Sunday, October 5, 2008

Moderate Exercise and Weight Loss

For years, we’ve been told that a few minutes of moderate exercise a day will lead to amazing health benefits. A new study, though, indicates that significant weight loss isn’t among them:

Obesity experts agree that daily exercise is essential for good health, but whether it can successfully lead to long-term weight loss is a question of much debate. What has become increasingly clear, however, is that the conventionally accepted advice — 30 minutes of moderate-intensity activity most days of the week — is probably insufficient to spur any real change in a person’s body weight. A study published July 28 in the Archives of Internal Medicine adds to the burgeoning scientific consensus: when it comes to exercise for weight loss, more is better. It suggests that obese people would have to exercise at least an hour at a time to see any significant difference in their weight.

Which stands to reason, really. My lifestyle is pretty sedentary during the week: Wake up, work in front of the computer for a couple of hours, drive to the office, sit in front of the computer a few hours, drive home, sit in front of the computer some more, eat dinner, sit in front of the television for a couple hours, go to bed. Even so, I probably walk 30 minutes a day just between my desk, the coffee machine, and the bathroom. Walking to get lunch, on the days I don’t bring my own, probably gives me 20 minutes. Simply put, it’s ridiculously hard not to get 30 minutes of moderate activity on a daily basis if you’re able bodied.

Of course, no report on obesity would be complete without a “not that there’s anything wrong with that” disclaimer telling you it’s not your fault:

Still, the underlying question remains: are diet and exercise a reliable cure for obesity? Modern-day obesity researchers are skeptical — achieving thinness, they say, is not simply a matter of willpower. Research suggests that weight may largely be regulated by biology, which helps determine the body’s “set point,” a weight range of about 10 lbs. to 20 lbs. that the body tries hard to defend. The further you push you weight beyond your set point — either up or down the scale — some researchers say, the more your body struggles to return to it. That might help to explain why none of the women in Jakicic’s study managed to lose much more than 10% of their body weight. After two years on a calorie-restricted diet, keeping up more than an hour of physical activity five days a week on average, most were still clinically overweight (though much less so than before). But what Jakicic and other obesity researchers stress is that a 10% reduction in body weight represents a tremendous boon for overall well-being, lowering blood pressure, improving heart health and reducing the risk of Type 2 diabetes. For the obese, the end goal should not be thinness, but health and self-acceptance, which are more realistic and beneficial objectives. “The women’s health was absolutely improved,” Jakicic says.

What none of these studies ever explain to my satisfaction is why, if obesity is essentially random, it suddenly appeared on a large scale in Western society about thirty years ago and why you don’t see random fit kids in those television reports of famine in Africa.