Sep 9, 2016
Fueling Makeover
Susan Kundrat

Increasing daily calories can be a tricky sell with high school athletes. On the one hand, some will welcome it — seeing it as the solution to their struggles with building lean mass. Others will view it negatively, believing more calories will lead to unwanted weight gain.

But whether athletes are for or against upping their calorie count, there’s no denying the impact running on empty can have on performance. Few high school athletes know how many calories are required to fuel their activity, and when they don’t get enough, it leaves them sluggish for training. In the following case study, we examine a high school runner who needed an upgraded fueling plan.


Robin was a dedicated 15-year-old high school distance runner who came to see me after two weeks of poor performances during training. Her weekly mileage had increased from 30 to 40 miles, and she was feeling drained during practices. Concerned that she was no longer meeting her time goals, Robin’s coaches encouraged her to look more closely at her diet. They assumed she wasn’t eating enough to fuel her activity.

At our first consultation, Robin measured 5 feet 7 inches tall and weighed 130 pounds. Her lean mass was 109 pounds, fat mass was 21 pounds, and body composition was 16 percent body fat. I learned she followed a lacto-ovo vegetarian diet, meaning she ate milk products and eggs, and that she had agility and strength workouts three mornings a week in addition to daily after-school practices.

To get a better sense for what could be causing Robin’s low energy during training, I asked her to compile a sample daily menu. A typical day’s intake for Robin included:

Breakfast: Two slices of whole wheat toast with peanut butter and eight ounces of orange juice (400 calories)

Post-workout (on morning workout days): 10 ounces of lowfat chocolate milk (150 calories)

Lunch: Hummus sandwich on a pita with veggies, an orange, an apple, and baked chips with water (500 calories)

Pre-practice snack: Granola bar (100 calories)

During practice: Water

Post-practice dinner: Pasta with pesto, broccoli, yogurt with strawberries, and water (600 calories)

Snack: A bowl of whole grain cereal with milk (300 calories).


My first thought upon looking at Robin’s rundown was that her calorie intake of about 2,050 per day was way too low. Based on her bodyweight, training plan, history of fatigue, and difficulty getting through workouts, she required between 3,000 and 3,200 calories per day.

Robin’s protein and carbohydrate intakes were low, as well. Although she ate high-quality sources of protein like dairy products, eggs, and soy, she was only consuming about 80 grams daily. At Robin’s training level, her protein needs were at least 0.7 to 0.8 grams per pound of bodyweight per day, or around 90 to 105 grams.

For carbohydrates, Robin was consuming a little more than half of what she needed to fuel performance — about 300 grams per day. An ideal range would be as much as four to five grams of carbohydrate per pound of bodyweight per day, or 520 to 650 grams.

Besides the eating log, I recommended some lab work, which found Robin had low ferritin levels. The combination of low iron stores and low energy intake can spell trouble for distance runners. Because iron stores help the body utilize oxygen, and thus aid in enhancing endurance training and performance, optimizing them is critical.


Once I knew what was causing Robin’s performance issues, I could revamp her fueling plan accordingly. I wanted to increase her energy intake throughout the day, add protein to breakfast and before bed to optimize utilization, and spread carbohydrate fueling more evenly.

However, Robin wasn’t keen on some of these ideas at first. While she knew she needed to consume more calories, she was hesitant to eat more. Like many athletes in sports where a lower bodyweight can be beneficial to performance, Robin wanted to stay lean.

To address these concerns, I highlighted the benefits of fueling her body more fully, which would include increased energy, a boost in training, and enhanced performance. I also focused on making minor tweaks to Robin’s existing meal plan.

For example, she could increase 220 grams of carbohydrate (880 calories) per day simply by switching to 100 percent juice with meals instead of water, eating more fruits, and drinking smoothies. Because she was drinking a lot of water anyway, switching to higher-calorie fluids did not make her feel overly full. Adding more eggs, cheese, yogurt, and milk were also good options for upping her calories and protein.

Here’s what Robin’s new performance plan looked like:

Breakfast: Two scrambled eggs with cheese, two slices of whole wheat toast, and a smoothie with eight ounces of orange juice, one banana, and half a cup of Greek yogurt on non-workout days (600 calories) and two slices of whole grain toast with peanut butter and eight ounces of orange juice on workout days

Post-workout (on morning workout days): Nut and seed bar and 20 ounces of lowfat chocolate milk (400 calories)

Lunch: Hummus sandwich on a pita with veggies, an orange, an apple, baked chips, and 16 ounces of 100 percent cranberry juice (750 calories)

Pre-practice snack: Homemade trail mix and eight ounces of apple juice (300 calories)

During practice: 20-ounce sports drink and water (100 calories)

Post-practice dinner: Pasta with pesto, broccoli, yogurt with strawberries, and 16 ounces of orange juice (700 calories)

Snack: One cup of Greek vanilla yogurt with one-third of a cup of granola and one sliced banana (400 calories).

To increase Robin’s iron intake, she began taking iron supplements (65 milligrams of iron as ferrous sulfate) with 500 milligrams of vitamin C daily to enhance absorption. She also focused on eating more eggs, greens, legumes, and other iron-fortified foods. Altogether, Robin’s new meal plan had her consuming approximately 3,250 calories, 110 grams of protein, and 520 grams of carbohydrate per day.

For Robin, adding more calories to her diet took some getting used to. However, by making small, gradual changes and connecting them to her improved performance, she became more comfortable with the plan over the course of a month. She found she had more energy, got through workouts better, and recovered faster — all of which helped get her race times back on track.

Susan Kundrat, MS, RD, CSSD, LDN, is a Clinical Associate Professor of Kinesiology and the Nutritional Sciences Program Director at the University of Wisconsin-Milwaukee.

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