Sílvia R. Coutinho

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/m2) 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 (R2 = 0.31, P < 0.001; effect ratio: 0.37), but only flexible restraint and exercise self‐efficacy mediated 24‐month weight loss (R2 = 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.

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

BackgroundResearch 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 SDTs utility in facilitating and explaining health behavior change, especially physical activity/exercise, during obesity treatment.MethodsStudy 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.DiscussionResults 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 RegistrationClinical Trials Gov. Identifier NCT00513084

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.

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 theorys 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.

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 ones 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.

Success in maintaining weight loss in Portugal: The Portuguese Weight Control Registry

O objetivo deste trabalho e descrever a metodologia do Registo Nacional de Controlo do Peso e descrever os participantes quanto a sua historia individual e familiar relacionada com o peso, tentativas anteriores de reducao deste e caraterizacao psicossocial. A amostra inclui 198 adultos (idade: 39,7 ± 11,1anos; IMC: 26,0 ± 3,9kg/m2), 59% mulheres, que completaram um questionario abordando questoes demograficas, motivacoes e atitudes, e estrategias de perda e de manutencao do peso. Os participantes reportaram uma perda do peso media de 17,4kg e uma duracao media de manutencao do peso perdido de 29 meses. Relativamente ao numero de tentativas de reducao do peso reportadas, 73% indicou ter iniciado uma dieta no maximo por tres vezes e 34% reportou ter tentado perder peso apenas uma vez no passado. Este estudo ira permitir conhecer com mais detalhe e representatividade as carateristicas e as estrategias adoptadas por estas pessoas bem sucedidas na manutencao do peso perdido no longo prazo e contribuir para identificar variaveis preditoras da gestao bem sucedida do peso a longo prazo.The scope of this article is to describe the Portuguese Weight Control Registry (PWCR) methodology and the participants currently enrolled specifically with respect to their individual and family weight history, previous weight loss attempts, and psychosocial characteristics. One hundred and ninety-eight adults (age: 39.7±11.1 years; BMI: 26.0±3.9 kg/m2), 59% women, filled out a questionnaire about demographics, health-related behaviors and motivation, and methods and strategies used to lose and/or maintain weight loss. Participants reported an average weight loss of 17.4 kg for an average of 29 months. Concerning the number of weight loss attempts, 73% of participants reported a maximum of three attempts of going on a diet, and 34% indicated only one attempt to lose weight in the past. The PWCR now features a considerable number of successful long-term weight loss maintainers in Portugal. Participants will be followed over the next years to learn about their characteristics and weight loss strategies in further detail, as well as to identify predictors of continued weight loss maintenance.

Sucesso na manutenção do peso perdido em Portugal o Registo Nacional de Controlo do Peso

O objetivo deste trabalho e descrever a metodologia do Registo Nacional de Controlo do Peso e descrever os participantes quanto a sua historia individual e familiar relacionada com o peso, tentativas anteriores de reducao deste e caraterizacao psicossocial. A amostra inclui 198 adultos (idade: 39,7 ± 11,1anos; IMC: 26,0 ± 3,9kg/m2), 59% mulheres, que completaram um questionario abordando questoes demograficas, motivacoes e atitudes, e estrategias de perda e de manutencao do peso. Os participantes reportaram uma perda do peso media de 17,4kg e uma duracao media de manutencao do peso perdido de 29 meses. Relativamente ao numero de tentativas de reducao do peso reportadas, 73% indicou ter iniciado uma dieta no maximo por tres vezes e 34% reportou ter tentado perder peso apenas uma vez no passado. Este estudo ira permitir conhecer com mais detalhe e representatividade as carateristicas e as estrategias adoptadas por estas pessoas bem sucedidas na manutencao do peso perdido no longo prazo e contribuir para identificar variaveis preditoras da gestao bem sucedida do peso a longo prazo.The scope of this article is to describe the Portuguese Weight Control Registry (PWCR) methodology and the participants currently enrolled specifically with respect to their individual and family weight history, previous weight loss attempts, and psychosocial characteristics. One hundred and ninety-eight adults (age: 39.7±11.1 years; BMI: 26.0±3.9 kg/m2), 59% women, filled out a questionnaire about demographics, health-related behaviors and motivation, and methods and strategies used to lose and/or maintain weight loss. Participants reported an average weight loss of 17.4 kg for an average of 29 months. Concerning the number of weight loss attempts, 73% of participants reported a maximum of three attempts of going on a diet, and 34% indicated only one attempt to lose weight in the past. The PWCR now features a considerable number of successful long-term weight loss maintainers in Portugal. Participants will be followed over the next years to learn about their characteristics and weight loss strategies in further detail, as well as to identify predictors of continued weight loss maintenance.

