Lifestyle, diet, and disease: Comparative perspectives on the determinants of chronic health risks

We evolved under high levels of physical activity and energy expenditure, seasonal fluctuations in food availability, and frequent periods of marginal or negative energy balance. Today, we continue to eat about the same amount but exercise less, and the 'imbalance' between energy intake and expenditure causes obesity. Consumption of meat from feedlot animals now causes atherosclerosis; eating wild or grass-fed animals does not. For most of human history, simple carbohydrates were a minor element of our diet; today Americans derive almost 40% of calories from simple sugars and refined grain products. Simple carbohydrates contribute to the rise of type 2 diabetes in the industrialized world. The problems of 'overnutrition' and energy surplus are causing rates of obesity, diabetes, and hypertension to increase more rapidly in the developing than in the industrialized world. Nutritional interventions should promote increased exercise and activity levels as well as dietary modifications.