(P15-013-24) Early Weight Loss and Other Predictors of Clinically Significant Weight Loss on Two Commercial Weight Loss Programs

Objectives: Individual weight loss response to commercial programs, and lifestyle interventions in general, is highly variable. Therefore, identifying predictors of meaningful weight loss in adults with excess body weight is critical for ensuring positive outcomes. This secondary analysis assessed potential predictors of achieving ≥5% or ≥10% weight loss over a 16-week period among adults with overweight or obesity in a clinical trial evaluating two commercial weight loss programs.

Methods: Data from 124 participants [45.7 (13.1) years, 20.2% male, BMI 34.4 (3.4) kg/m²] randomly assigned to the OPTAVIA program [n=60, coach-guided 800-1000 calorie partial meal replacement plan (PMR) with scheduled nutrition/ behavioral support calls plus ad hoc support] or the Medifast program [n=64, self-guided 1000-1200 calorie PMR with ad hoc nutrition/ behavioral support only] in a previously published trial (Arterburn, et al., Obesity Science and Practice, 2018) were assessed. Participants were stratified by % weight loss at 2, 4 and 16 weeks. Univariate and multivariate logistic regression analyses were used to assess weight loss thresholds and potential demographic, anthropometric, behavioral and lifestyle predictors of ≥5% or ≥10% weight loss.

Results: In multivariate analyses, age, education, ≥1% weight loss by week 2, ≥2% weight loss by week 4, number of support contacts, and dietary adherence through week 4 were significant (P < 0.05), positive predictors of achieving ≥5% weight loss. Most notably, participants with ≥2% weight loss by week 4 had 24.6 (95% CI: 2.49, 243) times greater odds of losing ≥5% by week 16. For the prediction model of ≥10% weight loss at 16 weeks, positive predictors included age, assignment to the OPTAVIA program, ≥3% weight loss by week 4 and dietary adherence through week 4 (P < 0.05). Specifically, participants with ≥3% weight loss by week 4 had 19.4 (95% CI: 2.02, 186) times greater odds of losing ≥10% by week 16.

Conclusions: While several factors predicted achievement of clinically significant weight loss at 16 weeks, 4-week weight loss was by far the strongest predictor. These results may be useful for early identification of individuals at risk for failing to achieve clinically significant weight loss who may benefit from intensification of counseling to assist in attaining weight loss goals.

Funding Sources: Medifast, Inc.