What you should know before you hit the gym or the trails in the morning.
“This is the first study to show that breakfast speeds up the clearance of glucose out of the bloodstream and into muscle after we eat lunch, even when we perform exercise in-between breakfast and lunch,” Javier Gonzalez, PhD, co-author, and senior lecturer at the Department for Health at the University of Bath in the U.K, told Healthline.
What did the study find?
Researchers led by a team at the University of Bath looked at 12 male adults who ate porridge with milk two hours before cycling for an hour, and compared it to those who fasted overnight before the ride. They found that those who ate boosted the rate at which they burned carbs during the workout. Those who ate also increased the rate that their bodies digested and metabolized food after a workout as well.
“We found that, compared to skipping breakfast, eating breakfast before exercise increases the speed at which we digest, absorb, and metabolize carbohydrates that we may eat after exercise,” Gonzalez said in a statement.
The study was published last month in American Journal of Physiology: Endocrinology and Metabolism.
Researchers said that the carbs burned during exercise were not just coming from the breakfast eaten — but also from the carbs stored in muscles as glycogen. This increase in the use of muscle glycogen may explain why there was more rapid clearance of blood sugar after lunch when breakfast had been eaten before exercise, he said. Gonzalez noted that previous research found rest and eating breakfast can alter the way we metabolize lunch.
Eating a breakfast high in fat, protein, or carbs would likely produce a different response, Gonzalez explained. Research has shown that a high-fat breakfast impairs blood glucose control at lunch time, which is the opposite response to eating a high-carb or high-protein breakfast. Most of the research on that was conducted when people rested afterwards, not when they exercised.
Gonzalez noted that the study was small but tightly controlled.
Both Gonzalez and outside researchers would like to find out more about the effects of fasting and eating with regards to working out on other populations, such as women, or those who are overweight and obese.
“More research is necessary before we can make definitive conclusions regarding the impact of eating before exercise has on health outcomes and our physical well-being,” Rachel Stahl, RD, a registered dietitian from New York City, told Healthline.
What to eat, when to eat
Lizzy Swick, RDN, a nutritionist from New Jersey, noted that skipping breakfast can have positive effects on insulin levels, blood sugar control, weight, energy levels, and inflammation for some people.
But she noted that everyone is different.
“While the science is clear that it might help with certain populations of people, there is no one-size-fits-all approach to nutrition, so I don’t advise this for everyone,” Swick said.
For people who want or need breakfast, she recommends eating a protein- and fat-based meal within one hour of waking up.
Keeping breakfasts heavier on healthy fats and protein and saving carbohydrate-rich foods like starchy vegetables, grains, legumes, and fruits for later in the day is beneficial to keep blood sugar and insulin levels lower for more of the day, she added. It can control appetite, curb cravings, and better control cortisol patterns. That can include eggs with some non-starchy vegetables and some avocado, or having whole-fat yogurt with chia or flax seeds and low-glycemic berries. People can also try a green smoothie, but don’t add honey or sugary fruits such as mango or banana.
Pea, whey, and collagen are good protein add-ins.
Instead of breakfast, you can also try a snack before working out, such as half a banana with almond or peanut butter on it, or a handful of nuts.
“Whether you are eating or not before a workout, aim to have a balanced meal or snack that contains protein within 30 to 60 minutes post-exercise,” Swick said. “Low-level aerobic activity like walking before breakfast can tap into your ‘fat-burning zone’ and boost your fat burn, and you might feel better saving more intense workouts for later in the day, if your schedule permits.”
Consume the snack or meal 45 minutes before exercising, whatever you eat, so the body has time to digest the food, Stahl added.
“If your exercise routine is lighter in intensity and less than an hour, you may want to eat a smaller amount,” she said.
A good breakfast can include oatmeal, a nut butter, and a fruit. Just make sure you use plain oats — not the sugar-laden varieties. Swap in quinoa instead of oats if you prefer that.
“I love this combo because oatmeal contains complex carbs for sustained energy, nut butter for a healthy dose of protein and heart-healthy monounsaturated and polyunsaturated fats, and banana for a kick of instant energy as well as key vitamins, minerals, and antioxidants,” she said.
Scrambled eggs with a veggie and avocado, or plain Greek yogurt with chia or flax seeds, along with berries, are other smart options.
“If you plan on working out first thing in the morning and are looking for a healthy breakfast, I would recommend a smaller portion of the above ideas, or a snack consisting of a balance of carbohydrates, healthy fat, and protein,” Swick said.
Smart eating is best
Dr. J. Michael Gonzalez-Campoy, medical director and CEO of the Minnesota Center for Obesity, Metabolism and Endocrinology, said this study adds more evidence that three well-balanced meals a day — including breakfast — is good for our health.
Those meals should include a protein, carb, and fat, he said. It also opens the door for more research to further understand the mechanisms behind how the body behaves differently when a person has, or has not, eaten breakfast. The findings need to be replicated on other populations, such as those with obesity, to see if the same results hold true.
“The message that is emerging from this and other studies, is that limiting the total daily number of calories is key to good health, but the distribution of these calories during the day is extremely important,” Gonzalez-Campoy noted.