06/11/2009 05:12 am ET | Updated Nov 17, 2011

A Supreme Court Justice Can be Fat and Fit

Ever since a very fit President Obama announced that seemingly fit Supreme Court Justice David H. Souter had tendered his resignation on May 1, there has been much discussion about the health qualifications of the potential nominees, with a particular emphasis on their weight. Concerns have arisen that some of the candidates may not be healthy (and should therefore not be considered for such a long-term post) because they're carrying extra pounds.

I am here to tell you that you can be fat and fit. Appearances can be deceiving.

This idea is not new. In fact, the term "fat and fit" was originally coined by Dr. Steven N. Blair, one of the world's leading exercise scientists, who is currently a professor at the University of South Carolina. For more than 25 years Blair and his associates have been looking at how fitness, fatness, and health outcomes are related. And what they have found is that cardiorespiratory fitness is a better predictor of who will die, and when, than BMI (body mass index), a calculation of body fat based on height and weight. In other words, according to Blair, fitness appears to provide protection against the risk of early mortality posed by fatness. In fact, his research shows that the death rate for women and men who are thin but unfit is at least twice as high as for their obese counterparts who are fit.

I witness the fat-and-fit phenomenon in my preventive cardiology practice every day. Into my examining room will walk a considerably overweight, pear-shaped female who will turn out to have the blood chemistry of a vegetarian marathoner because she actually gets out and walks on a regular basis. Her HDL ("good") cholesterol and triglycerides are excellent and her tests show she is at very low risk for heart disease. My next patient will be a seemingly fit, normal-weight man, who turns out to have terrible blood lipids and is at high risk for heart attack, stroke, and many other diseases. Even though he looks great at first glance, he's actually carrying his "normal" weight as fat (typically a highly inflammatory little bowling ball in his belly), not muscle, because he doesn't exercise. That's why I always go by a person's physiologic risk factors, rather than by BMIs or weight tables.

This was recently backed up by a study of 5,440 adults reported in the August 2008 Archives of Internal Medicine. It found that half of the overweight and one-third of the obese participants were "metabolically healthy." This means they had few, if any, risk factors for heart disease, such as high blood pressure or low levels of HDL cholesterol. The study also found that about one-fourth of the "normal" weight people were "metabolically unhealthy" and exhibited cardiovascular risk factors. The study did not measure fitness levels, as Blair has done.

This said, I don't want you to think that being fat is good. Or, conversely, that being too thin (and unfit) is fine. There is no question that our bellies have grown. Federal health surveys show that, over the past four decades, the mean waist size for men has increased from 35 inches to 39 inches; for women, from 30 inches to 37 inches. The number of people suffering from coronary heart disease, diabetes, arthritis, and other inflammatory conditions has also grown. And while exercise can turn the tide for some, those who don't exercise and continue to eat a nutrient-poor diet, smoke, and drink too much will continue to feed the obesity (and heart disease and diabetes) epidemic in this country. The solution for these people is to focus on making better lifestyle choices overall rather than simply dwelling on a number on the scale.

I can't speak for whether our Supreme Court candidates are fat and fit or not. But I can tell you not to judge a book (or a judge) by its cover.

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