Americans are crazy about diets and dieting, yet obesity is reaching epidemic proportions. Some swear by Pritikin, some by Ormish, others by South Beach, Atkins, and an alphabet soup of eating plans. At the same time, the average American is gaining so much weight that airlines have had to rework their formulas for cargo and fuel loading to allow for heavier passengers.
    "For my entire career, I have been trying to help people lose weight," said Corey Evans, MD, director of medical education for St. Anthony's Hospital in St. Petersburg, Fla. "It has been a discouraging process. We are having a tidal wave of obesity. Right behind it is a tidal wave of diabetes that is swamping primary care providers."
    Diabetes, hypertension, cardiovascular disease, and the other sequelae of obesity that physicians are accustomed to seeing in adults are appearing in teenagers and preteens. A recent study of preparticipation medical exams for would-be athletes in high school and middle school found that 20% are pre-hypertensive, noted Kevin Burroughs, MD, assistant professor of family medicine at the University of North Carolina at Concord. Seven percent showed blood pressure that puts them in the hypertensive range.
    What neither children nor their parents realize is that early obesity has consequences. Thirty-year olds are being admitted for myocardial infarct and CABG, said Jeffrey Zlotnick, MD, assistant clinical professor of family medicine and primary care sports medicine at the Robert Wood Johnson Medical School, Piscataway, NJ. Their coronary disease is a direct result of childhood obesity.
    "These kids aren't really eating that much more," he told the American Academy of Family Physicians Scientific Assembly. "They are just moving a lot less."
    Exercise is a key component to successful weight loss. Data from the National Weight Loss Registry show that while the typical registrant lost 66 pounds for an average duration of five years, fewer than 10% used diet alone to achieve their loss. They used diet plus exercise.
    Exercise on its own is also insufficient—less than 1% of registrants lost weight with exercise alone. The vast majority combined exercise with a low fat, low caloric density diet. The average fat content was 23% but a third of registrants ate less than 20% fat. Dr. Evans noted that the American Heart Association, by comparison, recommends a diet with 30% fat or less.
    A 2000 analysis of eight popular diets (including ADA, Atkins, Pritikin, Sugar Busters, and Zone) showed that individuals derive the greatest health benefit from diets low in saturated fat and high in carbohydrate and fiber. This combination increases sensitivity to insulin and lowers risk for coronary artery disease.
    Low carb diets are higher in saturated fats and cholesterol. Long-term use would boost cholesterol levels as well as risk for CAD.
    Sugar-restricted diets would lower serum cholesterol and CAD risk.
    High fat diets may promote short-term weight loss but increase the risks for progression of CAD over the longer term.
    Physicians should help patients choose a diet that reflects the patient's own food preferences and psychological strengths. Group programs such as Weight Watchers and individual plans can both be successful. The more comfortable patients are with the program, the more likely they are to stick with it.
    One of the most useful tools in weight management is an eating diary. Few people have an accurate idea of just how many calories they consume daily.
    "Simply keeping track of what they eat and counting up the calories can be a real eye opener," Dr. Evans said. "Keeping an eating log is one of the most important steps in losing weight and keeping it off."
    The final element, he said, is helping patients understand calorie density. They can eat as much as they want as long as the foods are not dense in calories. As long as the average calorie density is 400 calories per pound or less, the patient will probably lose weight.