Obesity Abstracts

Background: Hypo-activation of the dorsolateral prefrontal cortex (DLPFC), evident in adults with obesity, is associated with increased reward response to high-calorie foods. Transcranial direct current stimulation (tDCS) over the DLPFC has been shown to reduce food cravings and consumption, attenuating reward response. Eating behaviour traits may be relevant to tDCS outcomes; previous research has largely failed to consider such effects. The present study examined the effects of tDCS on food reward and craving using a healthy weight control, and is the first to explore implicit and explicit appeal bias for sweet and high-fat foods following tDCS.

Methods: Twenty-one participants (11 female, 24±7 years, 22.8±2.3 kg·m⁻²) completed two sessions involving randomised and counterbalanced anodal or sham tDCS over the right DLPFC, at 2 milliampere for 20 minutes. Eating behaviour traits were assessed using: Food Craving Questionnaire-Trait, Three Factor Eating Questionnaire, Control of Eating Questionnaire. During sessions, subjective appetite sensations were measured using 100 mm visual analogue scales. Food reward was assessed using the Leeds Food Preference Questionnaire, in-the-moment craving using the Food Craving Questionnaire-State, and food choice motives using the Food Choice Questionnaire. Pearson’s correlations were used to determine test-retest reliability of baseline data. Data were compared using analysis of variance (ANOVA) to 0.05 alpha level.

Results: Participants displayed ‘healthy’ eating behaviour with low trait craving, good craving control, and low Uncontrolled Eating and Emotional Eating scores. Test-retest analysis indicated moderate-to-good reliability of baseline measures (r=0.536–0.955, P<0.020), except for desire to eat (r=0.382, P=0.088). Stimulation had no significant effect on each variable, with fat and taste appeal bias remaining stable (mean difference from baseline 2.20, SD 8.38 AU). Throughout, between-participant variation was large.

Conclusion: Healthy participants with no apparent eating behaviour trait susceptibilities to overconsume did not respond to stimulation, suggesting increasing DLPFC activity using tDCS does not change food reward response in healthy controls. Treatment effects may be seen in individuals with ‘problematic’ eating behaviour traits (e.g. high trait craving or binge-eating) who are overweight/obese or at risk of weight gain.

Keywords: Brain stimulation, dorsolateral prefrontal cortex, food reward, food craving

Disclosure: The authors declare no conflict of interest.