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Pre-Workout Fueling

Granola with yogurt and berries


Young student-athletes are often faced with a tough challenge when rushing to practice after school. How do you fuel for a practice or workout with limited time and when lunch is often hours before the final bell rings?

TrueSport Expert Kristen Ziesmer, a registered dietitian and board-certified specialist in sports dietetics, shares what parents and coaches need to know about pre-workout fueling for middle and high school athletes.

Understand youth energy needs

“Kids’ energy needs are a double-edged sword,” says Ziesmer. “Because of their metabolism and everything going on in their bodies as they develop, their energy needs are going to be higher per kilogram of body weight as opposed to an adult. But because they weigh less, their caloric needs will still often be less than an adult.”

Any time you’re trying to calculate caloric needs, especially when it comes to pre-workout carbohydrate needs, the amount per kilogram of body weight that they need is higher than an adult would need. You can use this handy table to get a sense of your child’s needs based on age and sex, but it will vary slightly based on weight. Ziesmer also notes that you might be shocked by how much your athlete needs. Between the energy cost of the workout and the daily requirements for a growing body, they really are burning through those calories.

Hydration matters

Hydration needs are also a bit higher, due to the fact that children have more surface area on their body proportionate to their weight, so they dehydrate faster than adults do. Ziesmer notes that kids, and even teens, are not as aware of hunger or thirst cues, especially during play (or practice). Make sure your athlete is always equipped with a water bottle at school and encourage them to sip steadily throughout the day rather than chugging a liter of water just before practice.

Tell your athlete to eat early

It can be tricky with school schedules and rules around eating in class, but your athlete does need to pre-fuel for practice, especially for practices like cross-country running where energy expenditure is high.

If lunch is early in the day – more than three hours ahead of practice, then Ziesmer recommends, “An hour before practice is good for a small snack because that gives your athlete time to digest their food. When eating an hour before, you need roughly one gram of carbohydrates per kilogram of body weight. So, if an athlete is 150 pounds, or 68 kilograms, then they need approximately 68 grams of carbs, 5-10g protein. A sample snack would be 8 ounces of 100 percent fruit juice, 1 serving of whole grain crackers, and 1 tablespoon of peanut butter or 1 light string cheese.”

Skip protein bars

“I am not opposed to a Clif Bar, for example, because it’s whole foods that are compressed into bar form,” Ziesmer says. “But I definitely advise against bars that are packed with protein and chemicals, like a Quest bar.” In addition to the highly processed nature of bars, a lot of these bars are marketed for sports but are actually protein-based, so they aren’t ideal for eating ahead of practice.

“The problem with protein bars is if an athlete is eating too much protein before practice, then the stomach is really too busy trying to digest that food,” she explains. “A lot of the athlete’s blood is now in the intestines trying to digest the food rather than being delivered to working muscles, which is going to sink the performance.”

Aim for whole foods

Ziesmer urges parents to provide whole food options whenever possible in order to ensure that your young athlete doesn’t begin to depend on processed snacks. “It is really hard to get a good balance of macronutrients in a bar, and real food is just a better choice due to digestibility and nutrient content” she adds. Some options that should be easy for your athlete to eat between classes include:

  • Half a bagel with nut butter

  • Pita with hummus

  • Yogurt with fruit and granola

  • Half of a peanut butter and jelly sandwich

  • Half of a turkey sandwich

  • Handful of pretzels with some watered-down fruit juice



Encourage your athlete to eat the right foods at the right time before a workout for improved performance and decreased likelihood of fatigue and injury.

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Nutrition Parent TrueSport