Insulin Resistance and Reward Signaling in Obesity

Obesity is a common problem in the Veteran population as at least 1 in 3 Veterans have obesity. When people with obesity taste food they have less response in areas of the brain that sense pleasure (reward). Decreased pleasure response to food predicts future weight gain. It is not known if this poor brain response is reversible or why obese people's brains respond this way. Insulin in the brain regulates the brain's sensing of pleasure. As people gain weight the function of insulin becomes impaired. The investigators will study if impaired function of insulin is related to a lessened brain response to food and if this brain response predicts voluntary intake of food and response to a low-calorie diet. The investigators will also study if improving the function of insulin with weight loss improves the brain response. These studies will improve the understanding as to why weight loss is difficult and inform us if improving insulin signaling is a potential way to treat obesity.