It’s often recommended to eat before exercising to top off your energy stores.

However, some people may experience side effects when eating too close to exercising.

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.

It generally takes 2–4 hours for food to completely move from your stomach to your small intestine.

For most people, 1–2 hours is sufficient after a moderate-sized meal, while waiting at least 30 minutes after a snack is fine.

At that point, food has digested enough to avoid stomach upset. That said, as the intensity of the exercise increases, so does the risk of side effects.

 

Potential side effects

While the side effects that may result from eating close to a workout are highly individual, the most common ones are digestive symptoms and performance issues.

May cause digestive symptoms

Eating too close to working out may cause some digestive discomforts. The most common ones include:

• bloating
• nausea
• cramping
• reflux
• vomiting
• diarrhea
• sluggishness

May affect your performance

While fueling up for an intense training session is important, 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 in 10 male basketball players found that several of them 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.

 

How long should you wait?

The amount of time required to avoid digestive side effects varies by individual and the sport.

While data on the specific amount of time you should wait is limited, here are some general recommendations:

Some endurance sports, such as running, cycling, and cross-country skiing, lasting over an hour may require eating while exercising to maintain energy stores.