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It’s still better to be fat and fit than thin and unfit

Humboldt Penguins are led to the weighing scales with a feed of anchovies to encourage them at London Zoo.
AP Photo/Alastair Grant
It’s not the weight, it’s what you do with it that counts.
Published Last updated This article is more than 2 years old.

As a new year begins, people flock to diets like lemmings to cliff edges. The bad news: Some 95% of those diets will fail in the long run, and many of us will wind up heavier and less healthy than when we started.

But there’s good news, too: Fitness may be even more important to your health than weight is. And fitness is something you can improve regardless of the number on the scale.

The latest in a series of studies (pdf) by researchers at the Cooper Institute in Dallas, as well as a meta-analysis (pdf) of other studies, have found that people with higher levels of cardiorespiratory fitness (a measure of how much oxygen your body uses during exercise) have less chance of early death than those with lower levels, even if they are considered overweight or obese. And it’s way better, healthwise, to be fat and fit than to be thin and unfit. “If you’re fit, it nullifies the apparent risk of high waist circumference or obesity,” says Paul McAuley, a professor of exercise science at the University of South Carolina. “Fitness is a powerful indicator of physical health.”

If this is true, why aren’t we hearing about it? One reason is that researchers, like the rest of us, are still entrenched in the “fat will kill you” mindset, and interpret their findings accordingly. For instance, pretty much all the research on weight loss involves some kind of change in lifestyle, often in the form of exercise. But researchers tend to attribute better health or lower mortality only to the weight lost, especially if those in the study drop from the “obese” or “overweight” categories into the “normal” one. They fail to explore the idea that it might be the exercise (and the better fitness that results) that makes the difference, rather than the weight itself.

Another reason is that many of the studies on weight and health don’t even ask participants about their fitness levels, let alone measure them. “Every week, in leading scientific medical journals around the world, I can see a finding on obesity and health condition X or Y,” grumbles Steven Blair, a professor of exercise science and epidemiology at the University of South Carolina. “I type in ‘physical activity’ and get ‘term not found.’ That is junk science. You cannot study health and weight without taking physical activity into account.”

Some experts believe that fitness accounts for some of the more puzzling findings on weight and health, like the so-called obesity paradox: that, among sufferers of chronic diseases like type 2 diabetes and heart disease, fatter people fare better and live longer than thinner ones. “Fitness seems to mitigate the relationship between fatness and [disease] prognosis,” says Carl Lavie, M.D., medical director of the Ochsner Heart and Vascular Institute in New Orleans. “It looks like it’s more important to maintain your fitness than your leanness.”

We still don’t fully understand exactly how fitness, weight, and health interact. But it’s clear that fitness is a crucial aspect of good health. So this year, resist the temptation to put yourself on a futile and potentially damaging diet, and find ways to get a little more active instead.

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