Mediators of weight change in underserved patients with obesity: exploratory analyses from the PROPEL cluster-randomized trial

Background: Intensive lifestyle interventions (ILIs) stimulate weight loss in underserved patients with obesity, but the mediators of weight change are unknown. Objectives: Identify the mediators of weight change during an ILI versus usual care (UC) in underserved patients with obesity. Design: The Promoting Successful Weight Loss in Primary Care in Louisiana (PROPEL) trial randomized 18 clinics (n = 803) to either an ILI or UC for 24 months. The ILI group received an intensive lifestyle program; the UC group had routine care. Body weight was measured; further, eating behaviors (restraint, disinhibition), dietary intake (% fat intake, fruit and vegetable intake), physical activity, and weight- and health-related quality of life constructs were measured through questionnaires. Mediation analyses assessed whether questionnaire variables explained between-group variations in weight change during two periods: baseline to month 12 (n = 779) and month 12 to month 24 (n = 767). Results: The ILI induced greater weight loss at month 12 versus UC (between-group difference: -7.19 kg; 95% CI: -8.43, -6.07). Improvements in disinhibition (-0.33 kg; 95% CI: -0.55, -0.10), % fat intake (-0.25 kg; 95% CI: -0.50, -0.01), physical activity (-0.26 kg; 95% CI: -0.41 to -0.09), and subjective fatigue (-0.28 kg; 95% CI: -0.46, -0.10) at month 6 during the ILI partially explained this between-group difference. Greater weight loss occurred in the ILI at month 24, yet the ILI group gained 2.24 kg (95% CI: 1.32, 3.26) versus UC from month 12 to month 24. Change in fruit and vegetable intake (0.13 kg; 95% CI: 0.05, 0.21) partially explained this response, and no variables attenuated the weight regain of the ILI group. Conclusions: In an underserved sample, weight change induced by an ILI compared to UC was mediated by several psychological and behavioral variables. These findings could help refine weight regimens in underserved patients with obesity.     «

Background: Intensive lifestyle interventions (ILIs) stimulate weight loss in underserved patients with obesity, but the mediators of weight change are unknown. Objectives: Identify the mediators of weight change during an ILI versus usual care (UC) in underserved patients with obesity. Design: The Promoting Successful Weight Loss in Primary Care in Louisiana (PROPEL) trial randomized 18 clinics (n = 803) to either an ILI or UC for 24 months. The ILI group received an intensive lifestyle p...     »