I found the article gave as many theories as the "experts" it quoted, but found a few things interesting:
The effects of exercise on the appetite and energy systems, however, are by no means consistent. In one study presented last year at the annual conference of the American College of Sports Medicine, when healthy young men ran for an hour and a half on a treadmill at a fairly high intensity, their blood concentrations of acylated ghrelin fell, and food held little appeal for the rest of that day. Exercise blunted their appetites. A study that Braun oversaw and that was published last year by The American Journal of Physiology had a slightly different outcome. In it, 18 overweight men and women walked on treadmills in multiple sessions while either eating enough that day to replace the calories burned during exercise or not. Afterward, the men displayed little or no changes in their energy-regulating hormones or their appetites, much as in the other study. But the women uniformly had increased blood concentrations of acylated ghrelin and decreased concentrations of insulin after the sessions in which they had eaten less than they had burned. Their bodies were directing them to replace the lost calories. In physiological terms, the results “are consistent with the paradigm that mechanisms to maintain body fat are more effective in women,” Braun and his colleagues wrote. In practical terms, the results are scientific proof that life is unfair. Female bodies, inspired almost certainly “by a biological need to maintain energy stores for reproduction,” Braun says, fight hard to hold on to every ounce of fat. Exercise for many women (and for some men) increases the desire to eat.
On the other hand, if you can somehow pry off the pounds, exercise may be the most important element in keeping the weight off. “When you look at the results in the National Weight Control Registry,” Braun says, “you see over and over that exercise is one constant among people who’ve maintained their weight loss.” About 90 percent of the people in the registry who have shed pounds and kept them at bay worked out, a result also seen in recent studies.
But the exercising rats metabolized calories differently. They tended to burn fat immediately after their meals, while the sedentary rats’ bodies preferentially burned carbohydrates and sent the fat off to be stored in fat cells. The running rats’ bodies, meanwhile, also produced signals suggesting that they were satiated and didn’t need more kibble. Although the treadmill exercisers regained some weight, their relapses were not as extreme. Exercise “re-established the homeostatic steady state between intake and expenditure to defend a lower body weight,” the study authors concluded. Running had remade the rats’ bodies so that they ate less.
I found the article gave as many theories as the "experts" it quoted, but found a few things interesting:
The effects of exercise on the appetite and energy systems, however, are by no means consistent. In one study presented last year at the annual conference of the American College of Sports Medicine, when healthy young men ran for an hour and a half on a treadmill at a fairly high intensity, their blood concentrations of acylated ghrelin fell, and food held little appeal for the rest of that day. Exercise blunted their appetites. A study that Braun oversaw and that was published last year by The American Journal of Physiology had a slightly different outcome. In it, 18 overweight men and women walked on treadmills in multiple sessions while either eating enough that day to replace the calories burned during exercise or not. Afterward, the men displayed little or no changes in their energy-regulating hormones or their appetites, much as in the other study. But the women uniformly had increased blood concentrations of acylated ghrelin and decreased concentrations of insulin after the sessions in which they had eaten less than they had burned. Their bodies were directing them to replace the lost calories. In physiological terms, the results “are consistent with the paradigm that mechanisms to maintain body fat are more effective in women,” Braun and his colleagues wrote. In practical terms, the results are scientific proof that life is unfair. Female bodies, inspired almost certainly “by a biological need to maintain energy stores for reproduction,” Braun says, fight hard to hold on to every ounce of fat. Exercise for many women (and for some men) increases the desire to eat.
On the other hand, if you can somehow pry off the pounds, exercise may be the most important element in keeping the weight off. “When you look at the results in the National Weight Control Registry,” Braun says, “you see over and over that exercise is one constant among people who’ve maintained their weight loss.” About 90 percent of the people in the registry who have shed pounds and kept them at bay worked out, a result also seen in recent studies.
But the exercising rats metabolized calories differently. They tended to burn fat immediately after their meals, while the sedentary rats’ bodies preferentially burned carbohydrates and sent the fat off to be stored in fat cells. The running rats’ bodies, meanwhile, also produced signals suggesting that they were satiated and didn’t need more kibble. Although the treadmill exercisers regained some weight, their relapses were not as extreme. Exercise “re-established the homeostatic steady state between intake and expenditure to defend a lower body weight,” the study authors concluded. Running had remade the rats’ bodies so that they ate less.
