Cycling
Nutrition in the Saddle: Anti-Bonking Strategies
PUBLISHED: 2026-08-02|READ TIME: 4 MINS|AUTHOR: FRANCESCO CASTALDI
FIGURE: Cycling Nutrition Bars and Gels
What Really is the Bonk?
In Italian they call it "crisi di fame", in English "bonking" or "hitting the wall". It's not simple fatigue: it's the total depletion of glycogen (sugar) stores in muscles and liver. When you run out of glycogen, the body is forced to burn only fat, a very slow biochemical process. The result? A vertical drop in power. You can't exceed 15 km/h anymore.
The Math of Carbohydrates
Your body can only store about 2000 kcal in the form of glycogen (enough for 90-120 minutes at high intensity). If your ride lasts longer, you must fuel during the effort.
| Ride Duration | Carbohydrate Requirement | Recommended Sources |
|---|---|---|
| < 1 hour | None (water only) | - |
| 1 - 2 hours | 30g per hour | Bottle with maltodextrin or half a bar |
| 2 - 4 hours | 60g per hour | 1 Gel + Half isotonic bottle per hour |
| > 4 hours (Race) | 90-120g per hour | Glucose:Fructose Mix (1:0.8 ratio) |
[ TIP ]
The human body struggles to absorb more than 60g of glucose per hour due to the saturation of intestinal transporters (SGLT1). To reach 90g+, pros use specific mixes that include fructose (which uses another transporter, GLUT5).
Train to eat. Your gut must be "trained" to digest 90g of sugar per hour just as you train your legs. Don't try new bars or gels on race day!