A Commercially Available Portion-Controlled Diet Program Is More Effective for Weight Loss than a Self-Directed Diet: Results from a Randomized Clinical Trial

Abstract

Objective: To examine changes in weight and related outcomes in response to a commercial weight loss program compared to a self-directed diet in adults with overweight or obesity.

Design: Participants were randomly assigned [stratified by body mass index (BMI) and age] to a commercial weight loss program (n = 38) or to a self-directed Dietary Approaches to Stop Hypertension (DASH) diet (n = 40) for a 16-week period. Daily energy intake goals were 1,500 kcal/d for men and 1,200 kcal/d for women, except for the first week of the commercial program (1,000 kcal/d). This study was registered at http://ClinicalTrials.gov (NCT03017443).

Participants: Primarily Caucasian (71%) women (n = 61) and men (n = 17) from the greater metropolitan area of the city of Chicago, IL, USA. with a mean baseline BMI of 34.4 kg/m2, body weight of 95.7 kg, and age of 50.4 years.

Results: Data = mean (95% CI). At week 16, the commercial program group lost significantly more body weight [-5.9 (-7.5, -4.3) kg vs. -1.8 (-2.9, -0.8) kg; or -6.4 vs. -1.8% of initial body weight, respectively], fat mass [-4.4 (-5.7, -3.1) kg vs. -1.2 (-2.1, -0.4) kg] and total body circumference (chest + waist + hip + upper arm + thigh) [-16.9 (-21.5, -12.3) cm vs. -5.8 (-9.0, -2.6) cm] (p < 0.01 for all). Additionally, more participants in the commercial program group lost a clinically meaningful amount of weight, defined as ≥5% of initial body weight, at week 16 (58% vs. 13%, p < 0.001).

Conclusion: The commercial program resulted in greater weight loss and improvements in body composition/anthropometric parameters compared to a self-directed DASH diet over a 16-week period. Some important limitations were that no objective measurements of dietary intake or physical activity were collected to potentially ascertain the independent or combined effects of these components on weight loss (or lack thereof). Additionally, future research is warranted in order to understand the effects of this program, and similar programs, on longer term changes in body weight, in particular weight loss maintenance, as weight regain is common following the cessation of a structured weight loss intervention.

Keywords: body circumference; fat mass; obesity; overweight; pre-portioned foods.

Figures

Figure 1

Change in body weight in men and women with overweight/obesity randomized to a commercial weight loss program or a self-directed Dietary Approaches to Stop Hypertension diet for a 16-week study period. Change from baseline data presented as mean ± 95% CI for the intent-to-treat sample population. Missing data were imputed using the method of last observation carried forward (LOCF). Two participants randomized to the self-directed diet discontinued the study at the baseline visit prior to beginning the assigned dietary intervention on the following day, so no LOCF imputation was applied for these individuals. Repeated measures analysis of covariance was used to assess differences between groups. Initial models contained terms for intervention, sex, stratification factors (body mass index and age categories), and phase of menstrual cycle at start of intervention (follicular, luteal, or N/A), with baseline measures as covariates. Models were reduced using a backward selection method until only significant terms and/or intervention and baseline measure remained in the model.