A Randomized Effectiveness Trial of a Dissonance‐Based Dual Obesity and Eating Disorder Prevention Program

Aims Evaluate the effectiveness of Project Health , a dual obesity and eating disorder prevention program, relative to an educational video control condition and conduct an exploratory test of whether adding evaluative conditioning to the response/attention training component enhances intervention effects. Materials and Methods 138 young adults ( M age = 19.4; 76% female; 58% White) were randomized to Project Health groups or an educational video control condition. Results Participants randomized to Project Health showed greater decreases in body fat at posttest ( d = −0.23) and 6‐month follow‐up ( d = −0.53) than educational video controls. Intervention effects on change in eating disorder symptoms were nonsignificant at posttest ( d = −0.14) but significant at 6‐month follow‐up ( d = −0.33). Adding evaluative conditioning to the food response/attention training significantly enhanced the body fat loss effects at posttest ( d = −0.36), but not at 6‐month follow‐up ( d = −0.13); there were significant eating disorder symptom reduction effects by posttest ( d = −0.37), but not at 6‐month follow‐up ( d = 0.18). Conclusions Project Health produced greater body fat loss/weight gain prevention effects than control participants. However, it only produced marginally greater reductions in eating disorder symptoms, in contrast to past trials. Evaluative conditioning enhanced the body fat loss effects of the food response/attention training element of Project Health. Trial Registration: ClinicalTrials.gov identifier: NCT06067763.