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There have probably been days where you’ve woken up to log your morning miles and skipped out on breakfast before heading out the door. Maybe you were in a rush to meet your running buddy and didn’t have time to whip something up, or maybe you just weren’t that hungry.
But there’s a reason it’s been nicknamed “the most important meal of the day,” and a new study published in the American Journal of Physiology: Endocrinology and Metabolism only confirms this.
Researchers from the University of Bath’s Department for Health studied how eating before a workout impacts your performance as opposed to fasting overnight by splitting their subjects into three groups: one that ate a breakfast of porridge made with milk and cycled for 60 minutes two hours afterwards, one that ate the same breakfast, but rested for three hours instead of working out, and one that exercised without eating breakfast.
What Does This Study Mean for Runners?
By testing the participants’ blood glucose levels after they worked out or rested, the researchers found that eating breakfast “increased the rate at which the body burned carbohydrates during exercise, as well as increasing the rate the body digested and metabolized food eaten after exercise, too,” according to a press release.
Translation? Burning carbs can give your endurance performance a serious boost, according to Javier Gonzalez, Ph.D., senior lecturer at the university’s Department for Health and coauthor of the study.
“Carbohydrate is a relatively fast fuel, since energy can be generated twice as quickly than when fat is used as a fuel,” he told Runner’s World via email. “That is part of the reason why when we ‘hit the wall’ and run out of our glycogen stores, we have to slow down our running pace to a level where fat can supply the energy.”
If you’re not eating breakfast, your body burns fat as fuel instead of carb stores. But when this happens, it takes twice the energy, which slows you down, according to Gonzalez.
Related: Smash your goals with a Runner’s World Training Plan, designed for any speed and any distance.
Another way carbs help your running is because they’re an oxygen-efficient fuel, which means that burning carbs as fuel requires 10 percent less oxygen than burning fat as fuel, Gonzalez says. That’s more oxygen available to help you breathe.
But don’t worry if porridge isn’t your jam. Gonzalez says that as long as you’re eating a meal similar in size and nutrients (carbs with a bit of protein) about one to four hours before your run, you’ll be good to go. Try something like oatmeal paired with yogurt or topped with a sliced banana. Just don’t go too crazy with fat and fiber—fat takes too long to digest, and fiber can mess with your digestive system.
Should You Still Eat Breakfast Even If You’re Not Working Out?
Fueling your morning isn’t just useful when it comes to running. According to Gonzalez, “there is some evidence that breakfast consumption can assist with concentration,” so eating when you wake up on off days can benefit you at work or at school, too.
The Bottom Line
While this study was indeed limited—only 12 men participated—“there is no reason to believe the responses would be drastically different [in females],” Gonzalez says. So if you want to run at your best, breakfast is definitely an important factor to consider.