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OVERWEIGHT - HOW DANGEROUS IS IT TO YOUR HEALTH?

By Donald B. Louria, M.D

(May 2001)

The United States is in the grip of an epidemic of overweight - and it appears to be getting progressively worse. About one-half of American adults are overweight; that figure breaks down into about 30 percent who are moderately overweight (up to 20 percent above ideal weight) and about 20 percent who are at least 20 percent above ideal weight and are classified as obese.

In the past, the definition of overweight and obese were based on the relationship of height to weight (CLICK HERE FOR HEIGHT-WEIGHT TABLES). In recent years, that definition has been replaced by the BMI - the body mass index. That is determined by converting height and weight from feet, inches, and pounds to the metric system (height in meters, weight in kilograms). Then the weight is divided by the height squared to get a number that ranges from less than 19 (very underweight) to over 40 (markedly obese). Ideal in regard to lowest likelihood of death was found to be between 22 and 25 for white men and women.

Those with BMI values of 25 to 30 are considered overweight; a BMI of 30 to 35 is classified as mildly or moderately obese; 35 to 40 is moderately to severely obese; and above 40 is extreme obesity (CLICK HERE TO CALCULATE YOUR BMI).

There are problems in interpreting the BMI. Older height for weight definitions took into account bone and muscle structure and the effects of growing older. In contrast, body mass index ignores body type and bone size; consequently it may call people with big bones and muscles overweight when they are not. And, it does not allow for any weight gain during middle age and later in life.

A big problem with being overweight, even by only a modest amount, is that at least 50 percent of those who are moderately overweight (less than 20 percent over ideal or body mass index of between 25 and 30) develop risk factors for coronary heart disease, stroke, or diabetes - an elevated blood cholesterol level, elevated blood pressure, or high blood sugar. Such abnormalities should be corrected, preferably by weight loss. For those who gain a moderate amount of weight and develop no risk factors for coronary heart disease, stroke, or diabetes, the weight gain is probably primarily a cosmetic problem.

Another major problem for those less than 20 percent overweight (or body mass index 25 to 30) is that it is very easy to keep gaining and get to the category of more than 20 percent over ideal weight (body mass index more than 30). When that happens, you are at greater risk of death mainly from heart disease and strokes from overweight itself; additionally, it is even more likely the weight gain will be accompanied by potentially dangerous elevations in cholesterol, blood pressure, and glucose levels.

Weight gain in the abdomen (central obesity) is the more dangerous component of overweight. Some people seem to gain weight all over; for others, the extra pounds seem to settle in the lower abdomen producing a big gut; that may be more dangerous for risk of both heart attacks and strokes.

The evidence suggests that the health consequences of overweight are greatest for those ages 30 to 64. For those ages 65 to 74 years, overweight produces considerably less risk of death and for those over 75, only the top body mass index categories (over 40) show even a modestly increased risk. Although the dangers of overweight are less for those over 65 years of age, you still have to check overweight-related risk factors for heart disease and stroke (cholesterol level and blood pressure). If these are elevated, you still should take action to normalize them by weight loss or, if necessary, by medication.

But, after age 65, a cholesterol level of up to 220 milligrams and, after age 75, a cholesterol level up to 240 milligrams should be considered not ideal, but not a major concern unless your cholesterol:high-density lipoprotein cholesterol (HDL-good cholesterol) ratio is 6 or more. Even then (or if you just do not like cholesterol levels that high), the approach should be dietary modification (see Archives, Cholesterol, "So you want to lower your cholesterol level without taking drugs?), plus, if possible, modest weight loss. After age 65, cholesterol-lowering medication (if used at all) should ordinarily be reserved for those with cholesterol levels over 220 (ages 65 to 74) or over 240 (75 and above), or for those with cholesterol:HDL ratios of 6 or more who do not respond to dietary changes.

With each additional five years after age 65, overweight, other than extreme overweight, becomes increasingly a cosmetic, not a medical problem. It makes no sense to overreact at that age. It is ridiculous to put older people over age 80 (when often one of the main pleasures of life is eating) on rigid diets just because they are moderately overweight or have a high cholesterol level.

If you are more than 20 percent above ideal weight, if your body mass index is 30 or above, if your weight gain is concentrated in your belly, you are at somewhat increased risk of death or heart attack just because of the weight gain and you had better do something about it. The higher the body mass index figure, the more above 30, the greater the urgency to take action. Once you exceed a body mass index of 30, the health dangers of heart attack or stroke are compounded by smoking. So, if you are 20 percent over ideal weight (or body mass index over 30) and you are a smoker, you ought to stop.

Fortunately, the evidence shows that moderate weight loss, especially for those who are less than 20 percent overweight, can be very effective in normalizing cholesterol, blood pressure, and glucose. Often all that is needed is a 5 percent weight loss - that is, 6 pounds for a 120 pound person, 7-1/2 pounds for somebody weighing 150 pounds, 10 pounds for a 200 pound person, and 12-1/2 pounds for a person weighing 250 pounds. These are readily achievable goals. In some cases, a 5 percent weight loss will not be effective and a 10 percent, or even greater, loss will be required.

For most people with that kind of needed weight loss (5 percent, even 10 percent) exercise and diet are all that is needed; but, for those who need help in achieving the goals, good prescription medications are available. For those who are frankly obese, moderate weight loss is less likely to normalize cholesterol levels and blood pressure, and is still likely to leave the individual enough overweight to be at somewhat increased risk of death from the overweight itself.

There is a downside in becoming overly focused on the potential dangers of modest overweight (less than 20 percent above the ideal). The concern is that too many people will become involved with fads, or even possibly harmful diets, promoted by the ever-present entrepreneurs. Additionally, too many people, over-interpreting the dangers of moderate overweight, will risk the adverse effects of unproved drugs, dietary supplements, herbs, etc in the hope of losing weight. The best approach to moderate weight gain is still to check your cholesterol and blood pressure (also your blood sugar) and, if any one is abnormal, lose weight by a sensible diet, a reasonable amounts of exercise, and, if necessary, fully_documented medications taken under a physician’s supervision.