How to Properly Fuel Before a Long Workout

Eating too much too close to training or competition for your own personal tolerances is probably the biggest nutritional mistake that you can make as a runner. Because running jostles your gastrointestinal system, GI disturbance is a more common problem in running than in other endurance sports. Timing your pre-exercise meals is important for feeling “light” during your run and avoiding unpleasant symptoms such as a sloshing stomach, bloating, cramping, and diarrhea.

Prior to a short, relatively easy run, what you eat before training may simply be a matter of comfort and fending off hunger or hypoglycemia. It is not uncommon for runners to train in the early-morning hours. Some experiment and find that having something light, such as juice and a plain piece of toast, works best at this time. Regardless of your tolerances, make sure that you drink water or even a sports drink to hydrate. On long morning runs, consider taking a fluid bottle or fluid belt with you.

Consuming a sports drink maintains blood glucose levels in the latter part of a longer run, but even on shorter runs it is good practice. It prepares you for longer races, and it helps in any run that occurs after you have not eaten for several hours, whatever the time of day. Consuming regular meals and snacks replenishes your fluctuating liver glycogen stores and consequently helps maintain steady blood glucose levels throughout the day and during training.

For afternoon or evening runs, try to time your meals carefully and eat 3 or more hours before running. Leave enough space between meal or snack times and training times, especially for high-intensity runs and speed work. Emphasize carbohydrate sources that are easily digested. You may want to consider a liquid sports supplement, a meal-replacement product, or an easily digested gel before longer training sessions. Real food products also work well if you have experimented and determined your own tolerances.

Fueling for the Long Run

Experiment with pre-race eating before your long weekend run. This practice sets the stage for race day—it is particularly important to know your tolerances and preferences when racing a distance of 10 miles (16K) or longer. Although it may be tempting to sleep as late as possible before a long early-morning run, the pre-exercise meal is necessary for filling both liver and muscle glycogen stores. Liquid meals may work best, but you can also experiment with carbohydrate foods that are low in fiber. Knowing what works for you in training will help lighten pre-race nerves and help you feel more comfortable about your nutritional choices on the big day.

Ideally, take in as much carbohydrate as you can tolerate up to 1 gram per pound (about 2 g/kg) of body weight 2 hours before the long training run. Although you may leave a longer time interval after eating before a race start, this is still essential practice for having a quality and well-fueled long run. If you decide to eat even closer to the long training run, lower your carbohydrate intake to half a gram per pound (about 1 g/kg) of body weight. Food choices should be kept simple. Two hours prior to a long run, a 160-pound (73 kg) runner could consume more than 100 grams of carbohydrates from 2 slices of toast topped with 2 tablespoons (40 ml) of jam, plus 12 ounces (360 ml) of orange juice. After this meal and leading up to the run, 24 ounces (960 ml) of a sports drink would provide an additional 40 grams of carbohydrate or more.

Some simple morning noshes that sit easy in your stomach and pick up your run include:

• 1⁄2 bagel with 1 tsp. (8 ml) peanut butter and 1 tbsp. (20 ml) jam with 8 oz. (240 ml) juice
• 1⁄2 cup instant oatmeal with 4 oz. soy milk and 1 tbsp. (20 ml) raisins
• 1 medium-sized high-carbohydrate energy bar and 1 banana
• Pretzels and hummus with a glass of juice 
• Liquid meal replacement
• Crackers with a nut spread and banana
• Smoothie with milk, yogurt, and fruit
• Tortilla with peanut butter and raisins
• Chocolate milk and grapes
• Toasted waffle with syrup and fruit
• Bowl of rice and juice

Of course, coffee or tea, or a glass of water, can be included with all of these suggestions. Even with a good morning carbohydrate boost, longer or higher-intensity morning runs may call for use of sports drinks. Experiment with pre-run foods and fluids, as well as with water or sports drinks during your run, to determine what provides the best energy boost within your tolerances.

This article is an excerpt from Sports Nutrition for Endurance Athletes by Monique Ryan MS, RD, LDN, CSSD. In her comprehensive guide to sports nutrition, Ryan uses her 30 years of experience coaching professional and age-group athletes to simplify this complex subject into proven, real-world guidelines.