Association of Changes in Neural Targets and Dietary Outcomes among Patients with Comorbid Obesity and Depression: Post hoc Analysis of ENGAGE-2 Mechanistic Clinical Trial

Abstract

BackgroundDisruptions in brain circuits that regulate cognition and emotion can hinder dietary change and weight loss among individuals with obesity and depression. ObjectiveThe study aimed to investigate whether changes in brain targets in the cognitive control, negative affect, and positive affect circuits after 2-mo problem-solving therapy (PST) predict changes in dietary outcomes at 2 and 6 mo. MethodsAdults with obesity and depression from an academic health system were randomly assigned to receive PST (7-step problem-solving and behavioral activation strategies) over 2 mo or usual care. Seventy participants (mean age = 45.9 ± 11.6 y; 75.7% women, 55.7% Black, 17.1% Hispanic, 20.0% White; mean BMI = 36.5 ± 5.3 kg/m2; mean Patient Health Questionnaire-9 depression score = 12.7 ± 2.8) completed functional MRI and 24-h food recalls. Ordinary least square regression analyses were performed. ResultsAmong intervention participants, increased left dorsal lateral prefrontal cortex (dLPFC) activity of the cognitive control circuit at 2 mo was associated with increased diet quality (β: 0.20; 95% CI: −0.02, 0.42) and decreased calories (β: −0.19; 95% CI: −0.33, −0.04), fat levels (β: −0.22; 95% CI: −0.39, −0.06), and high-sugar food intake (β: −0.18; 95% CI: −0.37, 0.01) at 6 mo. For the negative affect circuit, increased right dLPFC–amygdala connectivity at 2 mo was associated with increased diet quality (β: 0.32; 95% CI: −0.93, 1.57) and fruit and vegetable intake (β: 0.38; 95% CI: −0.75, 1.50) and decreased calories (β: −0.37; 95% CI: −1.29, 0.54), fat levels (β: −0.37; 95% CI: −1.50, 0.76), sodium concentrations (β: −0.36; 95% CI: −1.32, 0.60), and alcohol intake (β: −0.71; 95% CI: −2.10, 0.68) at 2 but not at 6 mo. The usual care group showed opposing associations. The 95% CIs of all between-group differences did not overlap the null, suggesting a significant treatment effect. ConclusionsAmong adults with obesity and depression who underwent PST compared with those under usual care, improved dLPFC–amygdala regulation of negative affective brain states predicted dietary improvements at 2 mo, whereas improvements in dLPFC-based cognitive control predicted dietary improvements at 6 mo. These findings warrant confirmatory studies.This trial was at clinicaltrials.gov as NCT03841682.