characteristics, including eating self-regulation and body image, in a group of successful long-term weight loss maintainers. Women enrolled in the Portuguese Weight Control Registry (n = 107) were matched and compared to women at the end of a behavior weight loss treatment program (n = 107), and also with women in the community who were not trying to lose weight (n = 107). Successful maintainers displayed higher quality of life and a more positive profile in selected eating and exercise markers of self-regulation compared to similarly-weighed women not attempting weight loss, but not when compared to the 'weight loss treatment' group. However, results also suggest that concerns with body shape and size may persist after weight loss and that some aspects of well-being and eating self-regulation can be more successfully targeted in specific weight loss programs.

Usefulness of standard BMI cut-offs for quality of life and psychological well-being in women.

OBJECTIVE: We examined BMI-based obesity categories and risk for poor health-related quality of life (HRQOL) and psychological well-being (PWB). METHODS: Participants were 1,795 women aged 35.3 ± 10.2 years with a mean BMI of 26.6 kg/m(2), not seeking treatment (55%) or upon entry into a weight control program. Assessments included general HRQOL, weight-related HRQOL, self-esteem, and body image. RESULTS: All variables, except general HRQOL, were different (p < 0.001) between normal-weight and overweight/obese women. For weight-related HRQOL and body image, worse psychosocial scores were observed linearly with higher obesity levels. Self-esteem was lower in overweight and obese women in comparison with normal-weight women, with no difference between class I and class II obesity. Participants entering a clinical program reported higher physical HRQOL, but lower self-esteem and poorer body image than community-dwelling women of equal weight. CONCLUSIONS: BMI categories are useful for identifying increased impairment in PWB and HRQOL in overweight and obese (class I or II) women. Women with a BMI under 25 kg/m(2) reported improved well-being and HRQOL in comparison to overweight or obese women. However, this relation may not be linear across all psychosocial outcomes, with unique patterns emerging for the association of obesity level with specific dimensions of PWB and HRQOL.

Physical activity predicts changes in body image during obesity treatment in women.

PURPOSE: This study examined effects of a behavioral weight management intervention on body image (evaluative and investment dimensions) and explored the potential mediating role of structured and lifestyle physical activity (PA). METHODS: The study was a longitudinal randomized controlled trial, including a 1-yr behavior change intervention and a 2-yr follow-up (225 women, 37.6 ± 7 yr, body mass index = 31.5 ± 4.1 kg·m). Statistical analyses comprised mixed-design ANOVAs with repeated measures, bivariate/partial correlations, and mediation analyses. RESULTS: Body image improved considerably in both groups, favoring the intervention group (small to moderate effect sizes: 0.03-0.05), but began to deteriorate from 12 to 24 months, especially in the intervention group. Consequently, at 24 months, between-group differences were small and did not reach significance. Yet, levels of body dissatisfaction and dysfunctional investment remained below initial values (for both groups). Results were similar for both body image dimensions. Structured PA (at 12 and 24 months) and lifestyle PA (at 24 months) were positively associated with (r > -0.25, P < 0.05) and partially mediated body image improvements, especially in the investment component (95% confidence interval of -1.88 to -0.27 for structured PA at 12 months, 95% confidence interval of -1.94 to -0.21 for lifestyle PA at 24 months). In general, change in evaluative body image was not mediated by exercise participation, seeming more dependent on weight change. CONCLUSIONS: These findings highlight the importance of PA as a contributing factor in the improvement of body image in overweight/obese women, mainly by reducing excessive salience of appearance to one's life and self. Lifestyle PA may also be a valid option, particularly in the long term. Exercise might provide a buffer against body image deterioration overtime, favoring lasting weight loss maintenance.

Body image change and improved eating self-regulation in a weight management intervention in women.

BACKGROUND: Successful weight management involves the regulation of eating behavior. However, the specific mechanisms underlying its successful regulation remain unclear. This study examined one potential mechanism by testing a model in which improved body image mediated the effects of obesity treatment on eating self-regulation. Further, this study explored the role of different body image components. METHODS: Participants were 239 overweight women (age: 37.6 ± 7.1 yr; BMI: 31.5 ± 4.1 kg/m²) engaged in a 12-month behavioral weight management program, which included a body image module. Self-reported measures were used to assess evaluative and investment body image, and eating behavior. Measurements occurred at baseline and at 12 months. Baseline-residualized scores were calculated to report change in the dependent variables. The model was tested using partial least squares analysis. RESULTS: The model explained 18-44% of the variance in the dependent variables. Treatment significantly improved both body image components, particularly by decreasing its investment component (f² = .32 vs. f² = .22). Eating behavior was positively predicted by investment body image change (p < .001) and to a lesser extent by evaluative body image (p < .05). Treatment had significant effects on 12-month eating behavior change, which were fully mediated by investment and partially mediated by evaluative body image (effect ratios: .68 and .22, respectively). CONCLUSIONS: Results suggest that improving body image, particularly by reducing its salience in one's personal life, might play a role in enhancing eating self-regulation during weight control. Accordingly, future weight loss interventions could benefit from proactively addressing body image-related issues as part of their protocols.

