While John Cloud erred in several ways in his Time magazine article titled Why Exercise Won’t Make You Thin, he's correct on the fat loss issue. Many people including the Surgeon General have lambasted Mr. Cloud for his candor and scientifically sound information on getting svelte.
Also from Jake’s Huff Post blog (he is quoting Dr. Robert
Sallis, past president of the
"If exercise were a pharmaceutical it would be the most potent drug ever invented. Exercise has been clearly proven to prevent and treat chronic diseases and lower mortality rates. From a scientific perspective, any attempt to discredit the value of exercise is just laughable and potentially very harmful to the public. As a physician who works hard to get patients more active, I find it very irresponsible for Time magazine to run a story that so misrepresents the facts."
Well, Dr. Sallis isn’t quite correct. All of the studies done on exercise that are used as iron clad proof that exercise prevents and treats chronic disease and lowers mortality rates are epidemiological / observational studies. These types of studies are not controlled research studies. They can only suggest an association - they do not prove cause and effect. Just because people who exercise regulary live longer and are generally healthier than those who don’t doesn’t mean that the exercise caused these benefits.
But why? Why does exercise have little to no effect on fat
loss? There are many reasons including increased appetite and being more
sedentary after the workout. An interesting example of this was watching my
daughters ride their bikes around
But the most important issue is the understanding of the language of fat loss. What tells the body to release fat from the fat cells?
Fat loss is not a numbers game. In other words, a calorie is not always just a calorie. Fat loss is a hormonal game. Fat is not released from the fat cells because you burn calories doing exercise. No one loses fat without altering their diet and sticking to that alteration. And the specific alteration is a reduction in carbohydrates, not necessarily calories, which in turn reduces insulin secretion, which in turn allows the lipids to be released form the fat cell. That's the biochemistry. We don't get to vote on it. There are other issues, but this is far and away the most critical.
And why do so many experts and the ACSM assume exercise will work even though time and time again research fails to support the assumption. So too do the failures of millions of Americans who try to shed the pounds by sweating to the oldies.
A thorough read of Gary Taubes' book Good
Calories Bad Calories explains this in great detail. According to
"Obesity is a disorder of excess fat accumulation. So the question everyone should be asking and always should have been asking is what factors regulate fat accumulation? As it turns out we've known that since the 1960s and it is not controversial. You can find it in endocrinology and biochemistry textbooks, just not in obesity textbooks. Fat accumulation is fundamentally determined by the hormone insulin and our insulin levels go up and down with the quantity and quality of carbohydrates we consume. The more carbs we eat, the more refined they are and the sweeter they are (the more fructose in them, in other words), the more insulin we will ultimately secrete. The higher our insulin levels, the more fat we accumulate."
Exercise cannot and does not solve the problem of fat release from the fat cell. The real key to the fat cell is not exercise. It is the control of hormonal tone and the most important hormone to control is insulin.
As the late Carl Sagan said: "Science as a candle in the dark."