Research Communications

Fat Fighters: Eating the right carbohydrates may boost the benefits of exercise 

By Adam Liebendorfer
March 19, 2012

What you eat after a workout could help your body keep burning fat, a new Ohio University study finds.

Junior exercise physiology major Ryan Lubbe examined the impact of eating either high- or low-glycemic index foods after exercising. Dieticians developed the index to gauge how carbohydrates affect blood sugar levels in the body. Carbs with higher glycemic indexes, such as pretzels, break down faster and release sugar into the bloodstream more quickly than lower glycemic index foods, such as dairy products, fruit, and whole grains, which give the body energy gradually over a longer period of time.

 Eating the right carbohydrates may boost the benefits of exercise
Junior Ryan Lubbe, right, won an award for his study on carbohydrates and exercise. (Photo credit: Robb DeCamp.)

In the study, 10 college-age men participated in three trials: They burned 300 calories on a treadmill and then ate three different simulated “meals.” In one trial, Lubbe fed the exercisers sugar water to represent a meal with a high-glycemic index. In another, he fed them low-glycemic carbohydrates, and in the third, the subjects drank only water. 

He then tested participants periodically over the next two hours to determine the ratio of carbon dioxide exhaled to oxygen consumed, an indicator for what the body uses as a source of fuel. When more oxygen is consumed than carbon dioxide is exhaled, he explains, more fat is being burned for energy.

When participants consumed the high-glycemic sugar water after a workout, their bodies quickly began using the carbohydrates instead of relying on the body’s fat stores. But the other two meals–the low-glycemic index carbohydrate and the water–both allowed participants to keep burning more fat.

“We’re promoting exercise, but it’s tough to get out and run and whatnot,” Lubbe says. “The choices that you make diet-wise can either negatively or positively affect the benefits of exercise.”

The research was funded by the Provost’s Undergraduate Research Fund and advised by Michael Kushnick, associate professor of exercise physiology. Lubbe presented the findings from the exhalation tests at the 2011 Ohio University Student Research and Creativity Expo.

The future medical student now is analyzing the 120 blood samples he and other researchers collected during the trials, examining glucose, fatty acids, and insulin to more precisely determine which sources the participants’ bodies tapped for energy.

Those results will be part of a future journal article and were the subject of his presentation to the Midwest American College of Sports Medicine’s 2011 conference, where Lubbe won an outstanding presentation award. His trip to the conference was supported by the Ohio University Undergraduate Conference Travel Fund.

This article will appear in the Spring/Summer 2012 issue of Perspectives magazine, which covers Ohio University research, scholarship, and creative activity.