Initial weight loss and early intervention adherence predict long-term weight loss during the PROPEL lifestyle intervention

Objective: This study tested whether initial weight change (WC), self-weighing, and adherence to the expected WC trajectory predict longer-term WC in an underserved primary-care population with obesity. Methods: Data from the intervention group (n = 452; 88% women; 74% Black; BMI 37.3 kg/m2 [SD: 4.6]) of the Promoting Successful Weight Loss in Primary Care in Louisiana trial were analyzed. Initial (2-, 4-, and 8-week) percentage WC was calculated from baseline clinic weights and daily at-home weights. Weights were considered adherent if they were on the expected WC trajectory (10% at 6 months with lower [7.5%] and upper [12.5%] bounds). Linear mixed-effects models tested whether initial WC and the number of daily and adherent weights predicted WC at 6, 12, and 24 months. Results: Percentage WC during the initial 2, 4, and 8 weeks predicted percentage WC at 6 (R2 = 0.15, R2 = 0.28, and R2 = 0.50), 12 (R2 = 0.11, R2 = 0.19, and R2 = 0.32), and 24 (R2 = 0.09, R2 = 0.11, and R2 = 0.16) months (all p < 0.01). Initial daily and adherent weights were significantly associated with WC as individual predictors, but they only marginally improved predictions beyond initial weight loss alone in multivariable models. Conclusions: These results highlight the importance of initial WC for predicting long-term WC and show that self-weighing and adherence to the expected WC trajectory can improve WC prediction