FRIDAY, Nov. 14, 2008 (HealthDay News) -- Elite athletes are advised to "fill the tank" with an energy bar or sports drink soon after a workout.
But for mere mortals -- folks who are simply trying to keep their weight in check or stave off heart disease -- adding calories right after burning them up could negate the benefits of the sweat, researchers say.
"If people are going to go out and exercise to benefit their health, they should not be eating back the calories immediately upon finishing, or within a couple of hours of finishing," said Barry S. Braun, director of the Energy Metabolism Laboratory at the University of Massachusetts Amherst. "In order to maintain the benefits, you need to be in this calorie deficit."
"Athletes are always advised to do exactly the opposite," he continued. "That's great for athletes, but for the other 99.9 percent of the world, that's probably the wrong thing."
Braun is co-author of two papers appearing in the Journal of Applied Physiology, Nutrition and Metabolism and one paper published in the Journal of Applied Physiology that detail the findings.
Ten young, overweight men and women participated in each experiment.
For the first study, volunteers were asked to walk on a treadmill for an hour a day, burning about 500 calories each time. Half of the group were given a high-calorie carbohydrate drink immediately after their workout while the other half abstained.
Exercise increased insulin efficiency by 40 percent in those who did not eat afterwards. But the benefit was completely wiped out for those who had a high-carb drink after sweating.
These results had the researchers wondering if the type of calorie would make any difference.
For the second study, volunteers cycled for 75 minutes. Immediately after exercising, half of the participants ate a meal high in carbohydrates while the other half ate a meal low in carbohydrates but containing the same number of calories.
The ability of insulin to clear sugar from the blood was greater among people who ate the low-carb meal, the researchers found.
"It seems as though giving people back carbohydrates blunts or diminishes this exercise benefit," Braun said.
The third study was all about timing. Participants were given identical meals before, immediately after or three hours after cycling for 75 minutes.
The effectiveness of insulin was about the same no matter what the time, the study revealed.
"That really didn't make a whole lot of difference, which surprised us," Braun stated. "What did seem to matter was whether you ate back calories, and whether those calories were mostly carbohydrates."
More information
There's more on how to get the most out of your workout at the American College of Sports Medicine.
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Make Your Workout Work For You
There's more to a great fitness regimen than a positive attitude and a good pair of sneakers. Jim White, a registered dietitian, personal trainer and spokesman for the American Dietetic Association, offered these tips on maximizing your workout:
- Keep yourself well-hydrated. "Being dehydrated can drop levels of strength and aerobic capacity," White said. Drink at least eight eight-ounce glasses of water a day including about 16 ounces an hour before you exercise, four-to-eight ounces every 15 minutes during exercise and another 16 ounces an hour after you finish working out.
- Incorporate a 5-to-10 minute warm-up and light stretching before you start working out. "It could just be going on a bike or a treadmill," White said. "It warms up the muscles and gets your mind ready for exercising." And don't forget to stretch after you exercise.
- Get going with some music. "Studies show this leads to a workout that increases muscular strength and endurance," White said.
- Work out with a friend and partner. "This can be a good distraction and motivating," White said. "If you want to increase your workout intensity, find someone who's a little bit fitter than you are."
- Make sure you're getting enough sleep. "That's going to make sure your focus is there," White said.
- Time your workout to suit your schedule. "Some people love to jump start their day," White said. "I work out every single night. It's a matter of preference."
- Set workout goals and write them down at the beginning of each week. You'll be more likely to stick to them.
- Some experts recommend doing weight training first, followed by cardio. But, White said, "the biggest thing is just to do it."
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