Eating before Exercising: Is Carb Loading Necessary?

Finding the right balance for exercise and timing of food intake

By Michael Ormsbee, PhDFlorida State University
Edited by Kate Findley and proofread by Angela Shoemaker, Wondrium Daily

Nutrient timing, which is when you eat, can be used to optimize body composition. Professor Ormsbee explains how to apply this concept to your pre-exercise routine.

Man preparing pre workout meal
Key to what nutritional energy supply your body will need before a workout is the intensity, duration, and type of workout that you will be doing. Photo by By Jacob Lund / Shutterstock

What to Eat before Exercising

If you’re like most people, then you probably wonder what to eat before or after your workout, or if you should be sipping a sports drink at the gym. The timing of when to eat our meals around exercise sessions is important for many reasons. 

We need energy to fuel our workouts—perhaps even multiple bouts of exercise in one day. At the same time, we don’t want to eat too much or too close to a training session or we may experience gastrointestinal issues that could ruin a workout. Exercise can be tough enough as it is, so you don’t want additional issues.

Keeping this point in mind, your body needs at least some fuel in the tank to perform optimally. Glycogen, which is the storage form of carbohydrates in the body, is the main fuel source during moderate to vigorous exercise, so it stands to reason that carbohydrates are an important nutrient to eat before exercise.

These energy stores are sometimes the limiting factor in exercise, and running out can be the cause for “bonking” or “hitting the wall,” as many long-distance exercisers can tell you. Essentially, you run out of fuel and your tank is empty. 

Carb Loading for Athletes

Thus, it is recommended that consuming carbohydrates prior to exercise will fill up the tank. This is usually referred to as carbohydrate loading

How much, though? It depends on your purpose and what level of activity you are doing.

“Recently, I was in Tennessee to watch the Ironman Chattanooga, an event where athletes swim 2.4 miles, bike 112 miles, and then run 26.2 miles—an amazing feat,” Professor Ormsbee said. “Is carbohydrate loading important to these athletes? You bet it is.” 

Most of these athletes compete at a high intensity for anywhere between 8–14 hours continuously. Thus, not only is pre-exercise an important nutrition component, but so is during and post-exercise nutrition. 

During these races, athletes depend upon sports drinks and gels, pre-made sandwiches, and all sorts of foods that the athlete can eat without getting an upset stomach, and that they can carry with them while riding a bike or running. No wonder nutrition is considered the fourth event along with swimming, biking, and running for triathletes.

Many leading sports nutritionists instruct these athletes to increase their carbohydrate consumption to about 70% of their diet five to seven days before a competition, by adding things like oatmeal, rice, pasta, and bread to almost every meal. However, does this really apply to the average person? 

Pre-Exercise Nutrition Made Simple

To answer that, ask yourself if you exercise that much. Chances are that you don’t, and there’s certainly nothing wrong with that. 

These athletes are exercising anywhere from 10–20 or more hours per week. How should you change your pre-exercise nutrition if this carbohydrate loading isn’t necessary for your average 30-minute jog or spin class at the gym every Tuesday?

According to Professor Ormsbee, the details of optimal pre-exercise nutritional strategies are less important to the average person. That’s not to say that pre-exercise nutrition is not important, but simply consuming some good nutrition sources with carbohydrates and protein is all he would suggest concentrating on. 

“I see time and time again, people making the relationship between exercise and nutrition much more difficult that it really needs to be,” Professor Ormsbee said. “In my experience with sports nutrition consulting, I have seen the greatest results in performance and body composition changes when things are simplified—and this crosses over all types of clients I’ve worked with—from age-group triathletes to Olympians.”

These healthy sources of carbohydrate and protein should come ideally three or four hours before exercise. Be conscious of total calories that you are taking in and burning during exercise so that you don’t end up overeating, or adding too much to your total caloric intake, and ultimately hurting your body composition or performance goals. 

You could simply eat two eggs and a banana or have a glass of milk. Also, many people prefer to work out in the morning before they eat breakfast. If that’s you, and you like that, then go for it. However, if you work out for more than 90 minutes, or at a vigorous intensity, you might consider fueling up a little and seeing how it makes you feel.

This article was edited by Kate Findley, Writer for Wondrium Daily, and proofread by Angela Shoemaker, Proofreader and Copy Editor for Wondrium Daily.
Dr. Ormsbee is an Associate Professor in the Department of Nutrition, Food, and Exercise Sciences and Interim Director of the Institute of Sports Sciences and Medicine in the College of Human Sciences at Florida State University.

Michael Ormsbee is an Associate Professor in the Department of Nutrition, Food, and Exercise Sciences and Interim Director of the Institute of Sports Sciences and Medicine in the College of Human Sciences at Florida State University. He received his MS in Exercise Physiology from South Dakota State University and his PhD in Bioenergetics from East Carolina University.