Dietary Needs of Adolescent Runners: Calorie and Protein Requirements During Growth

Introduction

A junior high school girl who runs 25 kilometers per week can require up to 600–800 more calories per day than a classmate of the same age who does not exercise. If parents and children are unaware of this difference and maintain the same food intake, it can lead over time to Relative Energy Deficiency in Sport (RED-S)—a serious condition affecting bone density, the immune system, menstrual function, mental health, and even height development. This is a particular concern for young female runners in Taiwan.

This article examines the physiological demands of the growth period, breaks down the calorie, protein, carbohydrate, fat, and micronutrient needs of teenage runners, and offers practical advice suited to Taiwanese dietary habits.

Calorie Needs of Teenage Runners

Basal Metabolic Rate Plus Exercise Expenditure

A teenager’s calorie needs consist of three components:

1. Basal Metabolic Rate (BMR): energy for basic life-sustaining functions
2. Calories for growth: additional energy required for bone and muscle development
3. Exercise expenditure: extra calorie needs from training

Using the example of a 13-year-old female runner who is 160 cm tall, weighs 50 kg, and runs 20–25 km per week:

Many young female runners consume only 1,500–1,800 kcal per day in order to “stay slim,” remaining in a chronic energy deficit without realizing that this is harming their bone development and hormonal system.

Macronutrient Needs and Sources

Carbohydrates: The Primary Fuel for Running

Carbohydrates are the main energy source for endurance sports and an essential fuel for brain function. Teenage runners should not drastically reduce carbohydrate intake for weight management.

Recommended intake: 5–7 g per kg of body weight per day (on training days)

Common high-quality carbohydrate foods in Taiwan:

• White rice, brown rice, oats, multigrain rice
• Sweet potatoes, pumpkin
• Seasonal Taiwanese fruits such as bananas, mangoes, and papayas
• Whole wheat toast, steamed buns

Protein: Dual Demands of Growth and Muscle Repair

Teenage runners have higher protein needs than adult runners because protein must support both muscle repair and physical development.

Recommended intake: 1.4–1.8 g per kg of body weight per day (adult runners typically need 1.2–1.6 g)

For a body weight of 50 kg, this means approximately 70–90 g of protein per day.

Common high-quality protein foods in Taiwan and their content:

• Chicken breast (100 g): ~31 g protein
• Tofu (100 g): ~8 g protein
• Egg (1): ~6–7 g protein
• Salmon (100 g): ~25 g protein
• Greek yogurt (100 g): ~10 g protein

Fat: An Indispensable Raw Material for Hormones

Adequate healthy fats are crucial for hormone synthesis, absorption of fat-soluble vitamins, and nervous system development in teenagers. Daily fat intake should account for 25–35% of total calories, with sources primarily being unsaturated fats: avocado, nuts, olive oil, and fish oil.

Key Micronutrients

Teenage runners should pay particular attention to the following micronutrients:

• Iron: Long-distance running accelerates red blood cell breakdown, and when combined with the additional demands of growth and menstruation in females, iron-deficiency anemia is quite common among young female runners in Taiwan. Eat more red meat, dark green vegetables, and legumes, and consume them with vitamin C to improve absorption
• Calcium: The critical period for building bone density is before age 20, with a daily requirement of at least 1,000–1,300 mg. Milk, yogurt, dried baby fish, and tofu are readily available calcium sources in Taiwan
• Vitamin D: Promotes calcium absorption; levels among Taiwanese teenagers are generally low, so regular testing and appropriate supplementation are recommended

Meal Timing Around Training

• 1–2 hours before training: a light meal focused on carbohydrates (banana, toast, sweet potato)
• Within 30 minutes after training: a carbohydrate + protein combination (milk + banana, yogurt + fruit) supports muscle repair and glycogen replenishment
• Before bed: a moderate amount of protein (such as Greek yogurt) supports overnight growth and repair

Practical Advice

1. Parents should not talk about “weight loss” in front of teenage runners—the harm of energy deficiency to growth and development is far more serious than any number on the scale
2. Watch for red flags: irregular or absent periods (in females), persistent fatigue, and fractures that are slow to heal are all early signs of RED-S
3. Encourage children to eat before and after running—do not let the misconception of “not eating before exercise” deprive them of needed fuel
4. A balanced Taiwanese diet is usually sufficient: a well-balanced Taiwanese bento with rice, vegetables, and protein is actually an excellent foundation for an athlete’s diet
5. If in doubt, consult a sports dietitian rather than adopting trendy diets found online on your own

Conclusion

The body of a teenage runner is undertaking two high-energy projects simultaneously: growing up, and running. Each requires adequate nutritional support, and doing both at once demands careful planning. Parents’ attention to their children’s diet should not stop at “as long as they eat something.” It is essential to understand that a sufficient, balanced diet is the most powerful foundation for helping children run well and grow tall.

Related Reading

• Nutrition for Teenage Athletes: Calculating Calories for Growth and Training Demands
• Special Nutritional Needs of Teenage Swimmers: Dietary Strategies During the Growth Period
• Nutritional Needs of Teenage Swimmers: Calories and Micronutrients During Growth
• Daily Protein Requirements for Runners: Food Sources for 1.4–1.7 g per kg of Body Weight