Sucesso na manutenção do peso perdido em Portugal

O objetivo deste trabalho e descrever a metodologia do Registo Nacional de Controlo do Peso e descrever os participantes quanto a sua historia individual e familiar relacionada com o peso, tentativas anteriores de reducao deste e caraterizacao psicossocial. A amostra inclui 198 adultos (idade: 39,7 ± 11,1anos; IMC: 26,0 ± 3,9kg/m2), 59% mulheres, que completaram um questionario abordando questoes demograficas, motivacoes e atitudes, e estrategias de perda e de manutencao do peso. Os participantes reportaram uma perda do peso media de 17,4kg e uma duracao media de manutencao do peso perdido de 29 meses. Relativamente ao numero de tentativas de reducao do peso reportadas, 73% indicou ter iniciado uma dieta no maximo por tres vezes e 34% reportou ter tentado perder peso apenas uma vez no passado. Este estudo ira permitir conhecer com mais detalhe e representatividade as carateristicas e as estrategias adoptadas por estas pessoas bem sucedidas na manutencao do peso perdido no longo prazo e contribuir para identificar variaveis preditoras da gestao bem sucedida do peso a longo prazo.The scope of this article is to describe the Portuguese Weight Control Registry (PWCR) methodology and the participants currently enrolled specifically with respect to their individual and family weight history, previous weight loss attempts, and psychosocial characteristics. One hundred and ninety-eight adults (age: 39.7±11.1 years; BMI: 26.0±3.9 kg/m2), 59% women, filled out a questionnaire about demographics, health-related behaviors and motivation, and methods and strategies used to lose and/or maintain weight loss. Participants reported an average weight loss of 17.4 kg for an average of 29 months. Concerning the number of weight loss attempts, 73% of participants reported a maximum of three attempts of going on a diet, and 34% indicated only one attempt to lose weight in the past. The PWCR now features a considerable number of successful long-term weight loss maintainers in Portugal. Participants will be followed over the next years to learn about their characteristics and weight loss strategies in further detail, as well as to identify predictors of continued weight loss maintenance.

Success in maintaining weight loss in Portugal

O objetivo deste trabalho e descrever a metodologia do Registo Nacional de Controlo do Peso e descrever os participantes quanto a sua historia individual e familiar relacionada com o peso, tentativas anteriores de reducao deste e caraterizacao psicossocial. A amostra inclui 198 adultos (idade: 39,7 ± 11,1anos; IMC: 26,0 ± 3,9kg/m2), 59% mulheres, que completaram um questionario abordando questoes demograficas, motivacoes e atitudes, e estrategias de perda e de manutencao do peso. Os participantes reportaram uma perda do peso media de 17,4kg e uma duracao media de manutencao do peso perdido de 29 meses. Relativamente ao numero de tentativas de reducao do peso reportadas, 73% indicou ter iniciado uma dieta no maximo por tres vezes e 34% reportou ter tentado perder peso apenas uma vez no passado. Este estudo ira permitir conhecer com mais detalhe e representatividade as carateristicas e as estrategias adoptadas por estas pessoas bem sucedidas na manutencao do peso perdido no longo prazo e contribuir para identificar variaveis preditoras da gestao bem sucedida do peso a longo prazo.The scope of this article is to describe the Portuguese Weight Control Registry (PWCR) methodology and the participants currently enrolled specifically with respect to their individual and family weight history, previous weight loss attempts, and psychosocial characteristics. One hundred and ninety-eight adults (age: 39.7±11.1 years; BMI: 26.0±3.9 kg/m2), 59% women, filled out a questionnaire about demographics, health-related behaviors and motivation, and methods and strategies used to lose and/or maintain weight loss. Participants reported an average weight loss of 17.4 kg for an average of 29 months. Concerning the number of weight loss attempts, 73% of participants reported a maximum of three attempts of going on a diet, and 34% indicated only one attempt to lose weight in the past. The PWCR now features a considerable number of successful long-term weight loss maintainers in Portugal. Participants will be followed over the next years to learn about their characteristics and weight loss strategies in further detail, as well as to identify predictors of continued weight loss maintenance.