In this paper I discuss overweight and obesity and their repercussions on health deficit accumulation and longevity in a life cycle model. Individual decisions are conceptualized as the partial control of impulsive desires of a short-run self (the limbic system) by a rationally forward-looking long-run self (the prefrontal cortex). The short-run self-strives for immediate gratification through consumption of food and other goods. The long-run self reflects the consequences of eating behavior on weight gain and health, exercises to lose weight, invests money to improve health and saves for health expenditure in old age. Not conceding to short-run desires, however, entails an idiosyncratic utility cost of self-control. The model is calibrated to match food expenditure, exercise, and other choices of an average U.S. American. The results suggest that imperfect self-control reduces average lifetime by up to five years. I use the model to analyze the role of self-control, income, food prices, energy density, and medical progress in explaining obesity and to develop a test on whether obesity is driven by excessive desire for food or lack of self-control.
self-control overweight obesity physical exercise health investments aging longevity