Intensive lifestyle intervention goals can be achieved as effectively with large groups as with small groups

Abstract Objective The purpose of this study was to assess if group size is associated with weight loss outcomes among participants in an adapted diabetes prevention program. Methods Adults at high-risk ( N = 841) for CVD and diabetes were enrolled in the lifestyle intervention in 2011. Multiple logistic regression analyses were used to identify if group size (smaller group < 16 participants; larger group ≥16 participants) was independently associated with weight loss outcomes among participants. Results In the bivariate analyses, participants in the smaller groups compared to those in the larger groups were significantly more likely to have a higher baseline body mass index, to attend fewer intervention sessions, and less likely to self-monitor their fat intake for ≥14 weeks, and to have lost less weight during the core intervention (5.1 kg [SD 4.7] versus 5.8 kg [4.5]). However, analysis adjusting for age, sex, baseline BMI, achievement of the physical activity goal, number of weeks self-monitoring fat intake, and group size, found only two factors to be independently associated with achievement of the 7% weight loss goal: frequency of self-monitoring of fat intake and achievement of the physical activity goal. Conclusions Our findings indicate that intensive lifestyle intervention goals can be achieved as effectively with large or small groups.