What to Eat on a Ride to Avoid Bonking and Gut Issues

Your gut sets the fuelling ceiling as much as your legs do. To decide what to eat to avoid bonking during cycling, aim for around 60 grams of carbohydrate per hour as a practical starting point; under peak conditions, intake can reach 90 grams per hour. Start fuelling within the first 30-45 minutes rather than waiting for your energy to fade.

Taking on too much fuel at once can upset your stomach. A steadier plan is usually more manageable: take smaller amounts of carbohydrate regularly rather than trying to catch up with a last-minute rush.

This guide explains how much carbohydrate you may be able to digest, how to choose between gels, chews and drinks, and how to adjust your approach for ride duration and gut tolerance. You’ll also learn what to do if bonking symptoms start, so you can respond calmly and make a safer call about continuing.

1. What should you do if you bonk on a ride?

Bonking can cause a sudden loss of energy and fatigue as glycogen stores run low. If it happens, take in carbohydrate and fluid, then ease off instead of pushing through while fatigued.

For Australian cyclists, a practical guide is around 30-60 grams of carbohydrate per hour on rides lasting roughly 1 to 2.5 hours. Start fuelling within 30-45 minutes, then use a reminder every half hour to keep eating before fatigue hits.

A smaller, regular cue can work too: eat or drink a little every 20-30 minutes. Choose a schedule you can follow while riding, such as a reminder on your cycling computer or watch. The goal is consistent intake, not a large serving taken all at once.

On longer rides, carry enough food and water for the route. A formulated carbohydrate and electrolyte drink providing 60 grams of carbohydrate can be an alternative to gels and bars. It combines fluid and fuel in one option, which may suit riders who find eating difficult while moving.

If nausea makes solid food unappealing during a bonk, take carbohydrate with liquids. After eating, allow 15-20 minutes for the carbohydrates to take effect. Don’t continue pedalling in a compromised state; consider calling a friend or family member for a lift home.

If you’re helping another rider, guide them off the road to a safe spot, offer fast-acting sugar and stay with them while it takes effect. Don’t leave them to ride on alone while fatigue may affect their judgement or control.

Test your fuelling plan on training rides before race day. Try solid food, liquid fuel or a combination, and note which options feel manageable at your planned riding effort. Practising the timing as well as the food can help you spot gut issues early and adjust your routine before a long event.

2. Avoiding excess carbohydrates and stomach issues

More fuel isn’t automatically better. Your gut has limits, and suddenly increasing carbohydrate intake can cause discomfort. Plan food and fluid before the ride, then divide them into manageable portions instead of taking a large amount at once.

During cycling, the body can absorb up to 90 grams of carbohydrate per hour under peak conditions, though intake is usually closer to 60 grams. A general estimate for digestion while riding is 200-400 calories per hour. These figures describe different measures: carbohydrate intake is not the same as total calories digested.

For rides longer than 2.5 hours, carbohydrate intake can reach 90 grams every hour. That’s a high target, not a starting point for every rider. Build towards it through training, and remember that individual tolerance affects how much feels comfortable.

At higher intakes, the type of carbohydrate matters. For targets above 90g/hour, a glucose-and-fructose mix may be absorbed better than glucose alone. Spread intake across the hour and pair it with fluid according to your ride plan, rather than concentrating fuel into one large serving.

Set up your pre-ride nutrition well before departure. For a long or hard ride, eat a carbohydrate-focused meal 2-4 hours beforehand. Choose a portion that feels comfortable and familiar, with foods you’ve already tolerated before riding. A substantial meal too close to departure may feel harder to manage, so practise your timing during training.

To identify what triggers stomach issues, change one part of your plan at a time on training rides. Test the portion size, product type and timing separately, then record what you ate, drank and how your gut responded. If a higher intake causes discomfort, reduce the amount and build more gradually. A range of cycling nutrition options can help you trial different formats.

3. Emotional and physical symptoms of bonking

A cycling bonk is associated with depleted glycogen stores and often causes a sudden loss of energy or fatigue. The change can feel abrupt: your usual effort becomes difficult to sustain, and even familiar roads demand more concentration.

Physical signs can include a sharp drop in power and a heavy, exhausted feeling. Fatigue can also affect your mood and focus, making it harder to make sound decisions while riding. If your effort and alertness suddenly change, stop somewhere safe rather than pushing through.

Glycogen depletion doesn’t mean every store is completely empty. Even during a severe bonk, muscles retain between 10% and 30% of their original glycogen supply. That remaining fuel doesn’t make continued riding a safe choice when fatigue has affected your ability to control the bike.

Look at the pattern, not just one difficult patch. A steep climb can feel demanding without being a bonk; a sudden energy crash with marked fatigue is more concerning. Heat, pace and ride demands can affect how you feel, so stop safely and take stock rather than trying to identify the cause while moving.

Recovery can extend beyond the ride. After a hard effort, refuel with carbohydrate and some protein within an hour or two. Replenishing glycogen can take up to 24 hours, and recovery from a bonk usually takes at least a few days, sometimes longer. Suppressed immune function after a bonk can last from 24 to 72 hours after the ride.

