Sports nutrition is the application of nutritional science to support training, performance, recovery, and overall health in physically active individuals. Proper fueling optimizes training adaptations, delays fatigue during competition, and accelerates recovery between sessions.

Sports nutrition optimizes performance through strategic nutrient timing, hydration, and energy availability. Source: Unsplash.

Energy Balance and Body Composition

Athletes have higher energy needs than sedentary individuals. Daily energy expenditure includes resting metabolic rate (60-75%), thermic effect of food (10%), and physical activity (15-30% for most, 50%+ for elite endurance athletes). For endurance athletes training 1-2 hours daily: 2,500-4,000+ kcal/day (men) and 2,000-3,500+ kcal/day (women). For strength athletes: 2,800-4,500+ kcal/day depending on size and training volume. For weight loss, a modest deficit of 300-500 kcal/day preserves performance better than aggressive restriction.

Carbohydrates: The Primary Fuel

Carbohydrate is the primary fuel for moderate to high-intensity exercise. Muscle glycogen (300-500 g) and liver glycogen (80-110 g) are the main stores. Daily carbohydrate needs depend on training volume. General health: 3-5 g/kg/day. Moderate exercise (1 hour/day): 5-7 g/kg/day. Endurance training (1-3 hours/day): 6-10 g/kg/day. Extreme training (4+ hours/day): 8-12 g/kg/day.

Pre-exercise: a meal of 1-4 g/kg of carbohydrate 3-4 hours before exercise, plus a small snack (30-60 g) 30-60 minutes before if tolerated. During exercise lasting over 60-90 minutes: 30-60 g of carbohydrate per hour (up to 90 g/hour for elite endurance athletes using multiple transportable carbs — glucose + fructose). Post-exercise: 1-1.2 g/kg within 30-60 minutes for rapid glycogen resynthesis, especially if training again within 8 hours.

Proteins: Muscle Repair and Adaptation

Protein is essential for muscle protein synthesis, repair, and adaptation to training. The recommended daily intake for athletes is 1.2-2.0 g/kg/day (compared to 0.8 g/kg/day for sedentary individuals). Endurance athletes need 1.2-1.6 g/kg/day. Strength athletes need 1.6-2.2 g/kg/day. Protein should be distributed evenly across meals (3-4 meals of 0.25-0.4 g/kg per meal) to maximize muscle protein synthesis.

Post-exercise protein ingestion of 20-40 g (0.25-0.4 g/kg) of high-quality protein stimulates muscle protein synthesis for 2-4 hours. Leucine (2-3 g per meal) is the primary amino acid trigger for muscle protein synthesis. Whey protein is a high-quality, rapidly digestible source rich in leucine. Casein is slower-digesting, providing prolonged amino acid release.

ⓘ Information

The concept of a narrow “anabolic window” (30-60 minutes post-exercise) has been refined. While immediate post-exercise protein intake is optimal, the window extends to at least 2-4 hours post-exercise (and potentially up to 24 hours, especially for those who ate a pre-workout meal). The total daily protein intake and distribution across meals are more important than exact timing. However, for athletes training fasted or with multiple sessions in the same day, immediate post-exercise protein is more critical. A practical approach: consume 20-40 g of protein within 2 hours after each training session.

Fats

Fats are the primary fuel during low-intensity exercise and provide essential fatty acids and fat-soluble vitamins. Athletes should consume 20-35% of total energy from fat (0.8-1.5 g/kg/day). Emphasize unsaturated fats: olive oil, avocados, nuts, seeds, fatty fish. Saturated fat should be under 10% of total energy. There is no demonstrated performance benefit to very low-fat diets for athletes.

Hydration

Dehydration of 2% body mass impairs both aerobic and cognitive performance. Pre-exercise: drink 5-10 mL/kg of fluid in the 2-4 hours before exercise. During exercise: 0.4-0.8 L/hour depending on sweat rate, environment, and exercise intensity. Post-exercise: 1.25-1.5 L of fluid per kg of body weight lost during exercise (sodium in the rehydration solution improves fluid retention). Electrolyte replacement is needed during exercise lasting over 1 hour, in heat, or for heavy sweaters. Sports drinks providing 6-8% carbohydrate with electrolytes balance fueling and hydration.

Ergogenic Aids

Caffeine (3-6 mg/kg, 60 minutes before exercise) improves endurance performance, reduces RPE, and may enhance strength and power. Creatine monohydrate (3-5 g/day, or 20 g/day for 5-7 days loading) improves strength, power, and lean mass gains. Beta-alanine (3-6 g/day for 4+ weeks) improves high-intensity exercise lasting 60-240 seconds by increasing muscle buffering capacity. Nitrate (beetroot juice, 300-500 mg nitrate, 2-3 hours before) improves exercise efficiency and endurance. Sodium bicarbonate (0.3 g/kg, 60-90 minutes before) improves short-term high-intensity performance but causes GI distress in some. Protein supplements (whey, casein) and carbohydrate supplements (maltodextrin, sports drinks) are effective when dietary intake is insufficient.

Nutrient Timing for Competition

Pre-competition meal (3-4 hours before): high carbohydrate, moderate protein, low fat, low fiber — familiar foods. Pre-event snack (30-60 minutes before): 30-60 g carbohydrate (banana, sports bar, bagel). During event (over 60 minutes): 30-60 g carbohydrate per hour. Post-event (within 2 hours): carbohydrate (1-1.2 g/kg) plus protein (20-40 g). Rehydration to baseline body weight.

Group exercise classes combine social support with structured workouts for improved adherence and results. Source: Unsplash.

Summary

Athletes need higher energy, carbohydrate, and protein intakes than sedentary individuals. Carbohydrate is the primary fuel for moderate to high-intensity exercise. Protein needs are 1.2-2.2 g/kg/day distributed across meals. Hydration before, during, and after exercise is critical for performance. Evidence-based ergogenic aids (caffeine, creatine, beta-alanine, nitrate) provide modest performance benefits. Nutrient timing around exercise optimizes fueling and recovery.