NutritionAnswer

HOW DO I AVOID BONKING ON LONG RIDES?

By Anthony WalshRoadman CyclingUpdated 26 May 2026

ANSWER

Avoid bonking by starting to fuel within 30–45 minutes of setting off — before you feel empty — and targeting 60g of carbohydrate per hour on any ride over 90 minutes. Once glycogen is depleted, you cannot fully recover mid-ride. Set a recurring alarm on your head unit, carry more food than you think you need, and eat by the clock, not by hunger. The bonk is not bad luck; it is a fuelling failure that is entirely preventable.

KEY TAKEAWAYS

Start eating at 30–45 minutes, not when you feel flat — by then you are already two gels behind.
Target 60g/hr of carbohydrate for rides over 90 minutes as the dependable baseline.
Once glycogen is depleted you cannot fully recover mid-ride — prevention is the only strategy.
Carry more food than you think you need; run out of food once and you will always over-pack.

WHO THIS IS FOR

IS THIS YOU?

The rider who has bonked before

You have experienced the bonk — the sudden loss of power, the fuzzy head, the desperate search for a café. You never want it again.

The cyclist starting to ride longer distances

You are stepping up to 3+ hour rides for the first time and want to get the fuelling right before the wheels fall off.

THE ROADMAN VIEW

Anthony has bonked on long rides and documented the experience. The description is always the same: you feel fine, then you feel fine, then suddenly you feel terrible, your power drops off a cliff, and you are reduced to survival pace while every ride companion disappears. The bonk is not gradual. It arrives suddenly because glycogen depletion is a threshold event.

The reason it keeps happening to riders who 'know' they should eat is that the hunger signal lags catastrophically behind actual glycogen needs. By the time you feel the bonk coming — that hollow, powerless feeling — your muscles are already operating in a deficit that food cannot quickly reverse. You can eat after the bonk and feel marginally better, but you cannot restore hard-riding capability mid-ride. The window to prevent it closed 30 minutes ago.

The alarm on the head unit is Anthony's practical solution and it works. Set a 20-minute recurring alert and eat something on each buzz regardless of how you feel. A gel, a banana, rice cakes, a bar — something with 30–45g of carbohydrate every 20 minutes keeps the tank above the critical level. On a 4-hour ride you will eat more than feels comfortable. Do it anyway.

EXPERT EVIDENCE

WHAT THE EXPERTS SAY

Dr Sam ImpeyWorld Tour nutritionist
Glycogen depletion is irreversible mid-ride without stopping and eating a full recovery meal — which is not an option in a race or sportive. The only strategy that works is prevention: consistent carbohydrate intake from the early stages, timed against the clock rather than against appetite or perceived effort.
Hear it: Why Pros' 120g Carb Rule Fails Amateurs | Roadman Cycling
Fuelling experiment — under vs optimal vs overRoadman podcast — controlled fuelling comparison
Under-fuelled riding produces a predictable pattern: power holds for 60–90 minutes, then declines steadily in the second half of the ride. The contrast with optimally fuelled riding is stark — the power curve stays flat where under-fuelling produces a visible fade. The experiment makes the prevention case more viscerally than any study.
Hear it: Under vs Optimal vs Overfueling on the Bike | Roadman Cycling Podcast

PRACTICAL APPLICATION

DO THIS WEEK

Set a 20-minute recurring alarm on your head unit
On any ride over 90 minutes, set a reminder to eat every 20 minutes from the 30-minute mark. Each alert is a prompt to take something with 20–30g of carbohydrate — a gel, half a bar, a banana, rice cakes. Three alarms equal roughly 60–90g per hour, which is the target.
Carry 20% more food than your plan requires
Calculate the food you need for your planned distance and add 20%. Longer routes, unexpected climbing, mechanical delays — anything can extend a ride. Running out of food is never acceptable when a few extra gels weigh nothing. Check your pockets before every long ride.
Front-load fuelling in the first hour
The first 90 minutes of a long ride is the window to defend glycogen levels before they begin to dip. Eating earlier — 30g at 30 minutes, another 30g at 50 minutes — is more effective than scrambling to catch up at 90 minutes. Start eating while you still feel fine.

COMMON MISTAKES

WHAT CYCLISTS GET WRONG

MISTAKEWaiting until you feel hungry or flat to start eating.
FIXHunger lags behind glycogen depletion by 20–30 minutes. Eat by the clock from 30 minutes in. By the time you feel the bonk, you are already too late.
MISTAKERelying on café stops as your only fuel plan.
FIXPlan café stops as supplements to on-bike fuelling, not replacements. The gap between café stops on a long ride often exceeds two hours — that is a 120g carbohydrate deficit if you carry nothing.
MISTAKENot practising fuelling on training rides.
FIXRace-day fuelling is not the time to learn what works. Practice your exact protocol — timing, products, and quantities — on training rides of similar duration to your event.

FAQ

FREQUENTLY ASKED QUESTIONS

What does bonking feel like?

A sudden, dramatic loss of power combined with mental fog, lightheadedness, and a sense of overwhelming fatigue. It comes on quickly — you can feel okay one minute and unable to hold 200 watts the next. The legs feel hollow and disconnected. Once there, riding hard is impossible until glycogen is partially restored.

Can you recover from a bonk mid-ride?

Partially. Eating immediately and reducing pace lets blood glucose recover over 20–30 minutes, which restores the ability to ride at easy pace. Full race-level power does not return until after a proper recovery meal. That is why prevention is the only real strategy.

How many gels do I need for a 100-mile sportive?

For a 100-mile sportive at around 5 hours of riding, targeting 60g/hr means 300g of carbohydrate. At 25–30g per gel, that is 10–12 gels — or a mix of gels, bars, bananas, and real food. Most riders carry 8 and run short. Carry 12 and eat most of them.

Does the bonk happen faster in the heat?

Heat increases metabolic rate, sweat losses, and perceived exertion — all of which can accelerate the path to glycogen depletion. Hot-weather rides require consistent fuelling from even earlier in the ride, with higher sodium intake alongside the carbohydrate.

Can I bonk on rides under 90 minutes?

Rarely, unless you were already under-fuelled before you started — poor diet the day before or no breakfast. Normal glycogen stores are enough for 60–90 minutes of moderate riding without on-bike food. For anything hard, long, or if you start under-fuelled, the window shortens significantly.

What is the fastest food to eat when you are bonking?

Fast-absorbing glucose: gels, energy chews, a sugary drink, or a banana. Solid food with fat or fibre delays absorption. In an emergency, a flat coke from a corner shop or a handful of sweets delivers glucose fast. Eat, slow down, and wait 20 minutes for it to take effect.

RELATED EPISODES

HEAR THE CONVERSATIONS

Under vs Optimal vs Overfueling on the Bike | Roadman Cycling Podcast

Why Pros' 120g Carb Rule Fails Amateurs | Roadman Cycling

Ben Healy's 140g/hr Fueling Strategy | Roadman Cycling