How long to wait after eating to exercise?

According to the Academy of Nutrition, you should wait at least one hour after eating to exercise [1]. 

For optimal performance, you should eat carbohydrate-rich foods paired with some protein 1-4 hours before exercise, depending on how your body tolerates food [1]. Research shows strategic fuel consumption in the hours leading up to a tough training workout or endurance event can boost performance by maximizing muscle and liver glycogen stores and maintaining adequate blood glucose levels [2]. 

While it's good to have energy on board, eating too much, too close to exercise may put a strain on performance since both exercise and digestion require significant energy and blood flow. It may also lead to some unpleasant GI symptoms like cramping, indigestion, or diarrhea [1].

If you’re not able to eat within the 1-4 hour window, or prefer to exercise first thing in the morning, studies show having a small carbohydrate-rich snack or beverage 30-60 minutes before can increase exercise capacity, if tolerated [2]. 

The International Society for Sports Nutrition recommends pre-exercise meals be at least 55-65% calories from carbohydrate and also contain some lean protein and healthy fat [1]. Some easy, pre-workout snack ideas include a serving of pretzels, a small piece of fruit, slice of whole grain toast with jam, or 8-ounces of a sport drink. As always, experiment with pre-exercise eating and do what works best for you.