Examining Heterogeneity of Outcomes in a Weight Gain Prevention Program for Young Adults.

OBJECTIVE: This study aimed to characterize young adults who experienced significant weight gains (> 10%) over 3 years in a weight gain prevention program. METHODS: Secondary data analysis from the Study of Novel Approaches to Weight Gain Prevention (SNAP), a randomized trial comparing two self-regulation interventions and a control arm in young adults (18-35 years; BMI 21-30.9 kg/m2 ), was used. Large Gainers (≥ 10% of their body weight; n = 48), Small Gainers (2.6%-9.9%; n = 149), and Weight Stable participants (± 2.5%; n = 143) were compared on dimensions affecting weight gain. RESULTS: Differences in weight gain among the three groups were significant by year 1 and subsequently increased. Those who became Large Gainers were heavier at baseline and further below their highest weight, and they reported more weight cycling than Weight Stable, with Small Gainers intermediate. Neither study arm nor pregnancy explained weight change differences among the three groups. Large Gainers reported more depressive symptoms than Weight Stable at years 1 and 2. Large Gainers were less likely to weigh themselves at least weekly at 4 months, before differences in weight gain emerged, and at years 1 and 2. CONCLUSIONS: Large Gainers (representing almost 10% of participants) could be identified early by greater weight issues at baseline and lower use of weight gain prevention strategies.