Williamson, Donald A.Anton, Stephen D.Han, HongmeiChampagne, Catherine M.Allen, RayLeBlanc, EricRyan, Donna H.McManus, KatherineLaranjo, NancyCarey, VincentLoria, Catherine M.Bray, George A.Sacks, Frank2017-02-072009Williamson, Donald A., Stephen D. Anton, Hongmei Han, Catherine M. Champagne, Ray Allen, Eric LeBlanc, Donna H. Ryan, et al. 2009. “Adherence Is a Multi-Dimensional Construct in the POUNDS LOST Trial.” Journal of Behavioral Medicine 33 (1) (October 25): 35–46. doi:10.1007/s10865-009-9230-7.0160-7715http://nrs.harvard.edu/urn-3:HUL.InstRepos:30203407Research on the conceptualization of adherence to treatment has not addressed a key question: Is adherence best defined as being a uni-dimensional or multi-dimensional behavioral construct? The primary aim of this study was to test which of these conceptual models best described adherence to a weight management program. This ancillary study was conducted as a part of the POUNDS LOST trial that tested the efficacy of four dietary macronutrient compositions for promoting weight loss. A sample of 811 overweight/obese adults was recruited across two clinical sites, and each participant was randomly assigned to one of four macronutrient prescriptions: (1) Low fat (20% of energy), average protein (15% of energy); (2) High fat (40%), average protein (15%); (3) Low fat (20%), high protein (25%); (4) High fat (40%), high protein (25%). Throughout the first 6 months of the study, a computer tracking system collected data on eight indicators of adherence. Computer tracking data from the initial 6 months of the intervention were analyzed using exploratory and confirmatory analyses. Two factors (accounting for 66% of the variance) were identified and confirmed: (1) behavioral adherence and (2) dietary adherence. Behavioral adherence did not differ across the four interventions, but prescription of a high fat diet (vs. a low fat diet) was found to be associated with higher levels of dietary adherence. The findings of this study indicated that adherence to a weight management program was best conceptualized as being multi-dimensional, with two dimensions: behavioral and dietary adherence.en-USJournal Article2017-02-0710.1007/s10865-009-9230-7