● PILLAR GUIDE

Race Day Nutrition Planning for Triathletes

10 min read 8 sections Nutrition

Nutrition is where most triathletes leave time on the course. A missed gel at the right moment costs you thirty minutes by the run. This guide breaks down nutrition strategy for every distance — from sprint to full Ironman — so you arrive at the start knowing exactly what, when, and why you are eating.

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The golden rule: nothing new on race day

Every gel, bar, electrolyte drink, or food item you plan to consume on race day must have been tested repeatedly in training at race-effort intensity. Your digestive system under endurance stress is not the time to discover that a particular brand causes nausea or that your stomach cannot tolerate that much carbohydrate per hour.

This applies equally to your race morning meal, your fuelling strategy during the race, and your recovery fuel immediately after. Consistency and predictability trump novelty every time.

Pre-race carbohydrate loading (48 hours before)

For any triathlon distance longer than an Olympic (90 minutes), carb loading in the 48 hours before the race has a measurable effect on performance. The goal is to maximize muscle glycogen storage while minimizing gastrointestinal stress.

Aim for 8–10g of carbohydrate per kg of body weight across the 48 hours before the race. This is higher than normal but not extreme — for a 70 kg athlete, this is roughly 560–700g of carbs per day. That translates to extra portions of pasta, rice, bread, and potatoes at each meal.

Reduce fibre intake: avoid raw vegetables, wholegrains, and legumes from 48 hours out.

Reduce fat and protein: these slow digestion and compete with carbs for intestinal space.

Increase carb proportion at breakfast, lunch, and dinner.

Avoid alcohol entirely: it interferes with glycogen synthesis and sleep quality.

The pre-race meal (3–4 hours before start)

Your race-day breakfast should be familiar, easily digestible, and predominantly carbohydrate. Aim for 100–150g of carbohydrate, moderate protein, and low fibre. Eat 3–4 hours before the swim so digestion is well underway by the time you start.

Common examples: porridge with banana and honey, toast with peanut butter and jam, rice cakes with jam, or a bagel with almond butter. If your stomach is especially sensitive, a high-carb sports drink can substitute for a solid meal.

Carbohydrate: 100–150g (porridge, toast, rice, bagel).

Protein: 15–30g (yogurt, eggs, peanut butter) — sufficient but not excessive.

Fibre: minimal (white bread, not wholegrain; no raw fruit).

Fat: minimal (avoid fried foods and high-fat toppings).

Hydrate with water, not excessive quantities — drink to thirst.

Nutrition for sprint distance (up to 90 minutes)

Sprint triathlons are short enough that you do not need to eat during the race. However, hydration is critical. Aim to drink 400–800 ml of water or sports drink depending on conditions and sweat rate.

If your race is particularly hot or you have a slow expected finish time (over 90 minutes), aim for 30–60g of carbohydrate during the race — delivered via sports drink or a single gel taken after the swim.

Hydration: 5–10 ml per kg of body weight per hour (roughly 400–700 ml).

Carbohydrate: optional; focus on hydration if under 90 minutes.

Take one gel at the start of the run if your race exceeds 75 minutes.

Nutrition for Olympic distance (120–150 minutes)

Olympic distance is the transition point where race fuelling becomes important. You need to begin eating on the bike, not waiting until you feel depleted. Aim for 30–60g of carbohydrate per hour on the bike, delivered via gels, bars, or sports drinks.

On the run, reduce fuelling slightly — aim for 20–40g per hour, usually delivered via gels, sports drink, or energy chews, depending on what you can tolerate at race effort.

Bike: start fuelling by km 10–15; take gel every 30–40 minutes.

Bike carbs: 30–60g per hour (two gels per hour, or a bar plus hydration).

Run: begin nutrition within the first 5 km (do not wait until you feel empty).

Run carbs: 20–40g per hour (one gel every 30–40 minutes on the run).

Hydration: drink to thirst, but aim for 400–800 ml per hour depending on conditions.

Nutrition for 70.3 distance (180–240 minutes)

70.3 is where nutrition becomes the primary performance variable. Most athletes need 60–90g of carbohydrate per hour on the bike and 30–60g per hour on the run. Dehydration and glycogen depletion are the main reasons athletes fall apart in the second half of the run.

Start fuelling within the first 15 minutes of the bike and never allow yourself to feel genuinely hungry. A feeling of mild nausea or heaviness in the stomach is normal and actually a sign you are fuelling adequately.

Bike: start fuelling by km 15; consume carbs every 20–30 minutes.

Bike carbs: 60–90g per hour (three gels, or gels plus sports drink).

Bike hydration: 500–1000 ml per hour depending on sweat rate and temperature.

Run: begin within first 5 km of the run; take gel every 20–30 minutes.

Run carbs: 30–60g per hour; switch to liquid calories (cola, sports drink) if solid fuel causes nausea.

Practice your exact race nutrition plan in three or more long training sessions before race day.

● Race Preprr

Map each gel, bottle, and nutrition cue directly onto your course in Race Preprr so you can see the exact km where each intake point falls. For a 90 km bike, knowing your gels hit at km 15, 30, 45, and 60 removes decision-making on race day.

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Nutrition for full Ironman (480–600+ minutes)

Full Ironman nutrition is the ultimate endurance puzzle. Most athletes consume 60–90g of carbohydrate per hour on the bike and 30–60g per hour on the run, but individual tolerance varies widely. Some athletes with highly trained guts can tolerate 100–120g per hour.

The critical rule is consistency. You do not experiment at hour four of a nine-hour race. Your nutrition should be on autopilot, with aid stations and cues pre-planned to the kilometre.

Bike: start fuelling by km 15; consume carbs every 20–30 minutes.

Bike carbs: 60–90g per hour; adjust based on your training experience with high-carb fuelling.

Bike hydration: 400–800 ml per hour — drink to thirst but do not overdo it.

Run: begin nutrition within the first 5 km.

Run carbs: 30–60g per hour for the first half; consider dropping to liquid calories (cola) in the second half if solid food causes nausea.

Special needs bags: use these to carry preferred nutrition and any items (blister kit, socks) you might need mid-race.

● Race Preprr

For a full Ironman, map every single nutrition cue in Race Preprr. If your bike takes 5 hours and you take a gel every 30 minutes, that is ten gels. Knowing they hit at km 15, 25, 35, etc., makes the bike feel manageable instead of infinite.

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Managing nutrition when things go wrong

Despite perfect planning, race-day nutrition can fail. Your stomach may not tolerate what worked in training, aid stations may be short on your preferred brand, or you may have dropped nutrition into a water crossing.

Have a plan B ready before race day. For most athletes, the fallback is switching to liquid calories (sports drink, cola, juice) if solid gels cause nausea. This maintains carbohydrate intake and is often easier to consume when your stomach is upset.

Plan B for nausea: switch from gels to cola or sports drink.

Confirm alternate brands are available at aid stations.

Carry one backup gel in case you drop nutrition.

If you are seriously struggling, reduce fuelling to maintenance (just enough to not bonk) rather than your original aggressive target.

Remember: finishing is the goal; fuelling perfectly is secondary.

● Try it free

Map your race nutrition in Race Preprr
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Plan each gel, hydration point, and carb target on your course so your nutrition strategy is executed, not improvised. Free during public beta.

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