Pre-Run Fueling Guidelines

by Diane Cressey, certified Specialist in Performance Nutrition

I am often asked by runners what they should eat before a run. This depends on many factors, such as what distance you are running, timing of food intake prior to a run to eat and individual tolerances. Since training runs lasting more than 60 minutes are much more complex, for now I will address distances of 60 minutes or less.

If you’re running 5k to 10k events or training runs lasting less than 60 minutes, you will not significantly challenge muscle glycogen stores, therefore, carbohydrate loading is not recommended. What you should do, however, is to eat properly in the 24 to 48 hours before your training run or event. Nutrient ratios should fall in the following range of total calories consumed during this time period: 20-25% protein, 55-60% carbohydrates, and 20% fat. Water intake is also important.

Pre-run routine

If you’re a morning runner, your pre-run nutrient intake depends on how much time between waking and running. While some runners can easily tolerate running on an empty stomach for runs of 60 minutes or less, others who may be carbohydrate sensitive or hypoglycemic may need to consume carbohydrates to maintain blood glucose levels since liver glycogen stores are low in the morning hours after waking.

Eating too close to training or racing is the biggest mistake most runners make as this can cause stomach upset as well as bloating, cramping and diarrhea. Proper timing helps to stabilize blood glucose levels and feeling good during the run.

One hour prior to run

Most runners who train in the early morning usually do not have hours prior to a run to properly digest solid food. In this case, one hour prior to run, consume ½ gram per pound of easily digestible carbohydrates in liquid or gel form (avoid fiber, protein and fat). For example, a 150-pound person would consume approximately 75 grams of carbohydrates. Protein and fat slow digestion, therefore you would still be digesting the food you ate while you’re running, which can give you a heavy feeling, moreover, these nutrients will not be available for use as fuel for short runs. Fiber may cause intestinal distress and the need to eliminate during the run. Solid food may be consumed if tolerated; quick-digesting, high-glycemic food choices are best. Easy choices are sports drinks and gels.

Two hours prior to run

The focus is still carbohydrates. Now you can consume up to 1 gram per pound of body weight. Therefore, a 150 pound person can consume up to150 grams of carbs. A minimal amount of protein and fat may be tolerated. Again, stick with higher-glycemic food choices.

Three to four hours prior to run

Moderate amounts of low-fat protein and a small amount of fat may be consumed three to four hours prior to a run since there is more time for digestion. Increase carbohydrates consumed to 1.5 to 2 grams/lb weight. Low fiber is still recommended. Nutrient ratio should be approximately 10-15% fat, 10-15% protein and 70-80%% carbohydrates. Moderate to high-glycemic carbohydrates are recommended.

If your last meal consumed is three to four hours prior to run, consume approximately 90 calories of a sports drink or gel with 8 oz water approximately 15 minutes prior to run to help stave off hunger and stabilize blood sugar during the run.

Mid-day or evening runners should follow guidelines above.

Importance of Water

Drink ½ your body weight in fluid oz daily. Replace water lost through sweat. Urination should occur every 1.5 to 2 hours.

Dehydration will impair performance

Dehydration will elevate heart rate.

Temperature regulation is controlled by water.

Blood is 90% water and is responsible for transporting nutrients and energy to working muscles and than transporting metabolic waste away from tissues. Dehydration causes the blood to thicken and deliver less oxygen to the brain and muscles.

Water lubricates joints and aids in digestion.

Water helps recovery.

Water intake guidelines

Prior to runs

2 hours before run – drink 16 – 24 oz of water

15 - 30 minutes before run – 8 – 16 oz water

The above water timing intake will prevent the need for elimination during the run.

During runs

Only water is necessary during 5k and 10k events. Drink 4oz every 15 minutes.

Post exercise

Re-hydrate!

Eat normally after a short run. 20-25% protein, 55-60% carbohydrates, and 20% fat of total calories.