A study from Rutgers University published in The Journal of Neuroscience has found that high-fat food can rapidly alter brain circuits involved in appetite and energy balance. In mice, measurable changes appeared after just 24 hours, and the underlying adaptations differed between males and females.
The researchers focused on glutamatergic excitatory neurons in the lateral hypothalamus, a brain region involved in feeding and energy expenditure. These neurons are associated with reduced food intake and increased metabolic activity. Before exposure to a high-fat diet, neurons in female mice showed greater baseline excitability than those in males, meaning they required less electrical stimulation to fire.
After one day on the diet, the two sexes displayed different forms of synaptic remodeling. In males, the neurons became intrinsically more excitable, but the excitatory inputs that normally activate them weakened. In females, intrinsic excitability did not change, while inhibitory synaptic inputs were reduced, weakening the signals that restrain neuronal activity.
The study also tested the effects of chronically increasing the activity of these neurons during high-fat feeding. In male mice, the intervention limited body-weight gain. In female mice, the same manipulation led to significant weight loss despite continued access to the high-fat diet.
The findings indicate that the brain circuits regulating feeding respond to excess dietary fat through sex-specific mechanisms. The authors suggest that these differences could help explain why the same dietary conditions may produce distinct metabolic responses, while also highlighting the importance of including both sexes in research on obesity and appetite regulation.
The research paper, titled “High-Fat Diet Feeding Rapidly Induces Sex-Specific Neuronal Plasticity in Lateral Hypothalamic Glutamatergic Neurons,” was authored by Yi Lu and Mark A. Rossi.
Sources: Neuroscience News.