For most of us, the fear of flab is the reason we exercise, the motivation that drives us to the gym. But you must know people who slog away and never lose weight (I know somebody who 20 years ago, was short, balding and fat. Today he's still short, bald and fatter. And that's after jogging steadily for two decades). If we acknowledge that these types of folks exist, then we also need to recognize that although on average exercise may have clear benefits, it may not do the one thing we want from exercise: to lose weight. Despite their decades of efforts to prove otherwise, scientists still can t say for certain that exercise can keep the pounds off. If anything, exercise can make you fat. How can this paradox be since exercise burns energy? Well, because exercise does not burn energy; it redirects energy into fat. The human body is very protective of its parts. If you burn more fat, the body will re-supply more of it. This holds true for every body - fat people, old people, bicyclists, joggers and body builders, people who work out endlessly, almost never, occasionally or a little daily, walking on treadmills, cycling or pumping iron. The one thing that might be said with certainty about exercise is that it tends to make us hungry. It works up an appetite. Burn more calories and the odds are very good that we ll consume more as well. It becomes a vicious circle hard to exit from. I worked out today; therefore I can eat fattening foods to my heart s content. But maybe the causality is reversed. Maybe it s because we eat foods that fatten us that the workout becomes a necessity. The problem is that exercise burns an insignificant number of calories, amounts that are undone by comparatively effortless changes in diet. In the 1940s, an American scientist calculated that a man will have to climb 20 flights of stairs to rid himself of the energy contained in one slice of bread. If I was the guinea pig, I'd take the elevator, and take the bread. In other words, walking one half-hour a day may be equivalent to only four slices of bread, but if you don't walk the half-hour, you probably still want to eat the four slices. To people who insist that exercise has been the key to their weight-loss programs, the one thing we d have to wonder is whether they changed their diets as well. Rare is the person who decides the time has come to lose weight and doesn t also decide perhaps it s time to eat fewer sweets, drink less sodas, switch to diet drinks, and maybe curtail the kind of carb-rich snacks - the potato chips and the candy bars - that might be singularly responsible for driving up their fat. This is not to say that there aren t excellent reasons to be physically active. The benefits of exercise are innumerable. It's great for oxygen consumption, cardiac output, blood pressure, heart rate and other markers of fitness. We may increase our overall fitness; perhaps reduce our risk of heart disease or diabetes; and we ll probably feel better about ourselves. Exercise might even prevent you from going to an early grave, although only God knows when. But there s no reason to think we will lose any significant amount of weight, and little reason to think we will prevent ourselves from gaining it. Some people may do better to change their diet. It's also possible that you have some genetic predisposition to obesity. In that case, exercise for the sake of shedding kilos, especially the kind around your middle, is an exercise in futility.
