Louis
10-08-2007, 04:09 PM
From the NYT
And Now, the Exercise-Resistant Dieter
Exercise affects each person differently, a new study finds.
(Susan Farley for The New York Times.)
Moderate exercise may not do much to help you lose weight, research shows. But even intense exercise is no guarantee of weight loss, according to a new study from the University of Leeds in Britain.
Thirty-five overweight men and women took part in supervised exercise designed to burn 500 calories a day on treadmills, bikes and rowing machines. By the end of the 12-week study, some exercisers had lost a staggering 32 pounds. But five of them actually had gained weight — as much as four pounds, according to the researchers, who published their findings last month in the International Journal of Obesity.
Most volunteers fell somewhere in the middle, losing only a few pounds despite the regimen. Unsurprisingly, the data did suggest that the people who failed to lose much weight had slightly increased their calorie intake by the end of the study (by about 270 calories), while the people who lost more weight had slightly decreased their intake (about 130 calories). But the differences in how the subjects ate compared to the beginning of the study were not statistically significant, according to the report.
The finding shouldn’t be surprising, the investigators added, given what we already know about the variability of patient responses to drugs and other medical treatments. Most major drugs are effective in only 25 to 60 percent of patients, The New England Journal of Medicine noted in 2005. While millions of people take drugs safely, there are more than two million adverse drug reactions annually in the United States, including 100,000 deaths.
It makes sense, then, that the body can respond in a variety of ways to exercise. The challenge for science is to figure out why exercise helps some people lose weight but not others.
Simple math tells us that it takes a tremendous amount of exercise to burn a meaningful number of calories. Depending on your weight, for example, a mile jog might burn about 100 calories. In theory, that means it would take 35 such jogs to lose a single pound. But as this study demonstrates, the math doesn’t always work so neatly. The body does everything it can to steal back the calories you are so desperately trying to work off, studies have found, and different bodies do it at different rates. Resting metabolism may slow, for instance, or appetite may increase as the body strives to maintain its weight. Some research suggests that heavy exercisers may unknowingly move more slowly during the periods when they aren’t exercising.
The bottom line is that the best reason for moderate exercise is that it makes you feel good and helps you live longer and healthier. Moderate exercise may also help some people lose weight — but clearly not everyone.
And Now, the Exercise-Resistant Dieter
Exercise affects each person differently, a new study finds.
(Susan Farley for The New York Times.)
Moderate exercise may not do much to help you lose weight, research shows. But even intense exercise is no guarantee of weight loss, according to a new study from the University of Leeds in Britain.
Thirty-five overweight men and women took part in supervised exercise designed to burn 500 calories a day on treadmills, bikes and rowing machines. By the end of the 12-week study, some exercisers had lost a staggering 32 pounds. But five of them actually had gained weight — as much as four pounds, according to the researchers, who published their findings last month in the International Journal of Obesity.
Most volunteers fell somewhere in the middle, losing only a few pounds despite the regimen. Unsurprisingly, the data did suggest that the people who failed to lose much weight had slightly increased their calorie intake by the end of the study (by about 270 calories), while the people who lost more weight had slightly decreased their intake (about 130 calories). But the differences in how the subjects ate compared to the beginning of the study were not statistically significant, according to the report.
The finding shouldn’t be surprising, the investigators added, given what we already know about the variability of patient responses to drugs and other medical treatments. Most major drugs are effective in only 25 to 60 percent of patients, The New England Journal of Medicine noted in 2005. While millions of people take drugs safely, there are more than two million adverse drug reactions annually in the United States, including 100,000 deaths.
It makes sense, then, that the body can respond in a variety of ways to exercise. The challenge for science is to figure out why exercise helps some people lose weight but not others.
Simple math tells us that it takes a tremendous amount of exercise to burn a meaningful number of calories. Depending on your weight, for example, a mile jog might burn about 100 calories. In theory, that means it would take 35 such jogs to lose a single pound. But as this study demonstrates, the math doesn’t always work so neatly. The body does everything it can to steal back the calories you are so desperately trying to work off, studies have found, and different bodies do it at different rates. Resting metabolism may slow, for instance, or appetite may increase as the body strives to maintain its weight. Some research suggests that heavy exercisers may unknowingly move more slowly during the periods when they aren’t exercising.
The bottom line is that the best reason for moderate exercise is that it makes you feel good and helps you live longer and healthier. Moderate exercise may also help some people lose weight — but clearly not everyone.