Diet, weight loss, and cardiovascular disease prevention

Body weight, like cholesterol and blood pressure, are continuous variables. Overweight results when energy intake as food exceeds energy expenditure from exercise for a considerable period of time. When body weight becomes sufficiently high, it poses a risk to cardiovascular and metabolic health. The types of treatments considered by the physician and discussed with a patient should be based on this risk-benefit assessment. The body mass is the basic measurement for this assessment, and should be part of the “vital signs” when a patient is first evaluated by the medical staff. When the body mass index (BMI) is below 25 kg/m2, there is little risk from the body weight, but because obesity is a “stigmatized” condition, many patients, particularly women, desire to lose weight even within the normal range. For this purpose, a high-quality diet like the Dietary Approaches to Stopping Hypertension (DASH) diet at a reduced-calorie intake would be our recommendation. When the BMI is above 25 kg/m2, patients deserve dietary advice, but in addition to a reduced-calorie DASH-like diet, this is a place to consider using “portion-control” strategies, such as the nutrition labels that manufacturers provide on canned and frozen foods to guide patients in reducing calorie intake. In overweight individuals at high risk (ie, those with a BMI above 30 kg/m2 or impaired glucose tolerance, hypertension, or the metabolic syndrome), the use of orlistat or sibutramine along with diet, exercise, lifestyle changes, and portion control should be considered. When the BMI is above 35 kg/m2, bariatric surgery should also be discussed as an option for the "at-risk" individual. Evidence reviewed here shows that modest weight losses of 5% to 10% can reduce the risk of conversion from impaired glucose tolerance to diabetes and can maintain lower blood pressure over extended periods. All of the approaches described above can produce weight losses of this magnitude.