Exercise autonomous motivation predicts 3-yr weight loss in women.

PURPOSE: This study evaluated exercise-related predictors of successful long-term weight control in women by analyzing the extent to which sustained exercise participation and self-determination theory (SDT)-based exercise motivation variables mediated the impact of a behavioral weight control intervention on 3-yr weight change. METHODS: Longitudinal randomized controlled trial consisting of a 1-yr SDT-based intervention and a 2-yr follow-up with 221 female participants (means ± SD: age = 37.6 ± 7 yr, body mass index = 31.6 ± 4.1 kg·m(-2)). The tested model incorporated experimentally manipulated perceived need support, motivational regulations, and 2-yr exercise adherence as mediators of the intervention's impact on 3-yr weight change. Paths were tested using partial least squares analysis. Where there were significant intervening paths, tests of mediation were conducted. RESULTS: Treatment had significant effects on 1- and 2-yr autonomous regulations, 2-yr physical activity, and 3-yr weight change, fully mediated by the tested paths (effect ratio = 0.10-0.61). Moderate and vigorous exercise at 2 yr had a significant effect (P < 0.001) on weight loss success at 3 yr and partially mediated the effect of treatment on weight change. The 2-yr autonomous regulation effects on follow-up weight change were only partially mediated by physical activity (effect ratio = 0.42). CONCLUSIONS: This application of SDT to physical activity and weight management showed that not all types of motivation predict long-term behavioral outcomes and that sustained moderate and vigorous exercise mediated long-term weight change. It provides strong evidence for a link between experimentally increased autonomous motivation and exercise and long-term weight loss maintenance. Results highlight the importance of interventions targeting the internalization of exercise behavioral regulation and making exercise and physical activity positive and meaningful experiences rather than simply focusing on immediate behavior change in overweight/obese women.

Predictors of Psychological Well-Being during Behavioral Obesity Treatment in Women.

This study examined the association of autonomy-related variables, including exercise motivation, with psychological well-being and quality of life, during obesity treatment. Middle-aged overweight/obese women (n = 239) participated in a 1-year behavioral program and completed questionnaires measuring need support, general self-determination, and exercise and treatment motivation. General and obesity-specific health-related quality of life (HRQOL), self-esteem, depression, and anxiety were also assessed. Results showed positive correlations of self-determination and perceived need support with HRQOL and self-esteem, and negative associations with depression and anxiety (P < .001). Treatment autonomous motivation correlated positively with physical (P = .004) and weight-related HRQOL (P < .001), and negatively with depression (P = .025) and anxiety (P = .001). Exercise autonomous motivation was positively correlated with physical HRQOL (P < .001), mental HRQOL (P = .003), weight-related HRQOL (P < .001), and self-esteem (P = .003), and negatively with anxiety (P = .016). Findings confirm that self-determination theory's predictions apply to this population and setting, showing that self-determination, perceived need support, and autonomous self-regulation positively predict HRQOL and psychological well-being.

Change in body image and psychological well-being during behavioral obesity treatment: Associations with weight loss and maintenance.

This study reports on outcomes from a behavioral obesity treatment program, evaluating if treatment-related changes in body image and psychological well-being are predictors of weight change during treatment and after follow-up. Participants were 142 overweight/obese women (BMI=30.2+/-3.7kg/m(2); age=38.3+/-5.8 years) participants in a behavioral treatment program consisting of a 4-month treatment period and a 12-month follow-up. Psychosocial variables improved during treatment and these changes were correlated with 4-month weight reduction. Short-term changes in body size dissatisfaction (p=.002) and mood (p=.003) predicted long-term weight loss. Additional results suggest that there might be a predictive role of short-term changes in body size dissatisfaction and self-esteem on long-term weight loss after accounting for initial weight change (p<.028). We conclude that, along with weight changes, cognitive and affect-related processes influenced during obesity treatment may be related long-term success, in some cases independently of initial weight loss.

The effect of physical activity on weight loss is mediated by eating self-regulation.

