This Is Exactly How Long You Should Wait to Run After Eating a Meal

If you've ever gone out for a run shortly after a meal, you probably know that running on a full stomach can be uncomfortable. Simply put, your body isn't designed to digest food and exercise simultaneously. You need to give your body the time it requires to break down food properly before lacing up your shoes for a workout.

How much time you need between when you eat and run depends on a few key factors.

There is no scientific evidence that running (or participating in any vigorous exercise) after eating is dangerous to your health. So, does that mean you can run on a full stomach? Yes. The question is, do you want to run on a full stomach? The answer is, probably not.

The problem is that both digestion and exercise require increased blood flow. After eating, blood flow is directed to the internal organs, primarily the digestive organs, so that your body can process food. Studies suggest that this increase in blood flow reaches its maximum after 20 to 40 minutes and lasts for about one and a half to two hours.

But when you start to exercise, that blood flow is diverted to your working muscles to deliver the oxygen and fuel that they need. This leaves your digestive organs without the blood flow that they need to process food.

According to a 2017 position statement published by the International Society of Sports Nutrition (ISSN), eating shortly before exercise can overwhelm the digestive system and potentially lead to cramping and discomfort once exercise begins. You may also experience bloating, nausea or sluggishness if you run after you eat.

Since this is a common issue, there are a few popular and highly generalised rules that are widely repeated in running circles regarding running after a meal. The guidelines depend on the size of the meal you consume.

• After a large meal (usually about 600 calories or more), wait 3–4 hours before running
• After a small meal (usually about 300–400 calories), wait 1–2 hours before running
• After a snack (usually 100–200 calories), wait about an hour before running

While these are smart rules to use as a starting point, not every runner should adhere to them. The ISSN guidelines and previous research generally support these ideas, but study authors are often quick to point out that pre-exercise meal timing should be tailored to the individual athlete because each person's tolerance is different.

Some seasoned runners can eat a large meal and run an hour later, while others need more than four hours to digest a big meal. To determine the timing routine that works best for your body, consider a few key variables.

Nutrition experts say that different macronutrients take different amounts of time to digest.

• Simple carbohydrates take the least amount of time to digest. Table sugar, honey and maple syrup contain simple carbohydrates. Foods such as fruit and dairy products also contain some simple carbs along with other nutrients.
• Complex carbohydrates, such as grains, root vegetables, beans and bread, take longer to digest than simple carbs but not as long as protein or fat.
• Protein foods, including eggs, meat, poultry and plant-based sources such as tofu, are made up of amino acids and are more complex. They require more time to digest than carbs, but not as much time as fat.
• Fat is the slowest source of energy. Fatty foods such as oils and butter take the longest amount of time to digest.

You can use this information to plan when to eat meals and snacks before a running workout. For instance, if you plan to have a big lunch and then run immediately before dinner, you may want to eat a meal that takes slightly longer to digest so you still have enough energy a few hours later when it is time for your body to perform. For instance, for lunch you might eat brown rice (complex carbs) with tofu (protein) cooked in a small amount of oil (fat).

But if you need to grab a quick snack shortly before a run, you'll want to eat a small amount of food that digests quickly. Foods that provide simple carbs, such as a banana, can provide energy without discomfort from delayed digestion.

You don't want to overdo it with carbs before a running workout, however. Research cited in the 2017 ISSN position suggests that excessive carbohydrate consumption, in particular fructose (sugar from fruit), in the initial hours before exercise may negatively impact exercise performance possibly due to sharp changes in blood glucose levels.

Depending on the distance and intensity level of your run, you may not need a lot of fuel to perform at your best. In some cases, eating a meal or even a snack may not be warranted.

For instance, if you plan to run an easy three miles in the late morning and you ate a light, balanced breakfast a few hours ago, there is probably no need to fuel up with a snack or another meal before running. And if there is a chance that the snack may cause gastrointestinal cramps, then it may not be worth taking the risk.

On the other hand, if you have a longer, harder workout in the late afternoon, then you should plan to fuel up with plenty of carbs, protein and fat so that your body has the energy it needs to perform well. In that situation, you should plan to wait a few hours after the meal to digest it properly. You can use the basic rules as a general guideline, but you should also use your previous experience with meal timing to make adjustments as needed.

The last—and most important—factor to bear in mind is your own personal tolerance. Everybody digests food differently. While some runners can comfortably run after eating, others have to wait a substantial amount of time or suffer the consequences.

The smartest approach is to use the general guidelines as your starting point. Be cautious about running too soon after eating a big meal. Shortly before running, stick to foods that are made up mostly of simple carbs and keep portion sizes small. Be mindful of how your body responds to different foods or different wait times.

If you feel the need to change your nutrient timing, do so gradually. Make small tweaks to your diet and workout schedule to fine-tune the best plan for you. Most importantly, if you have a big race, stick to the timing routine that you've used during training. You don't want any big surprises during the event. With some trial and error, you'll find the best schedule based on your own personal needs and lifestyle.

For more expert-backed nutrition tips, be sure to download the Nike Training Club App!