Effect of High Caloric Diet on Brain Insulin Sensitivity and Inflammation

Obesity if known to be associated with brain insulin resistance in humans and evidence is rapidly accumulating that brain insulin resistance influences peripheral metabolism, eating behavior and cognition. A reduced insulin response in the brain is found mainly in people with a metabolically unfavorable fat distribution - high visceral fat. Visceral fat produces inflammatory mediators and elevated inflammatory levels are closely linked to insulin resistance. Inflammation of the brain (i.e., neuroinflammation) has been proposed as a possible cause of brain insulin resistance. Interestingly, rodent models of a high calorie diet show that these inflammatory mechanisms occur rapidly in the brain, even prior to weight gain of the animals. Among other things, it has been shown in humans that a short-term increase in calories, especially carbohydrates and fats, reduces insulin sensitivity in the body and increases inflammatory parameters in the blood. Whether a high-calorie diet triggers insulin resistance or inflammation in the human brain is currently unknown. Aim of study: The aim of the study is to investigate the effects of a five-day high calorie diet in healthy young male volunteers on peripheral and brain insulin sensitivity as well as on eating behavior, mood and cognition. Brain insulin sensitivity, peripheral metabolism and different behavioral assessments will be evaluated before, 1 week and 2 weeks after high caloric diet.