[cnn-photo-caption image= http://i2.cdn.turner.com/cnn/2009/images/08/07/art.treadmill.gi.jpg caption="Whether because exercise makes us hungry or because we want to reward ourselves, many people eat more — and eat more junk food, like doughnuts — after going to the gym."]
As I write this, tomorrow is Tuesday, which is a cardio day. I'll spend five minutes warming up on the VersaClimber, a towering machine that requires you to move your arms and legs simultaneously. Then I'll do 30 minutes on a stair mill. On Wednesday a personal trainer will work me like a farm animal for an hour, sometimes to the point that I am dizzy — an abuse for which I pay as much as I spend on groceries in a week. Thursday is "body wedge" class, which involves another exercise contraption, this one a large foam wedge from which I will push myself up in various hateful ways for an hour. Friday will bring a 5.5-mile run, the extra half-mile my grueling expiation of any gastronomical indulgences during the week.
I have exercised like this — obsessively, a bit grimly — for years, but recently I began to wonder: Why am I doing this? Except for a two-year period at the end of an unhappy relationship — a period when I self-medicated with lots of Italian desserts — I have never been overweight. One of the most widely accepted, commonly repeated assumptions in our culture is that if you exercise, you will lose weight. But I exercise all the time, and since I ended that relationship and cut most of those desserts, my weight has returned to the same 163 lb. it has been most of my adult life. I still have gut fat that hangs over my belt when I sit. Why isn't all the exercise wiping it out?
It's a question many of us could ask. More than 45 million Americans now belong to a health club, up from 23 million in 1993. We spend some $19 billion a year on gym memberships. Of course, some people join and never go. Still, as one major study — the Minnesota Heart Survey — found, more of us at least say we exercise regularly. The survey ran from 1980, when only 47% of respondents said they engaged in regular exercise, to 2000, when the figure had grown to 57%.
And yet obesity figures have risen dramatically in the same period: a third of Americans are obese, and another third count as overweight by the Federal Government's definition. Yes, it's entirely possible that those of us who regularly go to the gym would weigh even more if we exercised less. But like many other people, I get hungry after I exercise, so I often eat more on the days I work out than on the days I don't. Could exercise actually be keeping me from losing weight?