Diet and Physical Activity in the Prevention of Obesity

Numerous epidemiologic and clinical studies have examined the role of dietary factors in the development of obesity. Cumulative evidence indicates that there is no “magic bullet” for weight control. Rather, many individual dietary factors each exert a modest effect on body weight, and over time cumulative effects of small changes in daily energy balance lead to weight gain and obesity. On the one hand, there is some evidence that higher consumption of whole grains, fruits, and vegetables is beneficial for weight control. On the other hand, higher intake of sugar-sweetened beverages is associated with both weight gain and type 2 diabetes risk. Emerging evidence suggests potential weight control benefits by lowering refined carbohydrates and glycemic loads, but prospective data are limited. Epidemiologic studies have provided strong evidence that sedentary such as prolonged TV watching is an important risk factor for obesity and type 2 diabetes, whereas increasing physical activity including brisk walking is associated with weight maintenance and a lower risk of obesity and type 2 diabetes. Given the obesogenic environment in which we live, characterized by the abundance of energy dense, processed and highly convenient foods, and sedentary lifestyle, it is critical to change our nutrition and physical activity environment and social norms. Otherwise, the effects of any kind of weight loss or maintenance diets are difficult to sustain.