OBJECTIVE: This study tested whether different forms of physical activity (PA) were associated with eating self-regulation during weight control, and if changes in eating behavior mediated the relationship between PA and weight loss, in overweight/obese women. METHODS: 239 women (37.6+/-7.0 years; 31.3+/-4.1kg/m(2)) participated. The intervention group received a 12-month group behavioral treatment designed to increase autonomy and self-regulation for weight control. Controls received a health education program. Assessments included body weight, structured and lifestyle exercise/PA, and eating self-regulation. RESULTS: Moderate+vigorous and lifestyle PA were associated with 12-month change in most eating variables (p<0.05) and with body weight change (p<0.01). Mediation analysis showed that flexible cognitive restraint and emotional eating fully mediated the relation between lifestyle PA and weight change (effect ratio: 0.63). About 34% of the effect of moderate+vigorous PA on weight change was explained by these same mediators (partial mediation). CONCLUSION: Exercise and PA may positively influence weight control through eating self-regulation. Flexible dietary control and reduced emotional overeating are mechanisms by which an active lifestyle can contribute to long-term weight management. PRACTICE IMPLICATIONS: Regular exercise and PA can contribute to improved eating behaviors during weight management. This could represent an important incentive for people seeking weight control.

Using self-determination theory to promote physical activity and weight control: a randomized controlled trial in women.

Behavior change interventions are effective to the extent that they affect appropriately-measured outcomes, especially in experimental controlled trials. The primary goal of this study was to analyze the impact of a 1-year weight management intervention based on self-determination theory (SDT) on theory-based psychosocial mediators, physical activity/exercise, and body weight and composition. Participants were 239 women (37.6 +/- 7.1 years; 31.5 +/- 4.1 kg/m(2)) who received either an intervention focused on promoting autonomous forms of exercise regulation and intrinsic motivation, or a general health education program (controls). At 12 months, the intervention group showed increased weight loss (-7.29%,) and higher levels of physical activity/exercise (+138 +/- 26 min/day of moderate plus vigorous exercise; +2,049 +/- 571 steps/day), compared to controls (P < 0.001). Main intervention targets such as more autonomous self-regulation (for treatment and for exercise) and a more autonomous perceived treatment climate revealed large effect sizes (between 0.80 and .96), favoring intervention (P < 0.001). Results suggest that interventions grounded in SDT can be successfully implemented in the context of weight management, enhancing the internalization of more autonomous forms of behavioral regulation, and facilitating exercise adherence, while producing clinically-significant weight reduction, when compared to a control condition. Findings are fully consistent with previous studies conducted within this theoretical framework in other areas of health behavior change.

Mediators of weight loss and weight loss maintenance in middle-aged women.

Long-term behavioral self-regulation is the hallmark of successful weight control. We tested mediators of weight loss and weight loss maintenance in middle-aged women who participated in a randomized controlled 12-month weight management intervention. Overweight and obese women (N = 225, BMI = 31.3 +/- 4.1 kg/m(2)) were randomly assigned to a control or a 1-year group intervention designed to promote autonomous self-regulation of body weight. Key exercise, eating behavior, and body image variables were assessed before and after the program, and tested as mediators of weight loss (12 months, 86% retention) and weight loss maintenance (24 months, 81% retention). Multiple mediation was employed and an intention-to-treat analysis conducted. Treatment effects were observed for all putative mediators (Effect size: 0.32-0.79, P < 0.01 vs. controls). Weight change was -7.3 +/- 5.9% (12-month) and -5.5 +/- 5.0% (24-month) in the intervention group and -1.7 +/- 5.0% and -2.2 +/- 7.5% in controls. Change in most psychosocial variables was associated with 12-month weight change, but only flexible cognitive restraint (P < 0.01), disinhibition (P < 0.05), exercise self-efficacy (P < 0.001), exercise intrinsic motivation (P < 0.01), and body dissatisfaction (P < 0.05) predicted 24-month weight change. Lower emotional eating, increased flexible cognitive restraint, and fewer exercise barriers mediated 12-month weight loss (R(2) = 0.31, P < 0.001; effect ratio: 0.37), but only flexible restraint and exercise self-efficacy mediated 24-month weight loss (R(2) = 0.17, P < 0.001; effect ratio: 0.89). This is the first study to evaluate self-regulation mediators of weight loss and 2-year weight loss maintenance, in a large sample of overweight women. Results show that lowering emotional eating and adopting a flexible dietary restraint pattern are critical for sustained weight loss. For long-term success, interventions must also be effective in promoting exercise intrinsic motivation and self-efficacy.

Motivational "spill-over" during weight control: increased self-determination and exercise intrinsic motivation predict eating self-regulation.

