Modulating eating behaviour with transcranial direct current stimulation (tDCS): a systematic literature review on the impact of eating behaviour traits

Transcranial direct current stimulation (tDCS) is becoming an increasingly popular technique for altering eating behaviours. Recent research suggests a possible eating behaviour trait-dependent effect of tDCS. However, studies recruit participant populations with heterogeneous trait characteristics, including “healthy” individuals who do not present with eating behaviour traits suggesting susceptibility to overconsumption. The present review considers the effects of tDCS across eating-related measures, and explores whether a trait-dependent effect is evident across the literature. A literature search identified 28 articles using sham-controlled tDCS to modify eating-related measures. Random effects meta-analyses were performed, with subgroup analyses to identify differences between “healthy” and trait groups. Trivial overall effects (g = -0.12 to 0.09) of active versus sham tDCS were found. Subgroup analyses showed a more consistent effect for trait groups, with small and moderate effect size (g = -1.03 to 0.60), suggesting tDCS is dependent on participants’ eating behaviour traits. Larger effect sizes were found for those displaying traits associated with study outcomes (e.g. heightened food cravings). “Healthy” individuals appear to be unresponsive to stimulation. Based on this meta-data, future work should recruit those with eating behaviour trait susceptibilities to overconsumption, focussing on those who present with traits associated with the outcome of interest.