You’ve probably heard the tale that warns against jumping into the pool
right after eating. Though it’s probably alright to swim after a meal, you
may want to wait at least 30 minutes to avoid muscle cramps.
But just how long should you wait to go for a run or lift weights after
eating? Here’s what we as dietitians recommend to properly fuel for your
You shouldn’t exercise right after eating a big meal . Eating before a
workout is critical to perform your best. But what that looks like will
depend on the type of workout and size of your meal.
There are a few common rules of thumb you should follow:
- Basically, the bigger the meal, the more time you should wait to
work out. Eating a heavy meal immediately before a workout can
cause GI discomfort — like bloating and cramping — and will not
result in optimal performance due to competing demands between
your muscles and digestive system.
- For vigorous exercises like high-intensity interval training or
weight-lifting consume a low-fibre snack about 30 to 45 minutes
before engaging. Here are some other easily digestible
carbohydrates that will break down quickly to provide fuel: bananas,
nut butter on toast, yogurt and granola, or energy bars.
- For high-endurance activities like running or swimming, you’ll need
to store up more energy longer before your workout. For this type of
exercise, rather consume a mix of carbohydrates and protein two to
three hours before exercise, such as a whole wheat sandwich with
peanut butter or yogurt with fruit.
The next question would be how long to wait before an extensive workout
like a marathon? Distance runners will also want to eat high-carbohydrate
meals well in advance of a marathon. Sometimes we will recommend
carbo-loading two to three days before a race with pasta, rice, and
With physical activities sustained over long periods of time, the body uses
stored carbohydrates and fats for energy consumption, so you’ll need to
load up ahead of time to stay fresh for the final miles. When there are no
carbohydrates readily available in the bloodstream, the body relies on
energy stores called glycogen, which can get depleted during an intense
or long exercise session and hinder your performance.
Just make sure you don’t show up to the race hungry — a granola bar or
banana 30 minutes to one hour before you head to the starting line should
do the trick. And you should probably stay away from any high-fat foods
immediately before exercise.
The bottom line: Do what works for you but don’t be irresponsible.
Ultimately, it’s up to you to pay attention to how different foods affect your
workout performance, and you should take note of how you feel with
varying lengths of time in between eating and exercising.