Sex Differences in Early Weight Loss Success During a Diabetes Prevention Intervention.

Objectives: Males often lose more weight than females during treatment, and early weight loss predicts weight loss longer-term. Yet, mechanisms for sex differences in early weight loss are unknown and were examined in this study.Methods: Adults≥21 years old with overweight or obesity and prediabetes (N=206) participated in a lifestyle intervention and completed baseline psychosocial questionnaires. Percent weight loss, session attendance, and number of days participants self-monitored dietary intake and weight were determined at week 5. Principal components, regression, and mediation analyses were conducted to determine whether weight loss differed by sex and potential mediators of weight change. Results: Mean (±SD) weight loss was greater for males (2.59±1.62%) than females (2.05±1.54%; p=.02). Attendance, self-monitoring, and beliefs regarding disease risk were independent predictors of weight loss (all p<.05) but did not explain sex differences. The association between attendance and weight loss was stronger for males than females (p<.05). Conclusions: Additional research is needed to identify mechanisms that explain sex differences in early weight loss. However, strengthening risk beliefs, attendance, and self-monitoring may promote greater early weight loss for all participants.