Carb Loading Guide: How to Carb Load for Endurance Performance | FTP Endurance Fuel
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How to Carb Load for an Endurance Event
The 48-hour plan that fills your glycogen stores before a marathon, sportive or triathlon — no depletion phase, no guesswork.
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How do you carb load? Eat 10–12g of carbohydrate per kilogram of body weight per day for the 24–48 hours before your event, keep fibre low, and don't panic about the scales — gaining 1–2kg of water weight means it's working. No depletion phase or exhausting workout is needed first.
What carb loading actually is
Your muscles store carbohydrate as glycogen — the fuel that powers race pace. Left to normal eating, those stores only cover roughly 90–120 minutes of hard effort. Carb loading tops the tank right up, so you start with the biggest possible reserve and put off the wall for as long as possible.
Forget the old-school protocol of running yourself into the ground and starving carbs for three days first. The modern approach is simple: no depletion phase. You just taper training and eat a lot more carbohydrate for one to two days. Same result, none of the misery.
How much do you need?
The target is 10–12g of carbohydrate per kilogram of body weight per day. For a 70kg athlete that's 700–840g of carbs a day — far more than it sounds. A big bowl of pasta is only around 70–80g, so hitting the number takes deliberate effort: white rice, bread, jam, fruit juice, sports drinks and easy snacks like energy pastilles between meals.
Keep fibre low while you do it. Swap wholegrain for white versions, ease off the vegetables and pulses for 48 hours, and your stomach will thank you on the start line. Low-fibre, carb-dense options do the heavy lifting here — two FTP pastilles carry roughly 30g of carbs with barely any chewing time.
| When | Carb target | What it looks like |
| 48h before | 10–12g/kg · start the load | Carbs at every meal — rice, pasta, bread — plus snacks and juice between meals; training tapered right down |
| 24h before | 10–12g/kg · keep it going | Same again, fibre kept low — white versions of everything, pastilles and sports drink to fill the gaps |
| Evening before | Familiar carb-based dinner | Nothing new, nothing spicy, nothing huge — you've done the loading already |
| Race morning | 1–4g/kg, 1–4h out | Low-fibre breakfast you've practised — porridge made with white oats, toast and jam, banana |
Yes, you'll gain weight — that's the point
Glycogen is stored with water, so a proper carb load typically adds 1–2kg on the scales. Don't let it rattle you. That extra weight is stored fuel and stored fluid — both of which you'll be very glad of at mile 20. Athletes who see the number climb and cut back on carbs are undoing exactly the preparation they set out to do.
Loading made easy
Two FTP pastilles ≈ 30g of low-fibre carbs. Graze your way to the target.
Mistakes that undo the load
Starting too late (the night-before pasta party alone won't fill the tank). Under-eating because the volume feels absurd — it should feel like a lot. Loading with high-fibre or fatty foods that leave you bloated. Trying brand-new foods in race week. And forgetting to drink: glycogen storage needs fluid, so keep the bottle going — you'll find our full hydration guidance on the hydration & electrolytes page.
Carb-dense, low-fibre, race-proven
Tart Cherry Energy Pastilles 1kg
A full loading block and race day covered from one pack.
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Mixed Fruit Energy Pastilles 1kg
Same carbs, mixed fruit flavours to keep grazing easy.
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Tart Cherry Taster Pack
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Try the TasterCommon Questions
How many days before a race should I carb load?
Start 24–48 hours out. One focused day at 10–12g/kg can be enough for shorter events; two days gives more margin for a marathon or long-course triathlon.
Will carb loading make me gain weight?
Temporarily, yes — expect 1–2kg, and treat it as a good sign. Glycogen is stored with water, so the gain is fuel and fluid, not fat, and it's gone within days of the race.
Do I need a depletion phase first?
No. The modern protocol skips depletion entirely — taper your training and eat 10–12g/kg for 24–48 hours. It fills glycogen stores without wrecking your legs in race week.
Is carb loading worth it for events under 90 minutes?
Generally not — normal glycogen stores cover roughly 90–120 minutes of hard work. Save the full load for marathons, sportives, long rides and triathlons.
Load properly. Race full.
Stock up on low-fibre, carb-dense FTP pastilles before race week arrives.
Shop Energy PastillesKeep reading: Carbohydrate Loading for Running · What to Eat During a Marathon · How Many Carbs Per Hour? · Fuel for a Marathon
