Psychological well-being factors and the likelihood of overweight and obesity reversal at population level: Two cohort studies of UK adults

Background: Poorer psychological well-being is associated with obesity and has been presumed to be one reason why significant long-term weight loss is difficult. However, there is limited evidence on whether better psychological well-being is prospectively associated with likelihood of transition from overweight and obesity into normal weight among the general population. We examined the role of psychological well-being related factors in overweight and obesity reversal.Methods: We used data from two comparable British cohort studies, the National Child and Development Study (NCDS) and the British Cohort Study (BCS) to examine the prospective associations between psychological well-being related factors (depressive symptoms, life satisfaction, self-efficacy) and overweight and obesity reversal (vs. persistence) and change in body mass index (BMI), controlling for sociodemographic covariates. We analysed reversal between multiple baseline and follow-ups (6-7 years of follow-up on average) separately in each cohort (n = 8,513 and 11,113 observations for NCDS and BCS, respectively) using panel data analysis, and then replicated the analysis in smaller analytical sample sizes with longer follow-up (16-17 years of follow-up). To examine overall effect sizes and maximise statistical power, we also conducted pooled cohort analyses. Results: A proportion (8-9%) of participants with overweight and obesity (BMI ≥ 25) at baseline transitioned into normal weight (BMI 18.5 - < 25) by follow-ups. In both NCDS and BCS, there was no evidence of psychological well-being related factors associated with overweight and obesity reversal or continuous BMI change in both short-term and long-term follow-ups. Findings were consistent in the pooled cohort analyses. However, some sociodemographic characteristics were associated with overweight and obesity reversal, such as being younger than age 42 and female (vs. male). In additional pooled analysis limited to participants with overweight at baseline, findings were consistent with no associations between psychological well-being related factors and transition into normal weight.Conclusion: There was no convincing evidence that psychological well-being related factors were prospectively associated with reversal of overweight and obesity into normal weight or smaller degrees of weight loss. Better psychological well-being may not be associated with likelihood of weight loss once obesity is developed in adulthood.