Diet-based avoidance implications in rats in the conditional association with aversive stimuli

The growing number of overweight and obese individuals is a serious medical and social problem. On the one side, calories are important for our survival and well-being, providing structural blocks and energy sources to the organism; hence, on the other side, tasty calories can be easily overused and exceed the body's energy needs, leading to rapid weight gain and obesity. For energy homeostasis, a balance has to be established between consumed calories and energy expenditure. We designed an experiment to establish a conditioned association between calorie-rich food and aversive stimulus to test if the food choice will be affected. Three months prior to the experiments, we subdivided animals into calorie-rich and low-calorie groups. In the first part of the experiment as the aversive stimulus, an electric shock was applied on the basis of the learned helplessness chamber with minor alterations. Along with calorie-rich food, we aimed to establish an aversive association with the color of the chamber. For the second part of the experiment, we tested the food and color choice of shock-exposed and shock-free animals on a calorie-rich and low-calorie diet. There are diet-based differences in food-associated avoidance behaviors and similar behaviors in color-associated avoidance. Animals prefer familiar food, hence there are differences in the amount of consumption. Animals on calorie-rich diets are more prone to depressive-like states. Acquiring rewards and avoiding aversive stimuli have a vital role in shaping responses to environmental factors such as danger, and novelty, as well as for adaptation, emotional status, and cognition.