Exercise and Fat Burning continued...
But they found that burning of carbohydrate, not fat, seemed to increase in the 24-hour period after exercising.
In the journal report, Melanson reports additional fat-burning studies, including one that compared seven men ages 60-75 with seven other men ages 20-30, with no differences in fat burning between groups for the 24 hours after exercise or no exercise.
Why don't we become long-term fat burners after a good workout? The most likely reason is that we eat. And what we eat affects fat burning.
For instance, eating as little as 240 calories of carbohydrate during the hour before exercise can reduce fat burning during exercise, and the boost in fat burning during exercise can be "blunted" for up to six hours after eating a meal, says Melanson, citing other research.
To maintain their low body fat, endurance-trained exercisers may simply eat less fat than they burn habitually, he says.
Fat Burning: Calories Count
The study findings are ''dispelling the myth that you can create a 24-hour fat-burning situation after exercise," says Pete McCall, an exercise physiologist and spokesman for the American Council on Exercise.
But, he tells WebMD, the findings were limited to exercisers who did moderate-intensity exercise, and for an hour or less. "These results might not apply to different forms of exercise or higher-intensity exercise," McCall says.
Still, he says, the research results might be a crucial wake-up call. "The point of this study, I think, is [that] he is trying to get people out of that mind-set: 'I just worked out and I can eat whatever I want.'" At least for people trying to lose weight, McCall says, that's certainly not true.
Melanson says that the take-home message from his research depends on whether you are trying to lose weight or just maintain. "If you are using exercise to lose body weight or body fat, you have to consider how many calories you are expending and how many you are taking in," he says. The goal is a negative fat balance.
"If your body mass index is below 25, you shouldn't be concerned about losing more body fat," he says.