Use your recovery to review the ride. Note when fatigue started, what you ate and drank, and whether your energy changed suddenly. Compare those notes with your next training ride, then adjust your fuelling routine before another long effort. Low-intensity rides can support adaptations associated with low glycogen without deliberately pushing yourself into a bonk.

4. Hydration and estimating sweat rate

Fluid needs vary with sweat rate, riding effort and conditions. To personalise your hydration plan, conduct a one-hour sweat-rate test during a moderate-intensity ride, then use the result to guide your planning.

Before the test, note the conditions and how much you drink. Ride at a steady, moderate effort for one hour, then record your fluid intake and how your body responded. Keep the route and effort similar when comparing future tests. This helps you account for differences between a hot, exposed ride and a cooler endurance session.

Cyclists typically sweat at a rate of 1-1.5 litres per hour during moderate cycling. That’s a useful reference, not a fixed drinking target: your own losses can vary with heat, effort and individual sweat rate. Plan water for the route, especially in hot conditions, and avoid relying on one estimate for every ride.

For rides shorter than an hour, water is generally all that’s needed. On longer rides, plan your fluids more carefully. A formulated carbohydrate-and-electrolyte drink combines fuel, fluid and electrolytes in one option, which may suit riders who’d rather not carry separate gels and bars.

How much should you drink while cycling, and when are electrolytes needed? Use your sweat-rate test to guide your fluid plan, and carry enough water for the ride, particularly in hot conditions. For longer rides, consider including an electrolyte-containing drink in your fuelling plan.

Build hydration into your route preparation: identify refill points, carry enough water for the distance, and review how the plan worked afterwards. If conditions become hotter than expected, reassess your supplies before continuing. A one-hour test gives you a more useful starting point than copying another rider’s routine.

Explore options for your ride fuelling plan and match your hydration approach to the demands of your next endurance ride.

Fastgear Australia

Fastgear Australia brings together endurance nutrition and racing gear to help riders build a practical fuelling setup. If you’re testing which formats fit your routine, options include GU Energy Gel – Single and Clif – BLOKS Energy Chews. Practise carrying and taking your fuel on training rides, then choose what suits your plan and gut tolerance.

The Compressport Free Belt Pro and Compressport Trail Racing SS Tshirt are also options for your ride kit. Focus on what you’ll use, and match your fuel choices to the timing and duration of your rides.

For help choosing from these options, contact Fastgear Australia.

Build a fuelling routine you can trust

Make your ride plan repeatable. Decide what to eat to avoid bonking during cycling, then practise your approach on familiar training routes. Keep a simple note of what feels comfortable, what’s easy to carry and what you’d change before your next longer effort. A routine suited to your gut and riding conditions is more useful than copying someone else’s setup.

Use your observations to prepare your kit for your next event. Choose fuel you can take consistently, and pack it where it’s easy to reach while riding. Small adjustments during training can help you start your next ride with a clearer plan and more confidence.

Contact Fastgear Australia about your cycling nutrition and gear, and get set for your next ride.

Frequently Asked Questions

How much fuel can you digest riding?

A practical estimate is 200-400 calories per hour while riding, but this isn’t the same as carbohydrate intake. Carbohydrate absorption is usually closer to 60 grams per hour and may reach 90 grams per hour under peak conditions. Ride duration, effort and gut tolerance all matter. Treat the upper figure as a target to build towards, not an amount to force in immediately.

What is bonking?

Bonking is a sudden energy crash associated with depleted glycogen stores, the body’s stored carbohydrate fuel. It can cause marked fatigue and make your usual riding effort difficult to sustain. It differs from simply feeling tired after a hard climb: an abrupt loss of energy is a signal to stop safely, take stock and respond rather than trying to ride through it.

What should you do if you bonk on a ride?

Stop somewhere safe, take in carbohydrate and fluid, and allow time for the fuel to take effect. If nausea makes eating difficult, pair food with liquids. Wait 15-20 minutes before judging whether you feel better, and don’t continue riding in a compromised state. Arrange a lift home from a friend or family member if fatigue is affecting your ability to ride safely.

What sort of food?

To decide what to eat to avoid bonking during cycling, choose carbohydrate you can take consistently: gels, chews, solid food or a carbohydrate drink. The right format depends on your gut tolerance and what’s practical while riding. For example, if solids are hard to manage, you may prefer sipping fuel; another rider might find chews easier. Test your options during training before relying on them on event day.

How many grams of carbohydrate per hour should cyclists eat to avoid bonking?

A practical starting point for what to eat to avoid bonking during cycling is 30-60 grams of carbohydrate per hour on rides roughly 1 to 2.5 hours long. For events longer than 2.5 hours, intake can reach 90 grams every hour. Build gradually and assess gut comfort during training. At 90g+/hour, a glucose-and-fructose mix may be absorbed better than glucose alone.

What should you eat before a long bike ride, and when?

Have a carbohydrate-focused meal 2-4 hours before a long or hard ride. A suggested range is 2 to 4 grams of carbohydrate per kilogram of bodyweight, depending on individual tolerance. Choose familiar foods and plan the meal around what you can comfortably eat before riding. Practise the timing and portion during training so event day doesn’t bring an unfamiliar meal or routine.