The impact of continued intervention on weight: Five-year results from the weight loss maintenance trial

Abstract

Objective: In the Weight Loss Maintenance (WLM) Trial, a personal contact (PC) intervention sustained greater weight loss relative to a self-directed (SD) group over 30 months. This study investigated the effects of continued intervention over an additional 30 months and overall weight change across the entire WLM Trial.

Methods: WLM had 3 phases. Phase 1 was a 6-month weight loss program. In Phase 2, those who lost ≥4 kg were randomized to a 30-month maintenance trial. In Phase 3, PC participants (n = 196, three sites) were re-randomized to no further intervention (PC-Control) or continued intervention (PC-Active) for 30 more months; 218 SD participants were also followed.

Results: During Phase 3, weight increased 1.0 kg in PC-Active and 0.5 kg in PC-Control (mean difference 0.6 kg; 95% CI:-1.4 to 2.7; P = 0.54). Mean weight change over the entire study was -3.2 kg in those originally assigned to PC (PC-Combined) and -1.6 kg in SD (mean difference -1.6 kg; 95% CI:-3.0 to -0.1; P = 0.04).

Conclusions: After 30 months of the PC maintenance intervention, continuation for another 30 months provided no additional benefit. However, across the entire study, weight loss was slightly greater in those originally assigned to PC.

Trial registration: ClinicalTrials.gov NCT00054925.

© 2016 The Obesity Society.

Figures

Figure 1

Design of the Weight Loss Maintenance Trial. SD = self-directed; PC = personal contact; IT = interactive technology. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]

Figure 2

Participant flow during Phases 1, 2, and 3 of the Weight Loss Maintenance Trial at the Baltimore, Baton Rouge, and Durham clinical centers.

Figure 3

(a) Adjusted mean (95% CI) weight change from study entry for the 196 participants in the Weight Loss Maintenance Trial who were assigned to the personal contact (PC) intervention during Phase 2 and who subsequently were randomized to receive continued PC intervention (PC-Active) or no further intervention (PC-Control) during the 30-month Phase 3 period. (b) Adjusted mean (95% CI) weight change from entry for all 491 participants originally randomized to the self-directed (SD) and PC conditions. Data are limited to participants from the Baltimore, Baton Rouge, and Durham clinical centers and do not include the four individuals who subsequently died. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]