Jutta Mata

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.

Public Knowledge of Benefits of Breast and Prostate Cancer Screening in Europe

Making informed decisions about breast and prostate cancer screening requires knowledge of its benefits. However, country-specific information on public knowledge of the benefits of screening is lacking. Face-to-face computer-assisted personal interviews were conducted with 10 228 persons selected by a representative quota method in nine European countries (Austria, France, Germany, Italy, the Netherlands, Poland, Russia, Spain, and the United Kingdom) to assess perceptions of cancer-specific mortality reduction associated with mammography and prostate-specific antigen (PSA) screening. Participants were also queried on the extent to which they consulted 14 different sources of health information. Correlation coefficients between frequency of use of particular sources and the accuracy of estimates of screening benefit were calculated. Ninety-two percent of women overestimated the mortality reduction from mammography screening by at least one order of magnitude or reported that they did not know. Eighty-nine percent of men overestimated the benefits of PSA screening by a similar extent or did not know. Women and men aged 50–69 years, and thus targeted by screening programs, were not substantially better informed about the benefits of mammography and PSA screening, respectively, than men and women overall. Frequent consulting of physicians (r = .07, 95% confidence interval [CI] = 0.05 to 0.09) and health pamphlets (r = .06, 95% CI = 0.04 to 0.08) tended to increase rather than reduce overestimation. The vast majority of citizens in nine European countries systematically overestimate the benefits of mammography and PSA screening. In the countries investigated, physicians and other information sources appear to have little impact on improving citizens’ perceptions of these benefits.

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.

Motivation, self-determination, and long-term weight control

This article explores the topics of motivation and self-regulation in the context of weight management and related behaviors. We focus on the role of a qualitative approach to address motivation - not only considering the level but also type of motivation - in weight control and related behaviors. We critically discuss the operationalization of motivation in current weight control programs, present a complementary approach to understanding motivation based on self-determination theory, and review empirical findings from weight control studies that have used self-determination theory measures and assessed their association with weight outcomes. Weight loss studies which used Motivational Interviewing (MI) are also reviewed, considering MIs focus on enhancing internal motivation. We hypothesize that current weight control interventions may have been less successful with weight maintenance in part due to their relative disregard of qualitative dimensions of motivation, such as level of perceived autonomy, often resulting in a motivational disconnect between weight loss and weight-related behaviors. We suggest that if individuals fully endorse weight loss-related behavioral goals and feel not just competent but also autonomous about reaching them, as suggested by self-determination theory, their efforts are more likely to result in long-lasting behavior change.

Walk on the bright side: physical activity and affect in major depressive disorder.

Although prescribed exercise has been found to improve affect and reduce levels of depression, we do not know how self-initiated everyday physical activity influences levels of positive affect (PA) and negative affect (NA) in depressed persons. Fifty-three individuals diagnosed with Major Depressive Disorder (MDD) and 53 never-depressed controls participated in a seven-day experience sampling study. Participants were prompted randomly eight times per day and answered questions about their physical activity and affective state. Over the week, the two groups of participants did not differ in average level of physical activity. As expected, participants with MDD reported lower average PA and higher average NA than did never-depressed controls. Both participants with MDD and controls reported higher levels of PA at prompts after physical activity than at prompts after inactive periods; moreover, for both groups of participants, PA increased from a prompt after an inactive period to a subsequent prompt at which activity was reported. Depressed participants in particular showed a dose-response effect of physical activity on affect: longer duration and/or higher intensity of physical activity increased their PA significantly more than did short duration and/or lower intensity physical activity. Physical activity did not influence NA in either group. In contrast to previous treatment studies that examined the effects of prescribed structured exercise, this investigation showed that self-initiated physical activity influences PA. These findings also underscore the importance of distinguishing between PA and NA to gain a more comprehensive understanding of the effects of physical activity on affect in MDD.

