The epidemic of obesity in the United States has spread at such an alarming rate over the last decade that most adults are now overweight or obese. The association of obesity with mortality and a broad range of significant medical comorbidities portends staggering healthcare, social, and economic costs. Treatment should be directed at the fundamental imbalance between energy intake and expenditure in the context of an environment that increasingly favors excess weight. Therefore, treatment plans need to address the multiple factors that contribute to obesity, including high-calorie diets, sedentary lifestyles, and weight-sustaining behaviors. Primary care physicians would do well to focus on helping willing patients make small changes motivated more by health promotion and fitness than by weight loss.