Temporal aspects of psychosocial predictors of increased fruit and vegetable intake in adults with severe obesity: mediation by physical activity.

Effective and reliable obesity treatments are lacking because of a poor understanding of the health behavior change process. Community-based organizations with the capacity to train existing staff members are particularly well-positioned to implement evidence-based treatment protocols to impact obesity-related behaviors such as unhealthy eating and lack of physical activity. The aim of this study was to assess temporal aspects of psychosocial predictors (self-regulation, mood, and self-efficacy) on increased fruit and vegetable intake in adults with severe obesity, while also accounting for mediation by physical activity volume. A 6-month, randomized field investigation was conducted. Severely obese adults volunteered for behavioral support of physical activity coupled with nutrition education (n = 73) or cognitive-behavioral methods for nutrition change (n = 71). Improvements in self-regulation, mood, self-efficacy, fruit and vegetable intake (FV), and physical activity (PA) were significant, with significantly greater self-regulation at month 6 for the cognitive-behavioral group. Increase in FV was predicted by changes in the above psychosocial variables over 6 months, with mood change over 3 months also a significant predictor. Change in PA mediated the above relationships, with a reciprocal effect between changes in PA and FV. Findings have implications for the large-scale behavioral treatment of obesity.