Eating and Running | How Long Should I Wait to Workout After Eating? – Runner’s World

At some point during your running career, you’ll come across traditional advice to avoid eating a large meal before a run and opting for a small snack of 200 to 300 calories instead. While it’s important to know how much you should eat before running, it’s just as important to know how long you should wait to run after eating.

First, lets define a “large meal” as a meal containing more than 600 calories with several ounces of protein or meat, carbohydrates, and some fat—a typical lunch or a large breakfast. If you have a meal like this, you should wait three to four hours before running so that your body can digest this type of food.

Digestion requires a rather large amount of the body’s energy. To facilitate the digestion process, the body directs more blood flow to the stomach and other internal organs to accomplish this work—which is also the reason we often feel sleepy following a large meal. The increased blood flow to internal organs means less blood flow is available to our large muscle groups, such as our legs and arms. When we exercise, the opposite occurs; blood flow is redirected from internal organs to the large working muscles to provide the necessary energy for muscle contraction.

When we have a large amount of food in our stomach, running is difficult or uncomfortable because our body is simply not designed to do both digestion and exercise at the same time. Stomach cramps, stomach aches, or gastrointestinal (GI) distress are the most common complaints when trying to run on a full stomach. The mechanical mixing and jostling that naturally occurs while running can upset the digestive tract too.

When it comes to smaller meals or snacks (think: 200 to 300 calories), you may only need to wait an hour or two before your body is able to digest. If your snack is made up of simple carbohydrates and little or no fat and protein like a banana and an english muffin with jam, an hour or so should do as these simple carbs are easier to digest. If you introduce more fat and protein like a cup of yogurt and a slice of toast with peanut butter, it’s best to wait a bit longer.

That said, certain runs (under 60 minutes at a moderate effort) don’t require any food at all and some athletes are able to just eat and run. Some endurance athletes even train their bodies to eat on the run. Even at the marathon distance, runners must ingest some nutrition during the race, although hardly a large meal. Experimenting in your training with eating and running will let you know just how much you are able to eat (or not eat) before a run.

For the best training results though, allow three to four hours after eating a large meal before running, especially if the workout calls for some intensity. For small snacks and quick bites, give yourself about an hour or two to digest before pounding the pavement.