OBJECTIVE: Successful weight management relies on at least two health behaviors, eating and exercise. However, little is known about their interaction on a motivational and behavioral level. Based on the Hierarchical Model of Motivation the authors examined whether exercise-specific motivation can transfer to eating regulation during a lifestyle weight control program. The authors further investigated whether general, treatment-related, and exercise motivation underlie the relation between increased exercise and improved eating regulation. DESIGN: Overweight/obese women participated in a 1-year randomized controlled trial (N = 239). The intervention focused on promoting physical activity and internal motivation for exercise and weight loss, following Self-Determination Theory. The control group received general health education. MAIN OUTCOME MEASURES: General and exercise specific self-determination, eating self-regulation variables, and physical activity behavior. RESULTS: General self-determination and more autonomous exercise motivation predicted eating self-regulation over 12 months. Additionally, general and exercise self-determination fully mediated the relation between physical activity and eating self-regulation. CONCLUSION: Increased general self-determination and exercise motivation seem to facilitate improvements in eating self-regulation during weight control in women. These motivational mechanisms also underlie the relationship between improvements in exercise behavior and eating regulation.

Reciprocal effects among changes in weight, body image, and other psychological factors during behavioral obesity treatment: a mediation analysis.

BACKGROUND: Changes in body image and subjective well-being variables (e.g. self-esteem) are often reported as outcomes of obesity treatment. However, they may, in turn, also influence behavioral adherence and success in weight loss. The present study examined associations among obesity treatment-related variables, i.e., change in weight, quality of life, body image, and subjective well-being, exploring their role as both mediators and outcomes, during a behavioral obesity treatment. METHODS: Participants (BMI = 31.1 +/- 4.1 kg/m2; age = 38.4 +/- 6.7 y) were 144 women who attended a 12-month obesity treatment program and a comparison group (n = 49), who received a general health education program. The intervention included regular group meetings promoting lasting behavior changes in physical activity and dietary intake. Body image, quality of life, subjective well-being, and body weight were measured at baseline and treatment's end. Mediation was tested by multiple regression and a resampling approach to measure indirect effects. Treatment group assignment was the independent variable while changes in weight and in psychosocial variables were analyzed alternatively as mediators and as dependent variables. RESULTS: At 12 months, the intervention group had greater weight loss (-5.6 +/- 6.8% vs. -1.2 +/- 4.6%, p < .001) and larger decreases in body size dissatisfaction (effect size of 1.08 vs. .41, p < .001) than the comparison group. Significant improvements were observed in both groups for all other psychosocial variables (effect sizes ranging from .31-.75, p < .05). Mediation analysis showed that changes in body image and body weight were concurrently mediators and outcomes of treatment, suggesting reciprocal influences. Weight loss partially mediated the effect of treatment on quality of life and on self-esteem but the reciprocal effect was not observed. CONCLUSION: Changes in weight and body image may reciprocally affect each other during the course of behavioral obesity treatment. No evidence of reciprocal relationships was found for the other models under analysis; however, weight changes partially explained the effects of treatment on quality of life and self-esteem. Weight and psychosocial changes co-occur during treatment and will probably influence each other dynamically, in ways not yet adequately understood. Results from this study support the inclusion of intervention contents aimed at improving body image in weight management programs.

A randomized controlled trial to evaluate self-determination theory for exercise adherence and weight control: rationale and intervention description.

BACKGROUND: Research on the motivational model proposed by Self-Determination Theory (SDT) provides theoretically sound insights into reasons why people adopt and maintain exercise and other health behaviors, and allows for a meaningful analysis of the motivational processes involved in behavioral self-regulation. Although obesity is notoriously difficult to reverse and its recidivism is high, adopting and maintaining a physically active lifestyle is arguably the most effective strategy to counteract it in the long-term. The purposes of this study are twofold: i) to describe a 3-year randomized controlled trial (RCT) aimed at testing a novel obesity treatment program based on SDT, and ii) to present the rationale behind SDT's utility in facilitating and explaining health behavior change, especially physical activity/exercise, during obesity treatment. METHODS: Study design, recruitment, inclusion criteria, measurements, and a detailed description of the intervention (general format, goals for the participants, intervention curriculum, and main SDT strategies) are presented. The intervention consists of a 1-year group behavioral program for overweight and moderately obese women, aged 25 to 50 (and pre-menopausal), recruited from the community at large through media advertisement. Participants in the intervention group meet weekly or bi-weekly with a multidisciplinary intervention team (30 2 h sessions in total), and go through a program covering most topics considered critical for successful weight control. These topics and especially their delivery were adapted to comply with SDT and Motivational Interviewing guidelines. Comparison group receive a general health education curriculum. After the program, all subjects are follow-up for a period of 2 years. DISCUSSION: Results from this RCT will contribute to a better understanding of how motivational characteristics, particularly those related to physical activity/exercise behavioral self-regulation, influence treatment success, while exploring the utility of Self-Determination Theory for promoting health behavior change in the context of obesity. TRIAL REGISTRATION: Clinical Trials Gov. Identifier NCT00513084.