Sports Nutrition Basics
Fueling for performance: carb timing, protein for recovery, hydration during exercise, and supplements that work.
TL;DR
- 01Carbohydrates are the primary fuel for moderate-to-high intensity exercise — under-eating carbs impairs performance more than almost any other single factor.
- 02Consuming 20–40 g of protein within 2 hours post-workout maximizes muscle protein synthesis; total daily protein (1.6–2.2 g/kg) matters more than exact timing.
- 03Of dozens of marketed supplements, only creatine monohydrate, caffeine, beta-alanine, and nitrates have strong evidence of performance benefit.
Tips
- 01Calculate your sports nutrition needs based on training load, not body image goals. An athlete trying to lose weight while training hard is working against recovery — periodize fat loss to lower-intensity training blocks.
- 02Distribute protein evenly across 3–5 meals rather than concentrating it in one sitting. Research shows spreading 160 g/day across 4 meals (40 g each) produces greater MPS than two meals of 80 g.
- 03Look for third-party tested supplements (NSF Certified for Sport or Informed Sport label) if you compete in tested sports — contamination with banned substances is a genuine risk with unverified products.
Warnings
- 01Hyponatremia (low blood sodium from drinking too much plain water) is a genuine risk in long events. Do not force-drink plain water beyond thirst in marathons or triathlons — use electrolyte-containing sports drinks for events over 2 hours.
Fueling for Performance
Sports nutrition is applied nutrition science aimed at maximizing athletic performance, accelerating recovery, and maintaining health under training stress. The three macronutrients each play distinct roles: carbohydrates fuel intensity, protein rebuilds tissue, and fat supports hormonal function and low-intensity endurance.
Daily calorie needs for athletes are substantially higher than for sedentary individuals. Underfueling — known as Relative Energy Deficiency in Sport (RED-S) — impairs performance, hormones, bone density, and immunity even before body weight drops noticeably.
| Sport type | Daily carbs (g/kg body weight) | Daily protein (g/kg) | Daily calories above sedentary TDEE |
|---|---|---|---|
| Recreational (3× per week, moderate) | 3–5 g/kg | 1.4–1.7 g/kg | +200–400 kcal |
| Endurance (5–10 hrs/week) | 5–7 g/kg | 1.6–1.8 g/kg | +500–800 kcal |
| High-volume endurance (10+ hrs/week) | 6–10 g/kg | 1.6–2.0 g/kg | +800–1,500 kcal |
| Strength/power sports | 4–6 g/kg | 1.8–2.2 g/kg | +300–600 kcal |
| Team sports (mixed intensity) | 4–7 g/kg | 1.6–2.0 g/kg | +400–700 kcal |
Carbohydrate Timing
Carbohydrates are stored as glycogen in muscle (~400 g) and liver (~100 g). Glycogen is the limiting fuel for exercise above 65% VO2max — when it depletes, performance drops sharply (the well-known "hitting the wall" in marathons). Strategic carbohydrate timing optimizes glycogen availability for key sessions.
- 3–4 hours before training: Full carbohydrate meal — 1–4 g/kg body weight. Includes oats, rice, pasta, sweet potato, bread. Include moderate protein (20–30 g) and limit high-fat or high-fiber foods that slow gastric emptying.
- 30–60 minutes before training: Small, fast-digesting carb — banana, white toast, sports gel (30–60 g carbs). Avoid fiber and fat at this stage.
- During exercise (>60–90 minutes): 30–60 g carbs per hour; up to 90 g/hour with trained gut for events over 2.5 hours. Use a glucose:fructose ratio of 2:1 to maximize intestinal absorption.
- Within 30–60 minutes post-exercise: 1–1.2 g/kg high-glycemic carbs to accelerate glycogen resynthesis, especially if training again within 8 hours.
| Timing | Carb amount | Good sources |
|---|---|---|
| 3–4 hrs pre | 1–4 g/kg (~80–300 g for 75 kg athlete) | Oats, rice, pasta, sweet potato |
| 30–60 min pre | 30–60 g | Banana, white bread, sports gels |
| During (per hour) | 30–90 g/hr | Sports drinks, gels, chews, dates |
| Post-workout | 1–1.2 g/kg | White rice, fruit, sports drinks |
Protein for Muscle Repair
Exercise causes micro-damage to muscle fibers. Muscle protein synthesis (MPS) — the repair and rebuilding process — is elevated for up to 48 hours after a resistance training session and requires adequate amino acids, particularly leucine as the primary trigger.
