Race nutrition by distance — 5K, 10K, half, marathon, ultra

5K. Glycogen is not limiting. Priorities: normal hydration the day before, a light pre-race meal 2–3 hours prior (50–75 g carb), caffeine 3–6 mg/kg 45–60 min pre-race for meaningful ergogenic effect. No in-race fuelling needed. Warm-up jogs can benefit from a carbohydrate mouth rinse (6.4% solution, swished 5–10 s, expectorated) if GI sensitivity is a concern — Chambers, Bridge & Jones (Journal of Physiology, 2009) demonstrated central-neural ergogenic effect via oral carbohydrate receptors even when no carbohydrate is swallowed.

10K and Half-Marathon. Full glycogen stores matter — 7–10 g/kg carbohydrate in the 24 hours prior. Pre-race meal 2–4 hours out (1–3 g/kg, low-residue). In-race fuelling at 30 g/hr becomes useful only if racing longer than ~75–90 minutes; elite 10K and fast HM runners do not need on-course fuel. Mid-pack runners racing a 2-hour-plus half-marathon benefit from 30–60 g/hr.

Marathon — the canonical case. 6-day modified loading culminating in 10–12 g/kg/day during the 36–48 hours pre-race. Race morning: 1.5–4 g/kg carbohydrate 3–4 hours before the gun (oatmeal + banana + honey + coffee is the classic). Optional 30 g top-up 10–15 min pre-start. On-course: 60–90 g/hr via gels, chews, or drinks with glucose + fructose, starting at km 6–8 before glycogen depletion becomes symptomatic. Caffeine: 3 mg/kg pre-race + optional 1–2 mg/kg at km 30. Hydration individualised from a sweat test, with sodium bolus (300–800 mg) in the final 10 km in hot conditions.

Ultramarathon (50K–100 miles). The game changes fundamentally. Hoffman and colleagues at the Western States 100 documented that elite 100-mile finishers consume 200–400 kcal/hr with significant rotation between sweet gels and savoury real food to combat palate burnout. Standard rotation: gels and sports drinks for the first 2–4 hours, transitioning to boiled potatoes with salt, rice balls with nori, pretzels, PB&J, chicken broth, bananas, pickles. Powdered calorie-dense drinks (Tailwind, Skratch Super High-Carb, Spring Energy Awesome Sauce) dominate because they bundle calories, electrolytes, and fluid. Gut training to 90–120 g/hr over 4–8 weeks is non-negotiable — stomach shutdown ("the pukies") is the most common cause of DNF after musculoskeletal failure.

Trail running. Weight per calorie matters in vertical terrain. Maurten gels (~1 kcal/g), Spring Energy pastes (~3 g carb per gram weight), and powder concentrates dominate. Higher sodium often needed (mountain heat + altitude). Chewable and drinkable options outrank solid real food on technical terrain — it is hard to chew while breathing at 160 bpm.

Multi-day stage races (Marathon des Sables, UTMB-style stages). Glycogen restoration between stages drives cumulative performance: 8–10 g/kg/day minimum, with post-stage 1.0 g/kg/hr in the first 4 hours. Freeze-dried calorie-dense meals, mandatory minimum calorie counts per race rules, and deliberate sodium pre-loading define the logistics.