The Everyday Emotional Experience of Adults with Major Depressive Disorder: Examining Emotional Instability, Inertia, and Reactivity

Investigators have begun to examine the temporal dynamics of affect in individuals diagnosed with major depressive disorder (MDD), focusing on instability, inertia, and reactivity of emotion. How these dynamics differ between individuals with MDD and healthy controls have not before been examined in a single study. In this study, 53 adults with MDD and 53 healthy adults carried hand-held electronic devices for approximately 7 days and were prompted randomly 8 times per day to report their levels of current negative affect (NA), positive affect (PA), and the occurrence of significant events. In terms of NA, compared with healthy controls, depressed participants reported greater instability and greater reactivity to positive events, but comparable levels of inertia and reactivity to negative events. Neither average levels of NA nor NA reactivity to, frequency or intensity of, events accounted for the group difference in instability of NA. In terms of PA, the MDD and control groups did not differ significantly in their instability, inertia, or reactivity to positive or negative events. These findings highlight the importance of emotional instability in MDD, particularly with respect to NA, and contribute to a more nuanced understanding of the everyday emotional experiences of depressed individuals.

BDNF genotype moderates the relation between physical activity and depressive symptoms.

OBJECTIVE To test whether the BDNF gene interacts with exercise to predict depressive symptoms. Physical activity is associated with a range of positive health outcomes, including fewer depressive symptoms. One plausible mechanism underlying these findings involves Brain-Derived Neurotrophic Factor (BDNF), a protein hypothesized to limit or repair the damage caused by stress. Physical activity increases expression of BDNF, which may enhance brain health. BDNF expression is controlled by the BDNF gene. Compared with individuals without a BDNF met allele, met-allele carriers have a lower expression of BDNF, which has been associated with Major Depressive Disorder. DESIGN Eighty-two healthy adolescent girls were genotyped for the BDNF val66met polymorphism, and their depressive symptoms and physical activity were assessed using questionnaires. MAIN OUTCOME MEASURES BDNF genotype, Childrens Depression Inventory, and the Physical Activity Questionnaire for Older Children and Adolescents. RESULTS The BDNF polymorphism was found to moderate the relation between exercise and depressive symptoms: being physically active was protective for girls with a BDNF met allele (fewer depressive symptoms) but not for girls with the val/val polymorphism. CONCLUSION By integrating psychological and biological factors, the present study enhances our understanding of how physical activity contributes to resilience to psychopathology.

Exercise holds immediate benefits for affect and cognition in younger and older adults.

Physical activity is associated with improved affective experience and enhanced cognitive processing. Potential age differences in the degree of benefit, however, are poorly understood because most studies examine either younger or older adults. The present study examined age differences in cognitive performance and affective experience immediately following a single bout of moderate exercise. Participants (144 community members aged 19 to 93) were randomly assigned to one of two experimental conditions: (a) exercise (15 min of moderate intensity stationary cycling) or (b) control (15 min completing ratings of neutral IAPS images). Before and after the manipulation, participants completed tests of working memory and momentary affect experience was measured. Results suggest that exercise is associated with increased levels of high-arousal positive affect (HAP) and decreased levels of low-arousal positive affect (LAP) relative to control condition. Age moderated the effects of exercise on LAP, such that younger age was associated with a drop in reported LAP postexercise, whereas the effects of exercise on HAP were consistent across age. Exercise also led to faster RTs on a working memory task than the control condition across age. Self-reported negative affect was unchanged. Overall, findings suggest that exercise may hold important benefits for both affective experience and cognitive performance regardless of age.

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.

Emotion-Network Density in Major Depressive Disorder

Major depressive disorder (MDD) is a prevalent disorder involving disturbances in mood. There is still much to understand regarding precisely how emotions are disrupted in individuals with MDD. In this study, we used a network approach to examine the emotional disturbances underlying MDD. We hypothesized that compared with healthy control individuals, individuals diagnosed with MDD would be characterized by a denser emotion network, thereby indicating that their emotion system is more resistant to change. Indeed, results from a 7-day experience sampling study revealed that individuals with MDD had a denser overall emotion network than did healthy control individuals. Moreover, this difference was driven primarily by a denser negative, but not positive, network in MDD participants. These findings suggest that the disruption in emotions that characterizes depressed individuals stems from a negative emotion system that is resistant to change.