High-sugar/high-fat diet modulates the effects of chronic stress in cariocas high- and low-conditioned freezing rats

Abstract

Stress and eating disorders are closely related and are a topic of major concern due to their burden on human health. Engaging in unhealthy eating habits may come as a result of stress, and it often serves to alleviate the symptoms of anxiety or as a distraction from the stressor itself or self-awareness. However, it can also lead to negative feelings of a person's body figure, guilty, or shame. As diverse as these consequences are in humans, so are the effects of the combined administration of stress and hypercaloric food in animals’ models. In this study, we assessed the influence of individual innate behavioral predisposition on the effects of chronic unpredictable mild stress and the dietary supplementation with high-sugar/high-fat food. These conditions were applied to male Carioca low- and high-conditioned freezing (CLF and CHF) rats for 21 days. Behavioral results show that the hypercaloric supplement had a protective effect over the alterations caused by the stress. Notably, it was more strongly observed in CHF rather than CLF animals. As the chronic stress led to an impaired behavior in the contextual fear conditioning and the forced swimming tests in the CLF line, animals fed with the HSHF pellet scored responses similar to their untreated control. On CHF rats, these effects also were seen to a broader extent on the open field test, where the locomotor behavior was also increased. No major effects of the diet were seen in the unstressed groups. Overall, our results show that the influences of both chronic stress and hypercaloric feeding depend on innate differences in fear response traits of male Carioca rats.