Natalie Digate Muth by Natalie Digate Muth

Food and ExerciseIt’s the age-old question – what (and when) to eat to set the stage for a great workout and optimal performance without nagging abdominal pains, hunger pangs, and premature exhaustion?

Avoiding GI distress before and during a workout or race is a matter of being smart about what and when you eat. First, never ever try out a new food on race day.  Experiment before the big event to find what works for you.

When you exercise, blood flow is diverted away from your digestive system to your muscles. So right before working out you should avoid large meals and foods that your body has to work harder to digest, like fats, protein and fiber.  In general, you should eat about three hours before working out to give your system a chance to move the food out of the stomach and begin digestion and absorption. For early morning workouts, eat a small amount of a rapidly digestible carbohydrate like a slice of bread or a banana when you wake up (aim for about 30 minutes before you begin your workout).  If you exercise in the afternoon or evening, you may also want to have a light snack right before, especially if it’s been more than three hours since you’ve last eaten.

For workouts lasting longer than an hour you’ll need to replenish the energy you’re burning. Since solid food is not an option for most people sports drinks and gels are usually your best bet. Everyone reacts differently to different brands of drinks and gels (some can’t even stomach gels), so trial and error is key.  Drinking large volumes of fluid helps to speed gastric emptying but can also cause cramping, especially if consumed all at once. Instead, try taking small amounts of fluid every 15 to 20 minutes.

For optimal recovery after an endurance workout, it is important to eat carbohydrates to replace the stored energy (glycogen) that was used up doing the workout. For best results, the American Dietetic Association recommends aiming to eat about 1.5g carbohydrate/kg body weight within 30 minutes of finishing the workout and then every two hours for four to six hours.  A little bit of protein will also help to repair muscles – this is especially important after a resistance training workout.  Of course the amount of refueling needed depends on the intensity and duration of the workout.

For more information check out the joint position paper of the American Dietetic Association and the American College of Sports Medicine.


Natalie Digate Muth, MD, MPH, RD, is a registered dietitian and recent graduate of the UNC School of Medicine. She is an ACE-certified Personal Trainer and Group Fitness Instructor, and holds additional certifications with the American College of Sports Medicine and the National Strength and Conditioning Association. She has made several appearances as a nutrition expert on CW's San Diego 6, been quoted as a fitness expert in the New York Times and other newspapers and is an ACE Master Trainer and award-winning author. She is currently a pediatrics intern at UCLA Mattel Children’s Hospital.