Nutrition

Pre-race nutrition is not one-size-fits-all. What works perfectly before a marathon — 800 kcal of oats and banana 3 hours before — would be excessive before a 5K. And attempting to eat a full meal 90 minutes before any race invites GI distress at the worst possible moment. The goal is to arrive at the start line with optimal glycogen stores and a settled gut. Here's how to do it for each distance.

The Physiology: Why Pre-Race Eating Matters

Overnight fasting depletes liver glycogen (which regulates blood glucose) by 50–80%. Muscle glycogen from the previous evening's carbohydrate intake remains relatively preserved, but liver glycogen must be topped up before hard exercise to prevent early hypoglycaemia and premature fatigue.

A pre-race meal serves two functions:

1. Restore liver glycogen to full after overnight fast
2. Top up muscle glycogen if carbohydrate loading in preceding days was insufficient

For races lasting under 60–75 minutes, glycogen depletion is not typically the limiting factor — but hypoglycaemia from skipping breakfast can impair performance even in short races.

The Carbohydrate-to-Time Relationship

The amount of carbohydrate appropriate before exercise depends primarily on how long before the start you're eating:

• 3–4 hours before: 2–4g carbohydrate per kg body weight. A full pre-race meal is possible and appropriate.
• 1–2 hours before: 1–2g carbohydrate per kg. Smaller, lower-fibre, lower-fat foods only. Gastric emptying time limits how much can be processed before exercise begins.
• 30–60 minutes before: 0.5–1g carbohydrate per kg. Small, rapidly-digesting carbohydrate only. A banana, a gel, a handful of dried dates.
• 15–30 minutes before: A single gel or 20–30g of rapidly-digesting carbohydrate. Some athletes experience reactive hypoglycaemia (a blood glucose drop) from eating in this window — practice in training before relying on it.

5K and 10K: Minimal Pre-Race Fueling Required

Races under ~45 minutes will not deplete glycogen regardless of starting stores. The primary goal is preventing hypoglycaemia — not maximising glycogen.

2–3 hours before a 5K or 10K: A moderate carbohydrate breakfast is sufficient. 200–300 kcal — toast with honey, a banana with nut butter, or a small bowl of oats. Avoid high-fat, high-fibre foods that slow gastric emptying.

Early morning 5K (warm-up is the race): A gel or banana 20–30 minutes before start. Don't force a full meal if race time doesn't allow digestion. A gel is enough to stabilise blood glucose for a 20–35 minute race.

Half Marathon: Moderate Pre-Race Fueling

A half marathon lasts 75–150 minutes. Faster runners (sub-90 minutes) are unlikely to fully deplete glycogen; slower runners (over 2 hours) need adequate starting stores and in-race fueling.

Protocol:

• Evening before: Normal carbohydrate-rich dinner. No need for aggressive carb loading.
• Race morning (3+ hours before): 300–500 kcal carbohydrate breakfast. Porridge, toast, banana — familiar and low-fibre. Avoid large amounts of fat, protein, or fibre.
• Race morning (1–2 hours before): If start is early, reduce to a smaller snack: a banana, a gel, rice cakes with honey.
• 30 minutes before: Optional 1 gel if stomach is settled and race is 90+ minutes.

Marathon: Full Pre-Race Nutrition Strategy

The marathon is the race where pre-race nutrition matters most. A sub-optimal breakfast directly affects the final 10km.

Protocol:

• 3 days before: Carbohydrate loading: 8–10g/kg/day. See our detailed carb loading guide.
• Race morning breakfast (3–4 hours before start):
  • 500–800 kcal of carbohydrates
  • 3–4g carbohydrate per kg body weight
  • Example for 70kg runner: 210–280g carbohydrates — large bowl of oats (60g) with banana (25g) and honey (15g), plus 2 slices toast (40g) with jam (30g), plus 400ml sports drink (30g). This is a significant meal.
  • Low fat, low fibre, no new foods
  • Include 400–600ml fluid
• 30 minutes before: 1 gel. Tops up blood glucose and provides final carbohydrate stimulus.

Managing Race-Morning Nerves and GI Sensitivity

Pre-race stress activates the sympathetic nervous system, which reduces gut motility and blood flow to the digestive system. This makes race mornings a poor time for gut experimentation. Strategies:

• Eat only foods you have practiced in training. Race day is not the time for new restaurants or new products.
• If appetite is absent due to nerves, liquid carbohydrates (sports drinks, smoothies) are easier to consume than solids.
• Eat early enough — the minimum 3-hour window between a full meal and race start is not arbitrary. It's the time needed for gastric emptying to reduce GI risk.

Building Your Race-Day Meal Plan

Use the NorthLine Pre-Race Meal Planner to generate a personalised meal schedule based on your race distance, start time, and body weight. The planner outputs specific gram targets for carbohydrates, timing for each meal, and food suggestions matched to the timing window before your event.