The optimal dose of protein per serving to maximally stimulate MPS is 20–40 g of high-quality protein containing ~2–3 g of leucine. Doses above 40 g do not further stimulate MPS in one sitting but still contribute to daily protein total.
| Protein source | Serving | Protein (g) | Leucine (g) | Notes |
|---|---|---|---|---|
| Chicken breast | 150 g cooked | 45 g | 3.5 g | High bioavailability; low fat |
| Whey protein (concentrate) | 1 scoop (30 g) | 24 g | 2.7 g | Fast-digesting; ideal post-workout |
| Casein protein | 1 scoop (30 g) | 24 g | 2.3 g | Slow-digesting; ideal pre-sleep |
| Eggs (whole) | 3 large | 18 g | 1.4 g | Excellent amino acid profile |
| Greek yogurt | 200 g | 20 g | 1.8 g | Also provides calcium |
| Lentils (cooked) | 200 g | 18 g | 1.3 g | Lower leucine; combine with other sources |
| Tempeh | 100 g | 20 g | 1.5 g | Complete plant protein; fermented |
Hydration During Exercise
Dehydration of just 2% of body weight measurably impairs endurance performance, cognitive function, and perceived effort. At 3–4%, strength and power drop. Sweat rate varies from 0.5 to 2.5 L/hour depending on intensity, environment, and individual factors — there is no universal hydration target.
The practical approach: drink to thirst during most exercise sessions. Thirst is a reliable guide for sessions under 60 minutes. For sessions over 90 minutes, especially in heat, use a structured hydration plan.
| Session type | Fluid recommendation | Electrolyte need |
|---|---|---|
| Under 60 minutes, cool | Drink to thirst; ~400–600 mL | None — plain water sufficient |
| 60–90 minutes, moderate heat | 400–800 mL/hour | 300–500 mg sodium/hour helpful |
| 90+ minutes, high intensity or heat | 600–1,000 mL/hour | 500–1,000 mg sodium + potassium/hour |
| Multi-stage events (days) | Monitor urine colour (pale yellow = adequate) | Full electrolyte replacement critical |
- Sodium is the most important electrolyte to replace in sweat — it maintains plasma volume and prevents dangerous hyponatremia (overhydration with plain water in long events).
- Pre-hydration: 5–10 mL/kg of fluid in the 2–4 hours before exercise.
- Post-exercise rehydration: Consume 1.25–1.5× the fluid lost (weigh before and after — each 1 kg lost ≈ 1 L of sweat).
Evidence-Based Supplements
The sports supplement industry generates billions in revenue with most products lacking rigorous evidence. A small number of supplements have consistent, replicated evidence of benefit. Prioritize food and training first — supplements offer marginal gains, not foundational ones.
| Supplement | Dose | Effect | Evidence |
|---|---|---|---|
| Creatine monohydrate | 3–5 g/day (no loading needed) | +5–15% strength and power output; increases muscle mass over time | Very strong — 300+ studies |
| Caffeine | 3–6 mg/kg body weight, 30–60 min pre-exercise | Reduces perceived effort; improves endurance and peak power | Very strong |
| Beta-alanine | 3.2–6.4 g/day (split doses to reduce tingling) | Buffers muscle acid; benefits sustained high-intensity efforts 1–4 minutes | Strong |
| Dietary nitrates (beetroot juice) | 400–600 mg nitrate, ~2–3 hours pre-exercise | Improves oxygen efficiency; most effective in recreational athletes | Strong |
| Whey protein | 20–40 g post-workout | Convenient complete protein to meet daily protein targets | Strong (as a protein source, not a magic supplement) |
| Vitamin D | 1,000–2,000 IU/day if deficient | Correcting deficiency improves muscle function and reduces injury risk | Moderate (benefit only if deficient) |
| BCAAs | N/A | No added benefit over adequate dietary protein | Weak — not recommended if protein targets are met |
| Glutamine | N/A | No performance benefit in healthy, well-nourished athletes | Very weak |
FAQ
Prioritize a carbohydrate-rich meal (60–100g carbs) paired with a modest amount of protein and minimal fat and fiber to keep digestion on your side. Practical options include oatmeal with banana and eggs, rice with chicken, or toast with peanut butter and fruit.
Drink 400–800 mL (roughly 14–28 oz) per hour during moderate exercise and scale up for heat or high sweat rates. For sessions longer than 60–90 minutes, add sodium via sports drinks or electrolyte tabs — plain water alone can dilute blood sodium and cause cramping or hyponatremia if you drink too aggressively.
The window is real but much wider than gym culture suggests — total daily protein intake (1.6–2.2 g/kg body weight) drives muscle gain more than hitting a narrow 30-minute window. That said, spreading protein across 3–5 meals of 20–40g each, with one close to your training session, is a practical approach that covers both bases.
The wall happens when muscle glycogen is nearly exhausted, forcing the body to rely on slower fat metabolism, causing a dramatic drop in pace. You can delay or avoid it by consuming 30–60g of carbohydrates per hour (gels, chews, or sports drinks) during any event or training run lasting longer than 75–90 minutes.
Creatine monohydrate is one of the most studied and safety-confirmed supplements available, with decades of research showing no harm in healthy individuals at standard doses (3–5g daily). It works best for sports and activities involving repeated short, high-intensity efforts — strength training, sprinting, and team sports — with minimal benefit for pure endurance events.