Does the incorporation of portion-control strategies in a behavioral program improve weight loss in a 1-year randomized controlled trial?

Abstract

Background/ObjectivesControlling food portion sizes can help reduce energy intake, but the effect of different portion-control methods on weight management is not known. In a one-year randomized trial, we tested whether the efficacy of a behavioral weight-loss program was improved by incorporating either of two portion-control strategies instead of standard advice about eating less.Subjects/MethodsThe Portion-Control Strategies Trial included 186 women with obesity (81%) or overweight (19%). Participants were randomly assigned to one of three equally intensive behavioral programs consisting of 19 individual sessions over 12 months. The Standard Advice Group was instructed to eat less food while making healthy choices, the Portion Selection Group was instructed to choose portions based on energy density using tools such as food scales, and the Pre-portioned Foods Group was instructed to structure meals around pre-portioned foods such as single-serving main dishes, for which some vouchers were provided. In an intention-to-treat analysis, a mixed-effects model compared weight loss trajectories across 23 measurements; at Month 12, weight was measured for 151 participants (81%).ResultsThe trajectories showed that the Pre-portioned Foods Group initially lost weight at a greater rate than the other two groups (P=0.021), but subsequently regained weight at a greater rate (P=0.0005). As a result, weight loss did not differ significantly across groups at Month 6 (mean±SE 5.2±0.4 kg) or Month 12 (4.5±0.5 kg). After one year, measured weight loss averaged 6% of baseline weight. The frequency of using portion-control strategies initially differed across groups, then declined over time and converged at Months 6 and 12.ConclusionsIncorporating instruction on portion-control strategies within a one-year behavioral program did not lead to greater weight loss than standard advice. Using pre-portioned foods enhanced early weight loss, but this was not sustained over time. Long-term maintenance of behavioral strategies to manage portions remains a challenge.

Early predictors of weight loss in a 1‐year behavioural weight‐loss programme

“…Programme attendance is often shown to influence long‐term weight loss, as it did when examined across the year in this trial . However, attendance in the first month did not predict subsequent weight loss, likely due to little variability in the measure.…”

The Weight-Related Eating Questionnaire offers a concise alternative to the Three-Factor Eating Questionnaire for measuring eating behaviors related to weight loss

“…An overview of trial participants and design is presented below. Further details of the trial design and main outcome data are presented elsewhere (Rolls, Roe, James, & Sanchez, 2017). …”

“…In order to support effective interventions, it is important to determine reliable measures of the eating behaviors and attitudes that influence weight change. In this study, two eating behavior questionnaires were administered repeatedly during a one-year weight loss trial (Rolls, Roe, James, & Sanchez, 2017) in order to identify correlates of weight change.…”

The portion size effect and overconsumption – towards downsizing solutions for children and adolescents

“…) or a 12‐month (Rolls et al . ) weight loss trial facilitated early weight loss. However, in the 12‐month trial, portion control strategies did not lead to a greater weight loss than standard advice.…”