Fuelling & performance nutrition for cycling

An evidence-based guide to fuelling the cyclist's body. Cycling is, like running, a story about a single fuel — muscle glycogen — and about not running out of it on a long ride. But it comes with a gift most endurance sports don't: you can eat and drink while you go, comfortably, for hours. This covers daily carbohydrate, the pre-ride meal, how much to take in on longer rides and races, carbohydrate loading, hydration by your own sweat rate, training your gut, recovery, and the quietly serious risk of chronic under-fuelling in lean riders. Practical, honest, and grounded in established sports-nutrition consensus.

Here's the short answer to "how should a cyclist fuel?": build the base with enough daily carbohydrate, top up before you ride, take in carbohydrate and fluid on rides longer than about an hour — roughly 30–60 g of carbs per hour, rising toward 90 g for long rides and races — and refuel and rehydrate afterwards, all while eating enough overall to avoid running an energy deficit. The bike makes the "during" part easier than almost any other sport; everything below is the detail behind that sentence, and how to make it work for your body rather than someone else's.

Pair this with the cycling strength and conditioning guide for the training side — the off-bike strength work that improves economy, sprint power and the position you hold for hours.

A framing note before the numbers. Sports nutrition is well studied, but people differ enormously — body size, riding intensity, fitness, the weather, gut tolerance, sex and health status all shift what's right on the day. So this is written as can, tends to and around, never as a guarantee, and every specific figure is a population-level guide drawn from published consensus, not a personal prescription. It's general education, not medical or dietary advice, and it isn't a personalised plan.

Why cycling is a glycogen sport

Your body rides on a blend of two main fuels: fat and carbohydrate. Fat is almost limitless even in a lean rider, but it burns slowly; carbohydrate — stored as glycogen in muscle and liver, plus glucose in the blood — burns fast and cleanly, and it's the fuel that lets you push real watts. The catch is that carbohydrate stores are small. A typical trained cyclist holds only a couple of thousand kilocalories of glycogen, enough for very roughly 90–120 minutes of hard riding before it runs low.

The harder you ride, the more you lean on carbohydrate rather than fat. That's the whole reason fuelling matters more for a long ride than for a gentle spin: at race or tempo intensity you're spending glycogen quickly, and when the tank empties — the classic "bonk" or "hunger knock" that hollows out a rider's legs on the last climb of a big day — power collapses not because your muscles are damaged but because they've run out of their fast fuel. The entire fuelling strategy below exists to do one of two things: start with more glycogen, and top it up as you go so you reach the finish before the tank does. Cycling's advantage is that the "top it up as you go" part is unusually practical — more on that below.

Daily carbohydrate — the base

Ride-day fuelling only works if you show up with the tank reasonably full, and that comes from your everyday carbohydrate intake, matched to your training. The joint position on nutrition and athletic performance from the Academy of Nutrition and Dietetics, Dietitians of Canada and the American College of Sports Medicine sets out daily carbohydrate targets scaled to training load: around 5–7 g of carbohydrate per kilogram of body weight per day for a general or moderate program (about an hour a day), roughly 6–10 g/kg/day for the moderate-to-high volumes of a serious cyclist training one to three hours a day, and up to 8–12 g/kg/day for the very high volumes of a rider doing four to five hours of moderate-to-hard riding daily. The International Society of Sports Nutrition frames the same idea as a broad 5–12 g/kg/day band, with the top reserved for those training many hours a week at intensity.

The practical point is that these dials should move with your week. A big long-ride or interval day warrants more carbohydrate than an easy or rest day. Chronically eating at the low end while training hard is one of the most common ways cyclists end up flat, under-recovered and stuck — the base is too empty for the quality fuelling on top to matter.

Before the ride — the pre-ride meal

For an easy or short ride you often need nothing special. Before longer or harder rides, and before events, a carbohydrate-focused top-up helps ensure liver and muscle glycogen are high at the start — the overnight fast, in particular, drains liver glycogen, so a morning ride benefits from breakfast. Position stands describe a pre-exercise meal or snack of roughly 1–4 g of carbohydrate per kilogram of body weight, eaten around one to four hours beforehand — the larger amounts earlier when you have time to digest, the smaller amounts closer to roll-out.

