"Priming" Study Offers New Wisdom on Eating Breakfast Before a Workout

To eat or not to eat? A new take on the "window of opportunity."

The field of sports physiology has a complicated relationship with breakfast. Some love it, claiming it’s a way to get going and give the body some physiological quick fuel before the gun goes off. Others dread the feeling of food sitting undigested in the stomach during a hard effort. If you fall into the second category, a new study in American Journal of Physiology: Endocrinology and Metabolism suggests that you might want to suffer through the gastric agony. The results show that the benefits of eating breakfast might last far after the race is over.

The study, conducted at the University of Bath in the UK and led by Javier Gonzalez, Ph.D., was conducted on 12 men who were first given porridge before engaging in a grueling hour of cycling. Then, after a suitable amount of recovery, the same men fasted through the night and then hopped back on the bikes. When Gonzalez ran blood tests on the men at the conclusion of each test, he noticed something odd about the way their bodies were burning through fuel when they ate their post-workout meal. On breakfast days, they were processing the food at faster rate than on non-breakfast days.

“When you eat a meal, the carbohydrate from that meal will eventually enter the blood before being disposed of into tissues, mostly [into] skeletal muscle,” Gonzalez tells Inverse. “We showed that if you eat breakfast before exercise, you have a higher rate of carbohydrate entering the blood at meals consumed after exercise, but also a higher rate of carbohydrate leaving the blood into the muscles.”

A cycling test was conducted  to measure the effects of breakfast "priming" on 12 British athletes 

Javier Gonzalez

Gonzales’ results are interesting for anyone who may have noticed pro athletes scrambling for “recovery drinks” minutes after they cross the finish line. For moderate- to high-intensity efforts — Gonzales lists sprints as an example — the body burns through stores of glycogen stored in muscle in attempt to manufacture quick energy. But these stores are depleted after exercise, so many athletes try to artificially get glucose back in their system to help jumpstart the recovery process.

Some researchers have called this period of refueling the “anabolic window,” referring to a period of time when the body might be more receptive to absorbing these carbohydrates. But experts in the field tend to fluctuate on whether the timing of nutrients post-workout is really that important, and Gonzales is quick to point out that many studies in this area studies are usually done on fasted athletes, which is what makes his research uniquely useful.

Interestingly, Gonzalez’s results indicate that there does appear to be some of period of rapid nutritional storage after exercise but that your body might need some help opening up that window. Eating breakfast, it seems, may be a way of “priming” the body to do so by warming up certain signaling pathways that tell muscles to store glucose for later use.

“We think the higher rate of glucose disposal into muscle is because signalling pathways in the muscle are activated to a greater extent when you have had breakfast before exercise, compared to fasting,” he says. “These pathways activate specific transport proteins that transport carbohydrates from the blood into muscle.”

Initially, he explains that eating breakfast before exercising can increase blood flow to the gut, which is likely higher during and after exercise if you’ve made your body digest something beforehand. It’s this increased blood flow which begins the process of getting these transport proteins ready to go.

These results come is a pretty small group of athletes , so more studies will have to be done before this prompts any big changes in the field. But while the jury is debates the existence of an anabolic window, it seems that for the time being, eating breakfast pre-workout might be a solid bet.

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