A century is a different animal to your weekend club run. Somewhere around the 70-mile mark, the ride stops being about your legs and starts being about your stomach. I've seen strong riders who can hold 250 watts all day come apart at mile 85 simply because they treated fuelling as an afterthought, nibbling a bar when they remembered and wondering why the wheels fell off. The truth is that pacing and nutrition are the two pillars of a successful 100-miler, and of the two, nutrition is the one most amateurs get badly wrong.
Learning how to fuel a century ride properly is the single biggest performance gain available to most riders, and it costs nothing but a bit of planning. Your body stores roughly 400-500g of carbohydrate as glycogen, which is enough for somewhere between 90 minutes and two hours of hard riding. A century takes most of us five to seven hours. The maths is brutal and simple: if you don't replace carbohydrate as you go, you will run out long before the finish. Here is how to make sure that doesn't happen.
Quick answer: to fuel a century ride, start eating within the first 30–45 minutes and take on 60g of carbohydrate per hour — pushing towards 90g per hour if you've trained your gut and you're using a glucose-fructose blend. Drink 500–750ml of fluid per hour with roughly 500–700mg of sodium per litre, and rehearse the whole plan on your long training rides so nothing is a surprise on the day.
Start Eating Before You Think You Need To
The most common mistake on a long ride is waiting until you feel hungry or tired before reaching for food. By the time you feel the first flicker of a bonk, your glycogen is already critically low and digestion has slowed because blood is being diverted to your working muscles. You are now trying to claw your way out of a hole rather than staying out of it in the first place.
Begin fuelling within the first 30 to 45 minutes, while your gut is still happy to absorb carbohydrate and your effort is comfortable. Set a timer on your head unit if you have to. The aim is a steady drip-feed of energy rather than occasional big feeds. Small, frequent amounts keep your blood sugar stable, sit more comfortably in the stomach, and mean you arrive at the hard final third of the ride with the tank still half full.
How Many Carbs Per Hour You Actually Need
For a steady century at endurance pace, aim for 60g of carbohydrate per hour. If you're riding hard, racing a sportive, or you've trained your gut to handle it, you can push towards 90g per hour, and the fastest riders now take in 100-120g per hour on the biggest days. But 60g is the sensible starting point and will see most riders through 100 miles in good shape.
The reason the elite numbers are possible at all comes down to the glucose-fructose ratio. Your gut can only absorb about 60g of glucose per hour through one transporter pathway (SGLT1). Fructose uses a separate transporter (GLUT5), so by combining the two sugars in roughly a 1:1 or 2:1 ratio you can shift 90g or more per hour without the surplus sitting in your gut and causing problems. This is why well-formulated sports nutrition blends glucose and fructose rather than relying on a single sugar. Practically, 60g per hour looks like one energy gel plus a few chews, or a bottle of carb drink and a handful of pastilles. Work out your hourly target, multiply by your expected ride time, and you'll know exactly how much to carry.
Don't Forget Fluid and Sodium
Fuelling isn't only about carbohydrate. On a warm day you can lose 500ml to over a litre of sweat per hour, and with it a significant amount of sodium. Dehydration of just 2% of body weight measurably reduces power output, and low sodium leaves you flat, crampy and slow even if your carbohydrate intake is spot on.
Aim for 500-750ml of fluid per hour, adjusting up in heat and down in the cold. Add sodium at roughly 500-700mg per litre, more if you're a heavy or salty sweater (you'll know because your kit dries with white tide marks). Alternating between a plain water bottle and an electrolyte bottle is a simple system that works. Crucially, practise drinking on the bike in training so that taking a bottle becomes automatic rather than something you forget for an hour at a time.
