Effect of 8 weeks of supervised overfeeding on eating attitudes and behaviors, eating disorder symptoms, and body image: Results from the PROOF and EAT studies.

The physiological and metabolic effects of experimental overfeeding have been extensively studied, yet only few studies have assessed overfeeding effects on eating behaviors and psychological constructs. We analyzed two 8-week overfeeding studies, the PROOF Study (N = 25; 16 males; 16 African American; 24.1 years; 25.1 kg/m2, inpatient) and the EAT Study (N = 35; 29 males; 20 White; 26.7 years; 25.5 kg/m2, free-living). In both studies, participants were overfed 40% above baseline (daily) energy requirements for eight weeks, consuming all meals under direct supervision. We assessed eating attitudes and behaviors, eating disorder symptoms, and body image via validated questionnaires and visual analog scales at baseline, week (W) 4, and W8, and at two (PROOF: W16-Post, W24-Post) and three (EAT: W12-Post, W20-Post, W32-Post) follow-up visits, respectively. Hunger, desire to eat, and food cravings (carbohydrates, total cravings) decreased during overfeeding in both studies (all Cohen's d effect sizes ≥0.3, all p ≤ .048). Depressive symptoms and fear of fatness increased in both studies (all Cohen's d ≥ 0.4, p ≤ .020), though they were still within normal limits (t-scores ~43-49). Body dissatisfaction increased in both studies during overfeeding (all Cohen's d ≥ 0.4, all p ≤ .044) and remained increased during follow-up (PROOF: W16-Post, Cohen's d = 0.9, p = .004; EAT: W12-Post and W20-Post, all Cohen's d ≥ 0.4, all p ≤ .037). Overfeeding was associated with some deleterious effects, though most returned to baseline during follow-up. However, increases in body dissatisfaction remained up to three months post-overfeeding, highlighting the need to address body image disturbance among people who experience weight gain, even if much of the gained weight is subsequently lost. TRIAL REGISTRATION: The PROOF Study (ClinicalTrials.gov Identifier NCT00565149); the EAT Study (ClinicalTrials.gov Identifier NCT01672632).