Effects of a weight loss maintenance intervention on eating behaviours and theoretical mediators: NULevel RCT

Abstract

Background: After successful weight loss, most individuals regain weight. The NULevel trial evaluates the effectiveness of a scalable, technology-assisted, behavioural intervention for weight loss maintenance in obese adults after initial weight loss. Methods: This 12-month single-centre, two-armed parallel group, randomised controlled superiority trial recruited 288 previously obese adults after recent weight loss of ≥5 %, with a 1:1 allocation to intervention or control arm. Primary outcome was weight change from baseline to 12 months. Here, changes in secondary outcomes, behavioural and psychological measures from baseline to 6 months were analysed using ANCOVAs with allocation as between-subject factor controlled for baseline measures following intention-to-treat principles. Results: 144 participants each were allocated to control and intervention arm, 117 (81%) completed 6 months assessment in each arm. There were no significant differences between arms in social support, ego depletion, dietary restraint (Three Factor Eating Questionnaire; TFEQ), self-efficacy for weight loss maintenance or habits, self-efficacy and action planning for physical activity. Participants in the intervention arm reported lower levels of uncontrolled eating (p=.019) and emotional eating (p=.022) from the TFEQ, stronger habits for healthy eating (p = .019) and for self-weighing (p<.001), and higher levels of satisfaction with outcomes of weight loss (p = .008), coping planning for physical activity (p=.044), and action planning (p=.001) and coping planning (p=.002) for healthy eating compared to controls. Discussion: Results support some but not all effects of process measures hypothesised in the logic model. Results will be discussed in relation to the main outcomes of the trial.