Finding middle ground on the obesity debate

First, scientists estimated that excess weight and obesity claimed 400,000 lives annually. Now, just a year later, another team of researchers has revised those figures downward by 75% and published the results in the prestigious Journal of the American Medical Assn.

Although extra pounds can shorten your life, new research indicates that a few extra pounds may not always be harmful over the long run.

“I didn’t realize how anxious people have been about weight until my study came out,” said Katherine M. Flegal, an epidemiologist at the National Center for Health Statistics and co-author of the JAMA paper, which drew from five large, federally funded surveys conducted from 1971 to 2002. Flegal and her colleagues found that 112,000 people die in the United States annually from weight-related illnesses.

Those numbers still make obesity a killer, just not as lethal as some other scientists have thought. Consider obesity, Flegal said, as akin to having high blood cholesterol, elevated blood pressure or high blood sugar. “You need to treat it, but there’s no need to go crazy about it,” she said.

As for being overweight, Flegal and her colleagues have found that the condition carries an even lower risk of death.

Flegal’s study didn’t measure the contribution of weight to a host of chronic diseases such as Type 2 diabetes, hypertension and premature heart disease. But plenty of other studies have looked at that, including a voluminous report published in 1998 by a National Heart, Lung, and Blood Institute committee that is still considered the gold standard for diagnosis and treatment of excess body weight.

Here are some of the surprises:

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BMI shortcomings

Body mass index matters, but not as much as you might think. The BMI is a mathematical formula that uses height and weight to classify people as underweight, healthy weight, overweight or obese. A healthy BMI is 18.5 to 24.9; 25 to 29.9 is considered overweight; 30 and above is obese. To calculate your BMI, log on to the free electronic calculator at www.nhlbisupport.com/bmi.

Often overlooked is that BMI is meant to be paired with waist size (read more below) to help predict the risk of Type 2 diabetes, heart disease and high blood pressure. Although BMI is a useful screening tool to identify people who may be at elevated risk, it was never intended to be the sole measure. When the 1998 report made a BMI of 25 the threshold for overweight, some leading researchers criticized the move for being too arbitrary and unsupported by scientific data -- a debate that continues today. BMI can also fall short in accurately categorizing athletes, other muscular people with BMIs of 25 to 30 and the elderly. That’s because it does not take into account muscle mass and body fat percentages.

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Measure your waist

If you’re in the 25 to 29.9 BMI range but your waist is less than 35 inches (for women) and 40 inches (men), your odds of developing Type 2 diabetes and other chronic weight-related illnesses are significantly less than people with the same BMI but bigger waistlines. The same applies to those with BMIs from 30 to 34.9. For those with BMIs above 35, waistline is less important in the risk calculation.

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Keep the scale steady

The report by the National Heart, Lung, and Blood Institute says that if you fall into the overweight category, there’s no need to lose weight for health reasons unless you also have two or more of the following risk factors: elevated blood cholesterol, high blood pressure or high blood sugar. Absent those -- and provided that your waistline is less than 35 inches for women, 40 inches for men -- the goal should be to keep from gaining more weight. Several studies suggest that health risks, disability and diminished quality of life in old age are greatest for people with a BMI of 30 or more.

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When small is significant

Trimming a little weight helps a lot. Just 10% of your body weight -- 20 pounds for someone who weighs 200 -- should be the initial goal for overweight people with big waistlines or other risk factors, and for those with a BMI of 30 or higher. That’s because there’s good evidence to show that even a small weight loss significantly improves blood cholesterol, blood pressure and blood sugar levels.

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A healthful combo

The best way to shed pounds? The report says those with a BMI of 27 to 35 should cut 300 to 500 calories daily via a combination of less food and more activity. Skipping second helpings or forgoing an afternoon candy bar and walking for 30 minutes daily will pretty much do it. That adds up to a loss of about a half-pound to a pound per week.

For those with BMIs of 35 or higher, the report says to cut 500 to 1,000 calories daily by eating less and exercising more. Doing that could result in about a 1- to 2-pound loss per week -- which will produce that 10% weight loss over about six months.