Calorie restriction mitigates metabolic, behavioral and neurochemical effects of cafeteria diet in aged male rats.

Besides metabolic dysfunctions, elderly individuals with obesity are at special risk of developing cognitive decline and psychiatric disturbances. Restricted calorie consumption could be an efficient strategy to improve metabolic function after obesity. However, its effects on anxiety-like behaviors in aged rats submitted to an obesogenic diet are unknown. For this purpose, 42 Wistar rats (18-months old) were divided into four groups: Control (CT), calorie restriction (CR), cafeteria diet (CAF), and CAF+CR (CAF/CR). CT, CR, and CAF groups received the diets for 8 weeks. CAF/CR group was submitted to the CAF menu for 7 weeks and then switched to a standard diet on a CR regimen, receiving 30% lower calories than consumed by the CT, for another 5 weeks. CAF's menu consisted of ultra-processed foods such as cookies, chocolate, sausage, and bologna. Body weight, visceral adiposity, and biochemical blood analysis were evaluated for obesity diagnosis. The profile of gut microbiota was investigated, along with circulating levels of LPS. Neurochemical parameters, such as neurotransmitter levels, were dosed. Anxiety-like behaviors were accessed using open field (OF) and elevated plus maze (EPM) tests. As expected, CR reduced weight gain and improved glucose homeostasis. Gut microbiome disturbance was found in CAF-fed animals accompanied by increased levels of LPS. However, CR after CAF mitigated several harmful responses. The obesogenic diet triggered anxiety-like manifestations in the OF and EPM tests that were not evidenced in the CAF/CR group. These findings indicate that CR can be a promising strategy for the neurological effects of obesity in aged rats.