How long before a workout should you eat?
Luckily, there is a health-expert-approved guideline you can follow closely. "You should usually wait for one to two hours after a meal before beginning a strenuous workout," says Victor Romano, MD, an Illinois-based orthopedics and sports medicine specialist. "The body needs time to digest the food, which requires energy and increased blood flow to the stomach."
It typically takes food anywhere from two to four hours to fully transition from your stomach to your small intestine after you eat, and while you don't need to wait until your breakfast (or snack, lunch, and so on) are fully digested, it will feel best if you give your body some time to process your meal before you hop into a HIIT class.
"You should usually wait for one to two hours after a meal before beginning a strenuous workout." —Victor Romano, MD
That being said, the science of not gagging halfway through your workout is not a perfect one, and this is largely because everyone metabolizes food differently, according to Amanda Lemein, MS, RD, LDN, a Chicago-based dietitian. She adds that there are two important factors to consider when it comes to timing your workout fuel properly: First, your own habits and body. Second, the size and contents of the meal.
Meal size and composition matter
Both the amount of food that you're eating and what you choose to nosh on pre-workout will largely determine how long you should wait before exercising. As Lemein emphasizes, everyone's needs are different in this area—but generally-speaking, the larger the meal you consume, the longer it will take to digest. This ups the amount of time you should wait before working out.
In addition, foods that are higher in fiber, protein, and fat will be digested slower than meals containing a larger proportion of simple carbohydrates and/or lean protein. To shorten the amount of time you'll need to wait before you feel comfortable exercising after a meal, go for carbs and lean proteins. These will both provide sustained energy without slowing down your digestive process.
Potential side effects of exercising too soon after you eat
If you start exerting yourself too soon after eating, Lemein warns that your body will start sending most of its energy toward your muscles, keeping your food from digesting. She adds that this is especially true for larger meals that are more likely to put you in a "snooze" than "sprint" mindset. "It can really affect your performance when you’re [feeling] a little sluggish, and therefore you’re really not getting the most out of it anyway."
Specific side effects will vary from person to person greatly, but jumping the gun on that post-lunch spin class could result in a few of these uncomfortable symptoms:
- Acid reflux
What to eat after exercise: pre-workout snack ideas
As mentioned, try to eat something with both carbohydrates and a bit of lean protein at least one to two hours before you exercise. A few delicious ideas that won't cause stomach discomfort are banana with peanut butter, fruit and soy milk smoothies, oatmeal or yogurt with fresh berries, dried fruit with nuts, or almond butter and jelly on whole wheat bread.
If you are short on time and cannot wait the full one to two hours, Lemein recommends nixing the protein and just going for simple forms of carbohydrates, like applesauce, fruit leather, raisins or dates, or crackers.
Everyone metabolizes and digests food differently, so if you're really looking to optimize your snacking regimen for optimum performance, try taking note of which foods help you reach that coveted post-gym high, and which ones make you feel queasy mid-pike press.
You can also try a digestion-boosting workout, like this one from Tracy Anderson, to get your gut back on track if you're feeling bleh.
Originally posted July 30, 2018, updated March 5, 2021 with additional reporting by Betty Gold.
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