Fueling Your Distance Runner: What Every Parent Should Know
Fueling comes up in almost every conversation we have with parents, right up there with training itself. And it usually comes with the same worry attached: "I don't want to get this wrong."
Here's the short version. A growing teenage athlete needs more food, not less. That's the biggest mistake we see. A high schooler putting in real mileage is also going through normal adolescent growth at the same time, and asking their body to do both on too little food, whether on purpose or by accident, is one of the fastest ways to watch performance stall, mood and energy tank, and injury risk climb.
None of what follows requires a strict meal plan or cutting out foods. It's really just about eating real meals, consistently, and treating food as part of training instead of an afterthought.
Why Fueling Matters More Than Most Families Realize
Underfueling in young endurance athletes is common, and it's easy to miss because it rarely looks like a textbook eating disorder. More often it looks like a kid who's "just tired," who's "always catching something," or who can't seem to shake one nagging injury before the next one shows up.
A study of collegiate cross country runners found low energy availability, meaning the athlete isn't taking in enough fuel to cover both training and normal growth, in a surprising number of them: 42% of the men and 29% of the women (McCormack et al., European Journal of Applied Physiology, 2019).
That condition sits at the center of what sports medicine calls Relative Energy Deficiency in Sport, or RED-S. Left unaddressed, it's been linked to poor bone health, more injuries, and stalled performance in both boys and girls (Gould, Ridout & Newton, International Journal of Sports Medicine, 2023).
Don't Skip Breakfast
Plenty of teenagers head out for a morning run or straight to practice on an empty stomach, usually out of habit or because they're rushing. Skipping breakfast on a training day isn't toughness. It's leaving performance on the table.
Something small 30 to 60 minutes beforehand, like toast with peanut butter or a banana, makes a real difference in how a workout feels, especially once summer heat sets in. In one study of nearly 1,850 Chinese teenagers, boys who regularly skipped breakfast ran noticeably slower 1000m times than boys who ate breakfast consistently (Hu et al., Clinics, 2020).
The Recovery Window
Right after a hard practice or long run, the body is primed to use protein and carbohydrates to repair and adapt. That's why something like chocolate milk, a sandwich, or yogurt with fruit shortly after practice matters, rather than waiting it out until dinner a few hours later.
Sports nutrition guidelines generally point to roughly 1.0 to 1.2 grams of carbohydrate per kilogram of body weight per hour during the first few hours after hard training, paired with some protein, to help speed up glycogen replenishment and muscle repair (Kerksick et al., International Society of Sports Nutrition Position Stand, 2017).
Hydration Is a Daily Habit, Not a Race Day Fix
Losing just 2% of body weight through sweat is enough to measurably hurt performance, and that's an easy number to hit on a hot practice day, often before a runner even feels thirsty (Sawka et al., American College of Sports Medicine Position Stand, Medicine & Science in Sports & Exercise, 2007).
We'd much rather see a runner sipping water all day than trying to cram it in during the 20 minutes before practice. Teenagers especially tend to show up already behind on hydration simply because they got busy and forgot to drink.
Iron: The Hidden Risk, Especially for Girls
Iron deficiency is one of the most common issues in teenage distance runners, and one of the most overlooked. A classic study that tracked high school cross country runners across an 11-week season found deficiency rates climbing steadily as the season went on: from 40% to 45% in girls, and from 3% to 17% in boys (Rowland, Black & Kelleher, Journal of Adolescent Health Care, 1987).
Fatigue and slow recovery tend to get blamed on training load. Sometimes it really is iron. If a runner's performance or energy drops off without an obvious training cause, it's worth asking a doctor for bloodwork instead of assuming it'll work itself out.
Daily Targets for a Training Teenager
These are general ranges pulled from published sports nutrition reviews, not hard rules. Every runner's needs shift depending on training load, growth, and body size (Everett, Nutrients, 2025):
Carbohydrate: roughly 6 to 10 grams per kilogram of body weight, daily
Protein: roughly 1.2 to 2.0 grams per kilogram of body weight, daily
In practice, that means carbohydrate-rich foods like whole grains, fruit, potatoes, and rice at every meal, plus a protein source spread across the day rather than saved for one big meal. Fat shouldn't be restricted either. It plays a real role in hormone health, which matters a lot during adolescence.
Signs of Underfueling to Watch For
Keep an eye out for these signs, not just a dip in race times. They can show up even in a runner who seems to be eating normally:
Constant fatigue that doesn't improve with rest
Getting sick more often than usual
Noticeable mood changes
A string of nagging injuries, especially bone stress injuries
Missed or irregular menstrual cycles in female athletes
If this pattern sounds familiar, it's worth a conversation with a doctor or sports dietitian rather than assuming it'll resolve on its own.
What the Experts Say
We're coaches, not dietitians, so we lean on people who specialize in this. Heather Fink, a Registered Dietitian and Board-Certified Specialist in Sports Dietetics based in Indianapolis, has spent more than 20 years working with collegiate and individual endurance athletes. Her approach is built around sustainable, individualized fueling rather than restrictive plans.
Sports dietitian Nancy Clark, who has spent 40 years counseling athletes from high schoolers to Olympians, puts it plainly: "Carbohydrates are the preferred source of muscle fuel for hard exercise. Serious athletes who minimize carb intake risk having poorly fueled muscles." Her larger point is that being thinner doesn't make you faster if it comes at the cost of skimpy meals and underfueled muscles.
What a Fueled Day Actually Looks Like
No meal plans, no cutting out foods. Just consistent, real food built around training:
Before morning practice: toast with peanut butter, or a banana
Breakfast: eggs, oatmeal, or cereal with milk and fruit
Lunch: sandwich or wrap, fruit, and a starchy side
Within 60 minutes after practice: chocolate milk, a sandwich, or yogurt with fruit
Dinner: a balanced plate with protein, carbohydrate, and vegetables
Throughout the day: water, sipped consistently rather than chugged right before practice
The teenage runners who fuel well aren't on complicated diets. They're just eating real meals consistently instead of skipping them under time pressure.
Want the full guide with all the research citations? Download the complete RM Distance Collective Fueling Guide below.
Have questions about your runner's fueling, training, or recovery? DM us on Instagram @RM_DistanceCollective or visit indianadistancecollective.com.
