## TL;DR
Sports nutrition optimizes timing, quantity, and composition of nutrient intake to maximize training adaptations, competition performance, and recovery.

## Core Explanation
Macronutrient targets vary by sport: endurance athletes need 8-12 g/kg/day carbs; strength athletes need 1.6-2.2 g/kg/day protein. Fat provides essential fatty acids. Glycogen is the limiting fuel for high-intensity exercise — depletion (hitting the wall) occurs at ~2,000 kcal stored glycogen.

## Detailed Analysis
Hydration: as little as 2% body mass loss impairs cognitive and physical performance. Electrolyte replacement (sodium 500-700 mg/L) needed for exercise >2 hours. Caffeine (3-6 mg/kg) is the most researched legal ergogenic aid, improving endurance by 3-5%.

## Further Reading
- IOC Consensus Statement: Sports Nutrition
- Gatorade Sports Science Institute
- ISSN Conferences and Position Papers