Relations of change in fruit and vegetable intake with overall energy reduction and physical activity with weight change:Assessing theory-based psychosocial mediators

Background:Increased physical activity and fruit and vegetable（FV）intake are typically suggested to counter obesity.Sustained behavior change in those areas has,however,been poor,possibly because of a lack of understanding of the effects of psychosocial factors.Using data from previous research,this study aimed to better define the role of physical activity and FV intake in short-and long-term weight loss via changes in malleable psychosocial mediators and moderators.Methods:Women who were obese（n=183;age=50.0±7.9 years;body mass index=35.2 d=3.2 kg/m2,mean±SD）and who previously participated in 3 different community-based behavioral weight-loss treatments were assessed over 2 years.Changes in FV intake,physical activity,self-regulation of physical activity and eating（aggregated）,negative mood,and weight were measured over 6 and 24 months.Results:Changes in each variable over both 6 and 24 months were significant（all p values<0.00 1）.The FV intake to the weight-related caloric intake relationship（β=-0.30,p<0.001）was significantly mediated by self-regulation change over 6 months.The physical activity to weightchange relationship（β=-0.46,p<0.001）was significantly mediated by both self-regulation and mood change over 24 months.Physical activity,itself,accounted for only 16%of weight-related caloric expenditure differences.Changes in physical activity and FV intake were each independent predictors of weight change over 24 months（overall R2=0.50,p<0.00 1）.Conclusion:Findings clarified theory-based targets for weight-management treatments and suggested that future weight-loss treatments strongly focus on developing self-regulatory skills to address barriers to behavioral changes.