Why We Get Fat: And What to Do About It by Gary Taubes Read Free Book Online Page B

overeating is not a cause.
    * This wasn’t the only disappointing result in the study. The WHI investigators also reported that the low-fat diet failed to prevent heart disease, cancer, or anything else.
    † This calculation is oversimplified to make a point. If it is corrected for the observation that subjects who lose weight in diet studies expend less energy as they do it, then the amount of weight loss expected with this energy deficit should be less: approximately 1.6 pounds at three weeks and twenty-two pounds at one year. I owe this correction to Kevin Hall, a biophysicist at the NIH, who points out that the corrected numbers are “still a far cry from the observed value!”
    * Although Stunkard’s analysis has widely been perceived as a condemnation of all methods of dietary treatment of obesity, the studies he reviewed included only calorie-restricted diets.
    † I don’t count the WHI low-fat diet trial, because that was aimed at preventing heart disease and cancer, not losing weight.

3
The Elusive Benefits of Exercise
    Imagine you’re invited to a celebratory dinner. The chef’s talent is legendary, and the invitation says that this particular dinner is going to be a feast of monumental proportions. Bring your appetite, you’re told—come hungry. How would you do it?
    You might try to eat less over the course of the day—maybe even skip lunch, or breakfast and lunch. You might go to the gym for a particularly vigorous workout, or go for a longer run or swim than usual, to work up an appetite. You might even decide to walk to the dinner, rather than drive, for the same reason.
    Now let’s think about this for a moment. The instructions that we’re constantly being given to lose weight—eat less (decrease the calories we take in) and exercise more (increase the calories we expend)—are the very same things we’ll do if our purpose is to make ourselves hungry, to build up an appetite, to eat more. Now the existence of an obesity epidemic coincident with half a century of advice to eat less and exercise more begins to look less paradoxical. *
    We’ve seen the problems with eating less to produce weight loss. Now let’s examine the flip side of the calories-in/calories-out equation. What happens when we increase our energy expenditure by upping our level of physical activity?
    It’s now commonly believed that sedentary behavior is as much a cause of our weight problems as how much we eat. And because the likelihood that we’ll get heart disease, diabetes, and cancer increases the fatter we become, the supposedly sedentary nature of our lives is now considered a causal factor in these diseases as well. Regular exercise is now seen as an essential means of prevention for all the chronic ailments of our day (except, of course, those of joints and muscles that are caused by excessive exercise).
    Considering the ubiquity of the message, the hold it has on our lives, and the elegant simplicity of the notion—burn calories, lose weight, prevent disease—wouldn’t it be nice if it were true? As a culture, we certainly believe it is. Faith in the health benefit of physical activity is now so deeply ingrained in our consciousness that it’s often considered the one fact in the controversial science of health and lifestyle that must never be questioned.
    There are indeed excellent reasons to exercise regularly. We can increase our endurance and fitness by doing so; we may live longer, perhaps, as the experts suggest, by reducing our risk of heart disease or diabetes. (Although this has yet to be rigorously tested.) We may simply feel better about ourselves, and it’s quite clear that many of us who do exercise regularly, as I do, become exceedingly fond of the activity. But the question I want to explore here is not whether exercise is fun or good for us (whatever that ultimately means) or a necessary adjunct of a healthy lifestyle, as the authorities are constantly telling us, but whether it will help us