Eating before exercising is often recommended to top off your energy stores.
However, some people may experience side effects when eating too close to exercising.
These can usually be avoided by allowing sufficient time for digestion, though this time period varies by the type of exercise.
This article explores how long you should wait to exercise after eating.
When to exercise after eating
When consuming a meal, food enters your stomach and is slowly processed and released into your small intestine in small amounts.
Food generally takes 2–4 hours to move from your stomach to your small intestine completely.
While it’s usually unnecessary to wait until the food is fully digested before exercising, it’s best to give it some time to settle in your stomach.
For most people, 1–2 hours is sufficient after a moderate-sized meal, while waiting at least 30 minutes after a snack is okay.
At that point, food has been digested enough to avoid stomach upset. That said, as the intensity of the exercise increases, so does the risk of side effects.
Summary: While it generally takes 2–4 hours to fully digest a meal, waiting 1–2 hours after a moderate-sized meal and 30 minutes after having a snack should be sufficient before exercising to avoid side effects.
Food volume and type
Regarding eating before exercise, meal size and composition play a significant role.
The larger the meal you eat, the longer it will take to digest, increasing the time you should wait before exercising.
In addition, the composition of the meal affects digestion time.
Meals higher in fat, protein, and fiber tend to be digested slower than those containing a more significant proportion of simple carbs and more processed proteins, such as those found in some protein shakes and supplements.
High protein foods include intact animal proteins such as beef, pork, chicken, and fish.
Thus, it’s best to avoid eating large meals high in fat, protein, and fiber shortly before exercising to avoid any potential adverse side effects.
Summary: Meal size and food composition affect the rate of digestion, so it’s best to avoid large meals high in fat, protein, and fiber shortly before exercising.
Potential side effects
While the side effects of eating close to a workout are highly individual, the most common ones are digestive symptoms and performance issues.
Exercise after eating may cause digestive symptoms
Eating too close to working out may cause some digestive discomforts. The most common ones include:
Data suggests that endurance athletes like runners and cyclists are at the highest risk of experiencing these side effects due to the nature of their sport.
Lower-intensity sports such as golf, walking, and archery are much less likely to trigger digestive symptoms.
Furthermore, most of these side effects can be avoided by allowing some time for digestion before training.
Usually, 1–2 hours is sufficient after a moderate-sized meal, while waiting at least 30 minutes after a snack is okay.
Exercise after eating may affect your performance
While fueling up for an intense training session is essential, eating too close to a workout may harm your performance.
Athletes and recreational gym-goers often experience a feeling of sluggishness when exercising right after a meal.
A small study of 10 male basketball players found that several experienced nausea, belching, and stomach bloating when a protein and carb meal was consumed before training, compared with eating a high-carb meal without protein.
These symptoms may hinder performance when participating in your sport or exercise.
Summary: Some people may experience various side effects when exercising shortly after eating. These include bloating, nausea, cramping, reflux, vomiting, diarrhea, sluggishness, and potentially hindered performance.
How long should you wait?
The amount of time required to avoid digestive side effects varies by individual and the sport.
Suggested read: Top 10 health benefits of regular exercise
While data on the specific amount of time you should wait is limited, here are some general recommendations:
- Cross-country skiing: 1–2 hours
- Crossfit: 2–3 hours
- Cycling: 2–3 hours
- Downhill skiing: 1 hour
- Golfing: 1 hour
- Mountain biking: 1–2 hours
- Running: 2–3 hours
- Swimming: 2–3 hours
- Walking: minimal time
- Weight training: 1–2 hours
Some endurance sports, such as running, cycling, and cross-country skiing, lasting over an hour may require eating while exercising to maintain energy stores.
In this case, it’s best to stick to fast-digesting carbs like energy gels or chews to prevent any digestive side effects.
You may find that you can comfortably train shortly after eating, or on the contrary, you may require waiting several hours to avoid side effects.
Therefore, you should experiment to determine your ideal digestion period before exercising.
Summary: The length of time you should wait before exercising varies by sport and individual. Thus, you may have to experiment to find your ideal digestion period. Commonly, it ranges from 1 to 3 hours.
To optimize your energy stores, eating something before exercising is generally recommended.
Some may experience adverse side effects when eating too close to a workout.
For most people, waiting 1–2 hours to exercise after a meal and at least 30 minutes after a snack is sufficient to avoid side effects.
Those practicing endurance sports may want to wait longer and need to incorporate fast-digesting carbs during workouts lasting longer than 1 hour.
Lastly, avoiding large meals containing high fat, protein, and fiber will help lower the risk of adverse side effects.