Exercise after eating is primarily a personal preference. While getting enough of the right macronutrients before a workout is crucial, digestion is also important. You want to eat close enough to your workout that you have enough energy, but not so close that you experience an upset stomach. The latter factor largely depends on your own body. What you eat before a workout determines not only how soon you can exercise, but also how well you perform.
The best time to eat a meal is two to four hours before your workout.
It's All About Digestion
If you get to the gym right after eating a big meal, your body hasn't had time to process the food you've just consumed. A light snack may not cause you much trouble, but a big meal too soon might affect your performance, according to registered dietitian Christopher R. Mohr.
Some people have stomachs of steel and can work out on a full stomach without problems. Others have more sensitive stomachs and might experience stomach pain, nausea or other gastrointestinal problems if they eat too soon before a workout. Sports nutritionist Molly Kimball told ABC News that people need to experiment with pre-workout nutrition to see what works best for them.
Keeping It in the Window
You don't want to wait too long after you eat to work out. The carbs and protein you just ate play roles in how much energy you have to exercise, how effective your workout will be and how well you'll recover after your workout.
Working out on an empty stomach leaves you low on fuel. Without enough carbohydrates, which are the body's main source of energy during exercise, you may feel sluggish and have low energy. Working out on an empty stomach can also cause a drastic drop in blood sugar, which can leave you feeling lightheaded and nauseated, according to PartnerMD.
If you are a weightlifter or bodybuilder, your protein needs increase. You should be eating protein throughout the day, but especially in the period before and after your workout. Protein, which is important for recovery, is what builds muscle.
For the Long Haul
In certain situations, you might need to eat during your workout. For example, if you're training for a half-marathon, some of your training runs are likely to be long. If exercise last more than one hour, registered dietitian Lee Murphy recommends eating 30 to 60 grams of carbohydrate from either easily digestible foods like bread and bananas or from sports drinks. According to Brian St. Pierre of Precision Nutrition, bodybuilders may need to consume a protein and carbohydrate drink during their workout.
Good Pre-Workout Snacks
Two to three hours before your workout, St. Pierre recommends a meal containing carbohydrates, protein and fats. Eat equal portions of a protein, such as fish or lean chicken, and vegetables and have one or two servings of carbohydrate-dense foods, such as brown rice and fruit. You can also include a small portion of healthy fats from nuts or oils.
Within one hour of your workout, St. Pierre says a shake is your best bet because it will digest more quickly. His favorite recipe includes a scoop of chocolate protein powder, a fist-full of spinach, a banana, a tablespoon of nut butter and 8 ounces of unsweetened almond milk.
- ABC News: How Soon After Eating a Meal Can I Exercise?
- Academy of Nutrition and Dietetics: Timing Your Pre- and Post-Workout Nutrition
- PartnerMD: Is Working Out On an Empty Stomach Good for You?
- The Weston A. Price Foundation: Digestion and Absorption of Food Fats
- The Physician and Sports Medicine: Protein for exercise and recovery.
- American Fitness: CEU Corner: Nutrition & Exercise - Timing is Everything
- Precision Nutrition: Workout nutrition explained.
- SportMedBC: Carbohydrate Power: A prime fuel for sustaining energy during exercise