According to a HealthDay News article, a recent study suggests that the type of calories you consume before a workout may influence the amount of calories you burn during your workout.
Women who ate breakfast high in calories that do not cause blood sugar to increase (low-glycemic index carbs) e.g. yogurt, skimmed milk, etc., burned 50 percent more fat than those who consumed carbohydrates that make blood sugar to rise sharply (high-glycemic index carbs).
Other studies also discovered that a diet of low-glycemic carbs aids in fat-burning, this study led by Emma Stevenson, a senior lecturer at Northumbria University, Newcastle Upon Tyne, U.K has some unique points.
"Most of the research in the effects of the glycemic load of pre-exercise feeding has been carried out in male subjects," Stevenson said. Most of it also has focused on endurance athletes, which doesn’t describe the bulk of the population."
This study observed eight women of typical healthy weight, and who averaged 24 years of age. On two separate instances, the women were given either a high- or low-glycemic index breakfast, and then 3 hours later were asked to walk on the treadmill for 60 minutes. The researchers took blood samples before the breakfast, and during and after the exercise to measure factors such as free fatty acids, which are a fat-burning indicator.
After a low-glycemic meal, the average amount of fat oxidized during the exercise was 7.4 grams. On the other hand, after a high-glycemic meal, the amount was 3.4 grams.
The reason for the discrepancy, the researchers believe, is a meal rich in low-glycemic carbs may enhance the body’s use of fat for burning rather than for blood sugar.
Each of the women’s breakfast amount to265 calories, but the researchers noted that the low-glycemic meals had more calories.
To dieters, Stevenson says: To burn more fat, focus on the low-glycemic foods. "LGI foods tend to be whole grains, porridge, some whole grain cereals, soy and linseed bread," she said.
According to Barry Braun, director of the Energy Metabolism Laboratory at the University of Massachusetts, Amherst, Stevenson’s research "makes sense and builds on previous research."
Braun, who has done his own study on post-workout eating, thinks that though Stevenson’s research findings are limited healthy-weight women, they will yield the same results for those who want to lose weight.
"Eating large amounts of high-glycemic carbs right before exercise is probably as detrimental for overweight people as it is for normal-weight," he said.