Can A Person Be Both Fat and Fit?

There was a time not too long ago when fitness and fatness might have seemed mutually exclusive. Lately, however, the idea that you can be fit and fat at the same time has been debated with increasing frequency—and it’s not likely to go away any time soon.

There are a couple of reasons for this, and the first is simple desperation.

The percentage of Americans who are overweight or obese has been rising steadily for years. But the new twist on these numbers is that, more and more, people are giving up on even trying to lose their excess weight. Partly it’s because losing weight is hard. Partly it’s because of disappointment with a long history of diet schemes that just haven’t worked. And partly it’s because of a change of perception—as more and more people join the obese/overweight categories, it becomes more and more socially acceptable.

And so if healthcare professionals have failed in their attempts to stop this rising tide of weight gain, their fallback position is to increasingly ask the question: Well, can a person be both fat and fit?

And the other reason we’re hearing this question more often lately is that, yes, perhaps, maybe a person can.

A viewpoint essay recently in The JAMA Network summarized a number of recent studies under the headline Fitness or Fatness: Which is More Important? There’s plenty of evidence, according to the authors, that a better determiner of overall health is cardio-respiratory fitness (CRF, measured by a maximal treadmill exercise test), not body mass index (BMI). A number of long-term mortality studies, they report, found an increased risk of death for people with low CRF, no matter their BMI; and that there was no difference in risk of death between normal weight and overweight individuals if they had a comparable healthy CRF.

It’s an interesting idea, and perhaps even comforting. But it’s too soon, and the studies available are still too limited in scope, for people to use this as a justification for remaining overweight.

First of all, just because you can be overweight and healthy doesn’t mean you are. You still need to put in the work to achieve and maintain that cardio-respiratory fitness. That means you’re not off the hook as far as getting regular exercise. Another issue is that these studies all seem to use BMI as a measure of whether or not a person is overweight or obese — and BMI can be notoriously misleading, designating people with high muscle mass and low body fat as obese. So we can’t say for sure how many of the “overweight but fit” people in these studies actually just had really big muscles.

Still, it’s a hopeful sign that healthcare professionals might begin to look beyond the surface and consider other, more accurate indicators of a person’s health.

And once again, the takeaway from this report seems to be that, whether fat or thin, one of the best things we can do for ourselves is to exercise regularly.