Sex differences in hedonic feeding influenced by the gut microbiome

Eating disorders and severe obesity exhibit sex differences. The prevalence of severe obesity (body mass index ≥ 40) for adult women in the United States was 12.1% in 2023 compared to 6.7% for adult men. Among the proposed causes of obesity is increased hedonic feeding: food intake driven by pleasure and palatability rather than physiological hunger. Emerging evidence shows that the gut microbiome impacts feeding behavior and studies have shown that individuals with obesity and eating disorders exhibit an altered gut microbiome. Here, we used a novel, single-session behavioral economics (BE) approach to evaluate hedonic feeding in male and female Sprague-Dawley rats for a high-fat palatable (HFP) reward pellet before and after antibiotic administration. We determined a higher demand at null cost, a prediction of consumption at null effort extrapolated from the animals’ consumption at low price, for the HFP reward pellet for females compared to males, as we have observed previously. Importantly, we investigated a role of the gut microbiome for sex differences in hedonic feeding; we administered an antibiotic cocktail in between measuring BE values to severely deplete the gut microbiome. We determined that administration of antibiotics to deplete the microbiome normalized demand at null cost between males and females.