When you should eat to fuel your workout

You finished eating dinner 15 minutes before your run, and now you’re cramping and gasping for air. Maybe early morning is your only time to work out, but you woke up hangry and don’t know if you can make it through a weightlifting session.

Determining how to time your eating to maximize exercise benefits can feel tricky. Here, fitness experts share tips that can help you cut stress and discomfort out of the equation and give your body the fuel it needs.

Whether and how soon you should eat before working out depends on the intensity of the exercise you’ll be doing.

A man wearing a fitness tracker prepares a protein shake.

“If you’re looking at a very high-intensity workout, you’re going to need to have fuel in order to be able to utilize that glucose, the sugar, for energy,” said physical therapist Nicholas Rolnick. Glucose, which we mainly get from carbohydrate-rich foods, is our body’s primary source of fuel.

“If you’re not giving your body the fuel that it needs in order to maximally exert yourself in those short periods of time, along with the ability of your body to resynthesize some of that energy during the workout itself, the intensity of your workout is not going to be as high as it would have been had you had some carbs to help with sustaining that workout,” he said.

Important note: Before beginning any new exercise program, consult your doctor. Stop immediately if you feel pain.

Planning your pre-workout meals and snacks

Negative effects of exercising on an empty stomach also include “feeling light-headed, getting a headache, feeling faint and feeling weak,” said Stephanie Mansour, a personal trainer and weight loss coach, via email. Conversely, if you eat too soon or too much before your workout, digestion will steal some of the energy your muscles need to do their job.

You should eat between one and four hours before you exercise, according to consensus among experts, including the American Heart Association and the Academy of Nutrition and Dietetics. Consuming enough food and fluids – 16 to 20 ounces of water – before you work out is also important for balancing fluid losses and improving the quality and length of recovery time, according to the American College of Sports Medicine.

Related article The foods you should eat to jump-start your morning, and 2 recipes to try out

The harder your muscles work, the more carbs they will need to keep going, wrote registered dietitian Christopher Mohr for Eat Right, a publication of the Academy of Nutrition and Dietetics. To fuel your rigorous workout, Mohr suggested eating oatmeal with low-fat milk and fruit, or a peanut butter and banana sandwich.

“Notice that each of these suggestions include some protein as well as carbohydrates,” Mohr wrote. “Carbs are the fuel. Protein is what rebuilds and repairs, but also ‘primes the pump’ to make the right amino acids available for your muscles.” Amino acids help the body repair tissues, grow and further break down food.

Your pre-workout plate should contain mostly carbohydrates and a moderate amount of lean protein, according to the Cleveland Clinic. Limit dietary fats and fiber since those take longer to digest.

On unique schedules and diets

If early mornings are the time you exercise, you might think eating one to four hours prior isn’t feasible. If you aren’t someone who prefers exercising before eating, what you can do in this case is have a small, easily digestible snack to get yourself going a bit beforehand, Rolnick said.

Related article 18 comfortable pairs of sneakers to walk all day in (Courtesy CNN Underscored)

That light morning snack could be apple slices with nut butter, a banana, or Greek yogurt and berries. You also could use this advice if you’re doing a short, light-intensity workout at any point of the day, the Cleveland Clinic advised.

“As a weight loss coach for women, I recommend that my clients have a hard-boiled egg or a handful of almonds before a workout, even if it is within only 30 minutes of exercising, so that they have enough energy to complete their workout,” Mansour said. You could also drink a protein shake, she added.

“Eating earlier in the day also speeds up the metabolism, which helps to speed up weight loss,” Mansour said.

Whether and how soon you should eat before working out can also depend on your desired outcomes from the exercise: Some people who follow low-carb, ketogenic or intermittent fasting lifestyles try to work out while their glucose stores are low, so that they can burn fat instead of stored calories or food they recently ate.

“If this is part of your protocol, then try it out and see how you feel,” Mansour said. “Keep in mind that while you’re fasting, lower-intensity workouts will probably help you feel steadier and less fatigued compared to a high-intensity workout.”

Overall, you should listen to your body. “At the end of the day, you are your own best trainer and instructor. If it doesn’t feel good to eat before a workout, then don’t,” Mansour said. “But if you’re doing the same things and not happy with your results, then change it up. Eat before the workout, eat after the workout, change up the workouts, and ultimately listen to your body and modify your strategies to reach your goals.”