Put together, a century fuelling plan looks like this:
| Ride stage | What to do | Target |
| First 30–45 minutes | Start eating while the effort is comfortable — set a timer on your head unit if you have to | Begin the hourly drip-feed early, before any hunger |
| Every hour (fuel) | Small, frequent feeds: a gel plus a few chews, or a bottle of carb drink and a handful of pastilles (2 FTP pastilles ≈ 30g carbs) | 60g carbs/hour; up to 90g with a trained gut and a glucose-fructose blend |
| Every hour (fluids) | Alternate a plain water bottle with an electrolyte bottle; drink to a routine, not to thirst | 500–750ml fluid/hour with 500–700mg sodium per litre |
| Final third (miles 70–100) | Hold the schedule — this is where under-fuelled rides come apart | Maintain the same hourly carb and fluid targets to the finish |
Train Your Gut and Rehearse Your Plan
Your digestive system is trainable in exactly the same way your legs are. If you only ever practise eating 30g per hour, asking your stomach to process 60-90g on event day is a recipe for bloating, cramps and an unscheduled hedge stop. In the weeks before your century, use your long rides to rehearse your full fuelling plan: the same products, the same hourly amounts, the same timing. Nothing new on event day is the oldest rule in endurance sport, and it exists because people break it and pay for it.
Build a simple, repeatable routine. Decide what goes in which jersey pocket, work out how many items you need per hour, and know where the feed stops or shops are if you're relying on topping up en route. A century is far less daunting when you've already done a four-hour ride fuelling exactly the way you intend to race.
Build your century fuel kit
Glucose-fructose pastilles you can portion by the hour — two chews deliver roughly 30g of carbs.
What We Use at FTP Endurance Fuel
After years of fiddling with sticky gels and bars that turn to concrete in a cold back pocket, we built FTP Endurance Fuel around energy pastilles because they solve the practical problems of fuelling a long ride. They're easy to chew while holding a wheel, they don't require a hand free for tearing and squeezing, and they let you take small, precise amounts on a schedule rather than committing to a whole gel at once.
Our Mixed Fruit Pastilles use a balanced glucose-fructose blend so you can comfortably hit those higher hourly carbohydrate targets, while the Tart Cherry Pastilles add anthocyanins, the natural compounds in Montmorency cherries that help reduce the oxidative stress and muscle damage of a hard day in the saddle. The 1kg bulk packs work out far cheaper per gram of carbohydrate than single-serve sachets, which matters when you're getting through a lot of fuel across a big training block. If you've not tried them, the taster pack is an easy place to start before a long ride.
Frequently Asked Questions
How many carbs per hour do I need for a century ride?
Aim for 60g of carbohydrate per hour as the sensible starting point for a steady century. If you're riding hard or you've trained your gut, push towards 90g per hour using a glucose-fructose blend — the fastest riders now take in 100–120g per hour on the biggest days, but 60g will see most riders through 100 miles in good shape.
When should I start eating on a 100-mile ride?
Within the first 30 to 45 minutes, while your gut is still happy to absorb carbohydrate and the effort is comfortable. Waiting until you feel hungry or tired means your glycogen is already critically low — by then you're clawing your way out of a hole rather than staying out of it.
How much should I drink on a century ride?
Aim for 500–750ml of fluid per hour, adjusted up in heat and down in the cold, with sodium at roughly 500–700mg per litre — more if your kit dries with white tide marks. Alternating a plain water bottle with an electrolyte bottle is a simple system that works.
How do I avoid bonking at mile 80?
The bonk is glycogen depletion, and it's prevented hours earlier: start fuelling in the first 30–45 minutes, hold a steady drip-feed of 60g of carbohydrate per hour, and keep to the schedule through the final third rather than easing off when you feel good. Train your gut on long rides beforehand so those amounts sit comfortably at effort.
How to Fuel a Century Ride Without the Guesswork
Knowing how to fuel a century ride isn't complicated, but it does demand a plan you actually follow. Start eating early, target 60g of carbohydrate per hour and build towards 90g if you've trained for it, keep your fluid and sodium topped up, and rehearse the whole thing on your long rides so nothing is a surprise on the day. Get those basics right and you'll spend the final 20 miles riding strong rather than surviving. If you want simple, effective fuel that's easy to manage on the bike, take a look at our bundles and build your century kit before your next big day out.
Mixed Fruit Pastilles 1kg
A glucose-fructose blend built for higher hourly carb targets over 100 miles.
£44.99
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Electrolyte Tablets
Cherry-flavour tablets to keep your sodium topped up bottle after bottle.
£5.99
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