The art is in tolerance, not just grams. Favour familiar, lower-fibre and lower-fat carbohydrate you've rehearsed in training — porridge, toast, a banana, a bagel, rice — because fibre and fat slow digestion and can sit heavily on a hard early climb. The golden rule of event morning is to try nothing new: the meal, the coffee, the timing should all be things your gut has already met on a long training ride.

On the bike — carbs per hour

This is where cycling nutrition earns its keep — and where the sport has a genuine edge. Once a ride pushes past roughly an hour, taking in carbohydrate during the effort helps maintain blood glucose and spares your limited glycogen, delaying fatigue. How much depends mostly on how long and how hard you'll be riding. The joint position stand and wider consensus give a duration-scaled ladder:

The jump from 60 to 90 g per hour hides an important piece of physiology. The gut can only move a single type of carbohydrate (like glucose or maltodextrin) across the intestinal wall at a rate that tops out near 60 g per hour — pour in more and it sits in your stomach, which is how you get the sloshing and gut distress riders dread on a long day. But glucose and fructose use different transporters, so combining them — typically in roughly a 2:1 glucose-to-fructose ratio — lets the body absorb and burn carbohydrate faster, up to around 90 g per hour. That's why modern high-carb gels, drink mixes and chews advertise a "2:1" or similar blend: it's not marketing, it's the transporter maths that lets a cyclist fuel aggressively on a long ride without the gut shutting down.

Here is where cycling differs from running. Because you're seated on a stable platform and the sport is low-impact, your gut isn't pounded the way a runner's is — which tends to make it easier both to eat solid food and to tolerate higher carbohydrate intakes on the bike. You also carry bottles and stuff your pockets, so you can sip and snack almost continuously rather than grabbing what an aid station hands you. That combination is why the top of the ladder is more reachable on a bike, and why a strand of recent research in trained cyclists has pushed intakes even higher — studies have compared roughly 120 g per hour (using a slightly fructose-heavier blend) against the established 90 g/h, finding that more carbohydrate can be oxidised when the gut is well trained. That frontier is for well-adapted long-course riders, not a starting point — but it underlines that the format of cycling lets you fuel more than most endurance athletes can.

Two practical notes. First, drinks, gels, chews and real food are interchangeable ways to hit the target — pick what your stomach and the ride support, and count the grams, not the format. Second, these are ceilings you build up to, not day-one targets. New riders and those on shorter rides should sit at the lower end; only long-course athletes need the top of the ladder, and only after training their gut to handle it (below).

Carbohydrate loading before long events

For events that last longer than about 90 minutes — a long sportive, a gran fondo, a road race, the hard stages of a tour — starting with maximally full glycogen stores can meaningfully delay fatigue. This is carbohydrate loading, and the science behind it goes back to the 1960s, when researchers showed that a glycogen-depleting effort followed by a high-carbohydrate diet could roughly double muscle glycogen — a phenomenon called supercompensation.

The old, brutal "depletion" protocols have been replaced by something far gentler. Contemporary guidance describes eating around 10–12 g of carbohydrate per kilogram of body weight per day for the 36–48 hours before the event, while simultaneously tapering training so you're not burning off what you're storing. There's no need to starve yourself of carbs first; simply loading up while resting the legs brings stores close to their ceiling. Expect the scale to rise a kilo or two — each gram of glycogen is stored with roughly three grams of water, so that gain is fuel and hydration, not fat, and it will help you on the day.

Fluid, sweat rate and hydration

Cycling generates a lot of heat, and sweating is how you shed it — which means you're always losing fluid, sometimes a lot, though the airflow of riding can hide just how much. Significant dehydration (losing more than roughly 2% of body mass as sweat) is associated with rising effort, higher heart rate and, in the heat, falling performance. The long-standing guidance from the American College of Sports Medicine's position on exercise and fluid replacement is to drink enough to keep body-mass loss under about 2% over a long effort, rather than to a rigid schedule.

