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 +/- 4.1 kg/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. (C) 2010 Elsevier Ireland Ltd. All rights reserved.