Fiber Intake, Dietary Energy Density, and Adherence to Diet Assignment are Positively Associated with Weight‐Loss in Free‐Living Adults Consuming Calorie‐Restricted Diets at 6‐Month Follow‐Up: The POUNDS LOST Study

Abstract

Low‐fat diets were previously thought to be a key to achieving healthy weight; but higher fat and protein diets have also been shown to produce weight loss. The POUNDS LOST study was a randomized clinical trial which examined the effects of four calorie‐restricted diets of varying macronutrient composition on weight loss in free‐living adults with obesity. Participants were randomized to receive one of four diets: 1) 20% fat, 15% protein; 2)20% fat, 25% protein; 3) 40% fat, 15% protein; and 4) 40% fat, 25% protein. The objective of this analysis was to identify possible predictors of weight loss after 6 months including: diet type, dietary adherence, demographics, and dietary behaviors. Dietary adherence was defined as consuming within ± 5% of the target macronutrient composition for fat and protein. Three hundred forty‐five participants (54.8% female; 86.5% Caucasian, 12.4% African American, and 1.1% other) who provided baseline and 6‐month follow‐up data were included in the analyses. Stepwise regression and cross‐validation techniques were used to model weight loss as a function of all possible predictors. Average Squared Error was the primary model fit criterion by which the final model was selected; the following model fit criteria were also in agreement with the selection of the final model: Akaike information criterion (AIC), Corrected AIC, and Adjusted R‐Square. The following variables were retained: Age, dietary adherence, energy density change, and fiber intake. Mean weight loss was −8.4 ± 5.0 kg and did not vary across diet‐type. Energy density change was positively associated with weight change while age, dietary adherence, and fiber intake were inversely associated with weight change. Fiber intake was the strongest predictor; on average, a 10g increase in fiber intake was associated with 2.2kg decrease in body weight. These findings provide evidence for modifying dietary components like fiber and energy density to positively influence weight loss.Support or Funding InformationFunded by NIH‐NHLBI. ClinicalTrials.gov number, NCT00072995.