Module 20
Sports Nutrition Brain-Fuel Guide
What active kids need before, during, and after exercise to protect both performance and cognitive function
How to Use This
How to Use This: Start with the daily calorie table to confirm your young athlete is eating enough total calories. Then use the pre/during/post exercise sections to structure fueling around training. Review the RED-S red flags checklist to rule out under-fueling.
Key Terms
Key terms: Glycogen is stored carbohydrate energy in muscles and liver — the body's primary fuel during exercise. RED-S (Relative Energy Deficiency in Sport) is a syndrome caused by chronically eating too few calories relative to activity, harming bones, hormones, brain, and immune function. Myelinating means building the insulation layer on brain nerve fibers, critical during adolescence.
Active adolescents face a double demand: fueling physical performance AND rapid brain development. The adolescent brain is still under heavy construction — pruning synapses, myelinating connections, developing executive function. Under-fueling doesn't just hurt athletic performance. It impairs learning, mood regulation, and brain maturation. Most young athletes are chronically under-eating, especially girls.
Daily Calorie & Macronutrient Needs
| Moderately Active | Very Active (daily training) | Competitive/Elite | |
|---|---|---|---|
| Calories (girls 13-18) | 2,000-2,200 | 2,400-2,800 | 2,800-3,200+ |
| Calories (boys 13-18) | 2,200-2,600 | 2,800-3,200 | 3,200-4,000+ |
| Protein | 1.0-1.2 g/kg/day | 1.2-1.6 g/kg/day | 1.4-2.0 g/kg/day |
| Carbs | 3-5 g/kg/day | 5-7 g/kg/day | 6-10 g/kg/day |
| Fat | 25-35% of calories | 25-35% of calories | 25-35% of calories (don't cut fat — brain needs it) |
Pre-Exercise Fueling (1-3 Hours Before)
The goal: top off glycogen stores, provide steady energy, avoid GI distress. Carbohydrate-dominant with moderate protein. Low fat and low fiber close to game time.
| Timing | What to Eat | Portion Guide | Examples |
|---|---|---|---|
| 3 hours before | Full meal: carbs + protein + small amount of fat | Plate-sized meal | Pasta with chicken and marinara; rice bowl with salmon and veggies; turkey sandwich + fruit |
| 1-2 hours before | Lighter meal: mostly carbs + some protein | Snack to small meal | Oatmeal with banana; PB&J on white bread; yogurt parfait with granola |
| 30-60 min before | Simple carbs only — easy to digest | Small snack | Banana; applesauce pouch; few crackers; dried fruit; sports drink |
During Exercise
| Duration | Hydration | Fuel | Notes |
|---|---|---|---|
| Under 60 min | Water: 4-8 oz every 15-20 min | None needed | Water is sufficient for short, moderate activity |
| 60-90 min | Water or diluted sports drink | Optional: 15-30g carbs (half a banana, few orange slices) | Important in heat or high-intensity sport |
| 90+ min | Sports drink: 4-8 oz every 15-20 min | 30-60g carbs per hour (sports drink covers this, or add a bar, gels, fruit) | Critical for endurance sports, tournaments with multiple games |
Important
Avoid energy drinks (Monster, Red Bull, Bang). These contain 150-300 mg caffeine — the AAP recommends adolescents consume no more than 100 mg/day. Energy drinks also contain stimulants and sugars that cause crashes. Stick to water and real sports drinks for hydration.
Post-Exercise Recovery (Within 30-60 Minutes)
The recovery window matters. Glycogen replenishment is 50% more efficient within the first 30 minutes after exercise. Protein synthesis peaks in the 2 hours post-exercise. Don't let them skip post-workout nutrition.
| Recovery Goal | What to Eat | Examples |
|---|---|---|
| Replenish glycogen | 0.5-0.8 g carbs per kg body weight | Chocolate milk (top research-backed recovery drink); banana + granola bar; rice + chicken |
| Repair muscle | 15-25g protein | Greek yogurt (18g per cup); 3 oz chicken (24g); chocolate milk (8g per cup); 2 eggs (12g) |
| Reduce inflammation | Omega-3 fats + antioxidants | Salmon; berries; tart cherry juice (research-backed for muscle recovery); nuts |
| Rehydrate | 16-24 oz fluid per pound lost during exercise | Water + electrolytes. Weigh before and after practice to estimate sweat loss. |
Brain-Specific Nutrients for Active Adolescents
| Nutrient | Why Athletes Need More | Daily Target | Top Sources |
|---|---|---|---|
| Iron | Lost in sweat and foot-strike hemolysis (running). Female athletes are at highest risk. Low iron = brain fog, fatigue, poor concentration. | Girls: 15 mg/day; Boys: 11 mg/day | Red meat, liver, lentils, fortified cereal, dark leafy greens |
| Calcium & Vitamin D | Peak bone building happens NOW. Low intake = stress fractures + long-term osteoporosis risk. | 1,300 mg calcium; 600+ IU vitamin D | Dairy, fortified alternatives, sardines, broccoli. Vitamin D: sunlight + supplement. |
| Magnesium | Lost in sweat. Involved in 300+ enzymatic reactions. Low = cramps, poor sleep, impaired recovery. | 360-410 mg/day | Pumpkin seeds, almonds, dark chocolate, spinach, avocado, bananas |
| DHA/Omega-3 | Anti-inflammatory, neuroprotective. Reduces exercise-induced brain inflammation and supports concussion recovery. | 250-500 mg DHA/day | Fatty fish 2-3x/week, fish oil supplement, algae DHA |
| Zinc | Lost in sweat. Critical for growth hormone production, immune function, and wound healing. | 8-11 mg/day | Red meat, oysters, pumpkin seeds, chickpeas, yogurt |
| B Vitamins | Increased demand for energy metabolism. B12 and folate needed for red blood cell production. | Varied by B vitamin | Meat, eggs, dairy, legumes, whole grains, leafy greens |
Red Flags: Signs of Under-Fueling (RED-S)
Relative Energy Deficiency in Sport — affects brain, bones, hormones, and immune function
The Chocolate Milk Secret
Low-fat chocolate milk is one of the most research-validated recovery beverages available. It delivers the ideal 3:1 carb-to-protein ratio, electrolytes, fluid, and calcium. Multiple studies show it performs as well as or better than commercial recovery drinks. Cost: about $0.50 per serving. Keep it stocked.
Important
If your teen athlete shows 3 or more RED-S red flags, seek medical evaluation promptly. Under-fueling during adolescence can cause irreversible bone density loss, hormonal disruption, and impaired brain development. Do not wait for performance decline — early intervention matters.
Next Steps
Next Steps: Calculate your teen's approximate daily calorie needs from the table, then compare it to what they actually eat. If there's a gap, use the pre/during/post fueling templates to add structured eating around training. Review the Nutrient Gap Identifier for brain-specific nutrients.
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