"Eat 60 g carbs per hour" is the half of fueling. The other half is timing — what you eat 30 minutes before matters as much as what you eat on the bike. This generator gives you a minute-by-minute plan for the pre-load, the ride, and the post-recovery window, plus a caffeine schedule that won't leave you wired at midnight.
| Time | Event | Carbs | Caffeine | Note |
|---|
The body's glycogen stores hold ~500 g. A 3-hour hard ride uses roughly 250-300 g. So you need to eat roughly half what you burn, and the rest comes from glycogen depletion — which is why you bonk at hour 2.5 of an unfuelled ride.
Timing isn't optional. Your body absorbs carbs fastest when blood glucose is slightly elevated and you're 30-60 minutes into exercise. That's the prime window. Loading too late means the carbs arrive after your gut has slowed down; loading too early means you're digesting during the warm-up instead of the work.
You can — but you'll likely under-fuel the first hour and over-fuel the third, and your gut will hate you. The point of a plan isn't to constrain you; it's to remove the "what do I eat now" decision while you're already working.
Studies show diminishing ergogenic benefit above ~3 mg/kg, and increased side effects (jitters, GI upset, post-ride crash) above 6 mg/kg. Anything beyond 9 mg/kg has no proven benefit and clear downsides.
Adjust the start time to your race start, not your wake-up time. The plan is anchored to the first gel.
Real food (rice cakes, bananas) works but is bulkier and harder to time precisely. Gels give you a known dose. Most long-distance riders mix — real food for steady state, gels for high-stress race moments.
This calculator was built to answer a question most online versions skip or oversimplify. It runs entirely in your browser; no inputs are stored or transmitted. The math is grounded in standard cycling physics and physiology models, and is suitable for hobbyist and intermediate training use. It is not a substitute for a coach, sports scientist, or professional bike-fit service.
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