Lifestyle modifications should be recommended for every patient dealing with overweight or obesity. Behavior modification is the cornerstone of management. Motivational interviewing, goal setting, and self-monitoring are three techniques with proven efficacy for weight reduction. Because an energy deficit is required to promote weight loss, goal setting should be focused on achieving an overall caloric reduction. No single diet has proven to be superior to others overall in terms of weight loss outcomes. However, a low-carbohydrate (ie, ketogenic) diet has been shown to reduce insulin resistance in patients with diabetes and may be considered for this subgroup of patients. There continue to be conflicting views regarding the superiority of low glycemic index foods for weight loss. Exercise alone has not been shown to produce substantial weight loss, but it is helpful during the weight loss phase to preserve lean muscle mass, and it has a role in weight maintenance. Though sleep deprivation has been implicated in weight gain, the effect of improving sleep quality/duration on reducing excess weight has yet to be studied adequately.