"Obesity affects the population worldwide. A hypercaloric diet associated with a sedentary life, stress, and genetic background, triggers various metabolic disorders, such as metabolic syndrome, diabetes mellitus, cancer, cardiovascular diseases, non-alcoholic fatty liver disease, and cognitive impairment. A healthy diet correlated with physical activity, not smoking, and moderate alcohol consumption reduces the risk of developing metabolic diseases. The Mediterranean diet contains antioxidants, fiber, polyunsaturated fats, and compounds with anti-inflammatory, anti-oxidant, anti-cancer, and anti-obesity properties. In a wide variety of species including humans, the reduction of calories between 20-40% significantly improves health, increaseslongevity, and delaysthe development of various pathologies. The main aim of this review is to present the comparative effects of the Mediterranean diet versus the hypercaloric diet on insulin sensitivity. "