Attenuation of stress-induced weight loss with a ketogenic diet.

Ketogenic diets (KDs) are high-fat, low-carbohydrate diets that have been used therapeutically for decades, most notably for the treatment of epilepsy and diabetes. Recent data, however, suggest that KD may impart protective effects on mood disorders. The current experiments test the hypothesis that KDs can protect from stress-induced symptoms of mood disorders. To test this, we assessed behavioral and neuroendocrine effects of KD in male and female Long Evans rats. Animals experienced three weeks of chronic mild stress (CMS) while consuming KD or control chow (CH). Body weight and food intake data were recorded daily and behaviors were assayed after three weeks. Plasma beta-hydroxybutyrate (βHB), corticosterone (CORT) and interleukin-1 beta (IL-1β) were measured after behavioral testing, along with hypothalamic corticotropin-releasing hormone (CRH) and neuropeptide Y (NPY) mRNA expression. CMS induced weight loss in the CH groups, however the KD-fed rats were resistant to CMS-induced weight loss. Female rats fed KD were protected from CMS-induced reductions in plasma CORT and hypothalamic NPY expression. Collectively, these data suggest protective potential of KDs against chronic stress, particularly in females.