Reversing the impact of an obesogenic diet on emotion regulation and brain metabolism: A rat model study

The global rise in obesity and poor dietary habits, particularly the consumption of high-fat, high-sucrose (HFS) diets, is a growing public health concern. These diets, especially when consumed during critical developmental periods, such as gestation and early life, are linked to long-term consequences on both physical and mental health. Early exposure to obesogenic diets has been shown to disrupts brain function and increases the risk of anxiety, depression, and additional emotional disorders. However, it has been suggested that dietary changes during early life may reverse these effects. This study investigated whether switching from an HFS diet to a standard diet (SD) after weaning could reverse abnormal emotional responses (o anxiety- and depression-like behavior) and brain energy metabolic capacity in rats.

Male and female Wistar rats were divided into three groups: one on continuous SD, one on an HFS diet from gestation until adulthood, and one that shifted from HFS to SD after weaning. Emotional behavior was assessed using the saccharin preference test, forced swimming test, and elevated zero maze test. Brain metabolism was evaluated by measuring cytochrome c oxidase (CCO) activity in key regions involved in emotion regulation, such as the nucleus accumbens, ventral pallidum, dorsal striatum, and the bed nucleus of stria terminalis.

Adult animals exposed to the HFS diet exhibited increased depression and anxiety-like behaviors, and elevated CCO activity. Notably, sex differences were observed, with males showing more pronounced anxiety- and depression-like behaviors, although both sexes improved after diet switching. These findings suggest that early dietary interventions can mitigate diet-induced emotional and metabolic disturbances, thereby underscoring the importance of nutrition during critical developmental periods.