Sports Nutrition Basics

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

Tip: Calculate 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.

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

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

Tip: Distribute 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.

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).

Warning: Hyponatremia (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.

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

Tip: Look 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.