Do you really need to exercise?


There is, it seems, devilry in the details regarding exercise.   This, according to the cover story in this week’s Time Magazine, which cites studies and experts to make the case that exercise is not highly effective for weight loss.  This has long been common knowledge, and is about as informative as noting that mittens are not highly effective at keeping you warm—unless you wear something else, too.  And worse than that, it’s dangerous—because in a society that is more fixated on weight than health and not nearly as active as it should be, this high-profile disparagement of exercise may be all it takes to dissuade even more of us from doing any.  That would be a shame at best, tragic at worst.

There is a great deal of myth in Time‘s myths about exercise, and where there isn’t actual myth, there is misrepresentation.  Let’s get to it:

1) Exercise is vitally important to overall health. No one really disputes this—and a study just out in the Archives of Internal Medicine reaffirms it.  This study, for which I wrote the accompanying editorial, showed that exercise was one of just four behaviors that could, all by itself, reduce the risk of chronic disease and premature death by roughly 50%! So first and foremost, let’s reconsider whether all we care about is being thin, no matter what our health.  Anyone who thinks that thinness matters but health doesn’t may want to give cholera a try.  Everyone else … should exercise!

2) You’ll look better—even if you weigh more. I trust you all remember that school-yard brain tease: Which is heavier, a pound of feathers or a pound of iron? They’re  the same, both a pound, of course.  But the feathers would take up a lot more space.  Well… the same is true of a pound of fat or a pound of muscle.  Muscle is far denser.  Exercise builds muscle.  As you go from sedentary to active, and build muscle, you could actually get HEAVIER as you get leaner, simply because you are getting denser.  That’s a good thing!  I saw a dramatic case of this as the doctor on the first season of VH1’s Celebrity Fit Club, when comedian Ralphie May—weighing in at over 400 lbs—lost fat, but not weight.  Why?  He was exercising with a 400lb load to carry, and thus built a lot of muscle.  The scale did not show the results of his impressive effort, but body composition analysis did.  We used bio-electrical impedance to show that of all the show participants, he had lost the most body fat, and built the most muscle.

The Time article cites a study in which exercising women did not lose “weight” as compared to sedentary counterparts.  But that doesn’t mean they did not lose fat, and get both leaner and healthier.  In fact, I am certain they did.  Show me the body comp data! There is only so much a scale can tell us.

3) What you eat still matters. Food is the fuel that runs the human body—and that provides the construction material for the renewal of our cells, the growth of our children.  The quality of that fuel and those construction materials matters.  Duh.

And, of course, the quantity matters, too.  In a modern age that makes tasty calories abundantly, ubiquitously available of course everyone but the most extreme, ultra-athletes (think Tour de France) can eat back all the calories they burn, and then some.  It is unfair to expect weight loss from the “calories out” side of the equation, while ignoring the “calories in” side.  All that goes in, must come out; all of the calories we consume must be burned, or the excess will go into storage as body fat. It’s far more about math than it is about myth.

My advice: Use fuel-burning exercise as a good excuse to improve the quality of the fuel you are burning.  One advantage of the most nutritious foods—vegetables, fruits, beans, lentils, fish, nuts, and so on—is that they fill us up on fewer calories than the highly processed alternatives.  Even if exercise increases your appetite, choose the right foods and you can fill the tank without tossing in a surplus of calories.

Bottom line: Physical activity is vitally important to health.  And it is, indeed, of fundamental importance to lasting weight control and the construction and maintenance of lean body mass in lieu of fat.  Being physically active will help make you lean, and is very likely to add both years to your life, and vitality to your years.  Don’t give in to the devilry of distraction.

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