If you’re going to do long-duration exercise, carbs are still your body’s preferred fuel source. But what about shorter workouts? New research shows that if you enjoy high-intensity interval training, there’s much less need to fill up with carbs before your workout.
Examine.com recently shared a study where scientists compared exercise performance on different levels of carbs. (You can see a detailed summary here). The research suggests that having more carbs in your system does not improve performance on high-intensity, shorter-duration workouts.
Here’s the science: your body’s primary fuel source is something called glycogen, which is stored carbohydrates. When training at a high intensity for more than an hour, your body taps into glycogen to keep you going. But when you need less time, the role of glycogen isn’t as important.
But that’s not to say carbs don’t matter. The study compared moderate to high amounts of carbs. In both situations, participants had glycogen (carbs) in the tank. But those with a fuel tank didn’t perform better on intense 15-minute workouts. However, other studies show that performance can drop off when carbs are very low. This might occur because glycogen also affects how your body releases calcium, directly influencing muscle contractions and force.
As a general rule of thumb, if you had carbs the night before and train in the morning, you don’t need pre-workout carbs (you can have them if you want, but your tank will still be full). But if you’re training later in the day, aim for an average of 20 to 40 grams of carbohydrates (about the amount of an apple, banana, or two slices of bread) within a few hours of your workout and combine with about 15 to 30 grams of protein. And if you feel best without eating, there’s no need to force a meal. At the end of the day, personal preference is part of maximizing potential performance.
—
Photo Credit: Mladen Zivkovic / Shutterstock.com