Does Diet and Exercise Really Matter?

In the end, whether a person is obese or thin has almost everything to do with genetics and nothing to do with lifestyle, writes Gina Kolata:

The findings also provided evidence for a phenomenon that scientists like Dr. Hirsch and Dr. Leibel were certain was true — each person has a comfortable weight range to which the body gravitates. The range might span 10 or 20 pounds: someone might be able to weigh 120 to 140 pounds without too much effort. Going much above or much below the natural weight range is difficult, however; the body resists by increasing or decreasing the appetite and changing the metabolism to push the weight back to the range it seeks.

The message is so at odds with the popular conception of weight loss —
the mantra that all a person has to do is eat less and exercise more —
that Dr. Jeffrey Friedman, an obesity researcher at the Rockefeller
University, tried to come up with an analogy that would convey what science has found about the powerful biological controls over body weight.

He published it in the journal Science in 2000 and still cites it:

“Those who doubt the power of basic drives, however, might note that although one can hold one’s breath, this conscious act is soon overcome by the compulsion to breathe,” Dr. Friedman wrote. “The feeling of hunger is intense and, if not as potent as the drive to breathe, is probably no less powerful than the drive to drink when one is thirsty.
This is the feeling the obese must resist after they have lost a significant amount of weight.”

The science Kolata cites to support the "comfortable weight range" is solid. But does it follow that dieting and exercise is irrelevant?

If anything, findings that naturally non-obese people who gorged themselves into obesity and quickly lost weight upon returning to a regular diet suggests that the U.S. obesity epidemic is reversible. And how might this reverse come about, if not through changing the very habits that led to a doubling of obesity in a single generation?

Genes Take Charge, and Diets Fall by the Wayside [New York Times]

Image: Melting Mama