The obesity epidemic is best explained by global lifestyle alterations favoring weight gain in a susceptible population. The consumption of calorically dense foods, increased portion sizes, and a decrease in workplace and leisure physical activity most likely accounts for the increase in overweight and obesity worldwide. The cornerstone of overweight and obesity therapy is dietary intervention, but unfortunately most patients eventually regain the weight lost through diet alone. The search for a macronutrient composition that may enhance and help maintain weight loss has brought an abundance of fad diets into the lay literature. According to the available data, weight loss and maintenance of weight loss are dictated by total caloric intake, and not by macronutrient composition. There is epidemiologic data linking sugar-sweetened beverages to adult and childhood obesity, and an inverse relationship between dairy intake and overweight and obesity has also been observed. More research is needed to elucidate mechanisms explaining these relationships. Further research should focus on permanent lifestyle changes that may reverse this growing epidemic. This review will focus on current practices for the dietary management of obesity and to promote weight maintenance.