Psychological factor (PF) changes during a randomized trial of legume consumption during weight loss

Abstract

Weight loss attempts often fail. Legumes are high in satiety factors and may aid weight loss, but PFs may also influence weight loss and vice‐versa. In a 6wk study, subjects (n= 42; BMI 25–35 kg/m2) were randomized to consume LOW (1T), medium (MED; 0.5c) or HIGH (1.8–2.7c) legumes 6d/wk while reducing energy intake (EI) by 30%. ~50% of the target EI was provided and the remainder was self‐selected. All groups lost weight (2.7±2.3kg; p=0.023), with MED losing more than LOW (p=0.032) but not HIGH (p=0.12). PFs changed over time in all groups: dietary disinhibition, its two subscales (situational susceptibility, uncontrolled eating) and hunger decreased, whereas self‐efficacy, dietary restraint and several restraint subscales (strategic dieting, avoiding fattening foods (AFF), flexible control, rigorous control) increased (p≤0.005). There were significant group by time interaction effects on external hunger (p=0.046) and habitual disinhibition (p=0.003); external hunger increased more in MED compared to LOW (p=0.015) and habitual disinhibition increased more in MED compared to HIGH (p=0.063). Predictors of greater weight loss were a more mindful eating style at baseline (p=0.023) and a decrease in AFF score (p=0.051), independent of baseline AFF, baseline weight and legume treatment. These data suggest that PFs may have helped explain differences in weight loss among legume groups. [Funding: Pulse Canada PIP]