There's no universal ml-per-hour number, because sweat rates vary enormously. Road cyclists commonly lose anywhere from about 0.5 to 2.0 litres per hour depending on heat, humidity, intensity and the individual. As a working guide, typical fluid intakes on the bike often fall in a band of roughly 500–750 ml per hour, but programs should be individualised. Conveniently, the bike carries your bottles for you, so hitting these numbers is far easier than on foot — the limiter is usually remembering to drink, not being able to. The most reliable way to find your own number is to weigh yourself before and after a long ride in representative conditions: each kilogram lost is roughly a litre of sweat, which tells you how much you're under-replacing and how much to aim for next time.

For rides beyond about an hour, and especially in heat, replacing some sodium (electrolytes) alongside fluid helps you hold onto what you drink and can reduce cramping in salty sweaters. Conveniently, the same drink mixes that deliver carbohydrate usually carry sodium too, so on the bike your bottle can do double duty as fuel and hydration.

Training your gut

Here's the piece most riders skip. Taking in 60–90 g of carbohydrate an hour while riding hard is a skill the gut has to learn, not a switch you flip on event day. The intestine can be trained: regularly practising carbohydrate feeding during long rides appears to up-regulate the transporters that ferry glucose and fructose across the gut wall, speed up gastric emptying and dampen the sensation of fullness — so the same gels that make you queasy today are tolerated comfortably a few weeks from now.

The method mirrors training itself: start small and build gradually. Rehearse your exact event fuelling — the same gels, drink mix or bars, the same grams per hour, the same timing — on your long rides, nudging the hourly dose up over several weeks toward the intake you'll want on the day. Sports scientists who study this describe deliberately practising relatively high carbohydrate feeds (in the 60–90 g/h range, and higher for those chasing it) during training to raise tolerance. The payoff is twofold: your gut copes, and you arrive at the start line already certain your fuelling plan works. Nothing about event-day fuelling should be a first attempt.

Recovery — carbohydrate and protein

After a hard or long ride, two jobs matter: refill glycogen and repair muscle. How urgently you need to chase the first depends entirely on when you next ride hard.

• Fast turnaround (another hard ride within a day, a stage race, or twice-a-day training). Here speed matters. Research on rapid recovery describes taking in carbohydrate at around 1.0–1.2 g per kilogram of body weight per hour during the first few hours after riding to refill glycogen as quickly as possible — the muscle is most receptive to restocking soon after you stop. Adding some protein (roughly 0.25–0.3 g/kg per feed) supports repair, and appears to help glycogen refilling most when carbohydrate intake is on the low side. Stage racers live by this window.
• Normal turnaround (a full day or more until the next hard ride). There's no need to rush. Simply hitting your usual daily carbohydrate and protein targets across normal meals refills stores comfortably before you need them. The "eat within 30 minutes or lose your gains" urgency is real only when the recovery window is genuinely short.

Over the whole day, endurance cyclists are generally advised to eat around 1.2–2.0 g of protein per kilogram of body weight — more than a sedentary person, because hard riding damages muscle and protein supports repair and adaptation — spread across meals rather than piled into one. The eating-for-results guide covers the broader nutrition picture in depth.

Under-fuelling, bone health and RED-S

The most serious nutrition mistake in cycling isn't a bad gel choice — it's chronically eating too little to support the training. Riding burns a lot of energy and, combined with the sport's obsession with power-to-weight and low body mass (especially among climbers), it's one of the sports where athletes most often slip into low energy availability: not leaving enough energy, after riding is paid for, to run the body's basic functions.

Sports scientists quantify this as energy availability — roughly, energy eaten minus energy burned in exercise, expressed per kilogram of fat-free (lean) mass. Research associates falling below about 30 kcal per kg of fat-free mass per day with a cascade of problems, while something nearer 45 kcal/kg FFM/day is considered healthy for an exercising body. Sustained low energy availability is the root cause of what the International Olympic Committee calls Relative Energy Deficiency in Sport (RED-S): a syndrome, affecting both men and women, that can impair bone health, hormones and menstrual function, immunity, metabolism, mood and — the irony every rider chasing watts per kilo should note — performance itself. In women it commonly shows up as disrupted or absent periods; in men, as low hormone levels, low drive and stress fractures.

Cycling carries one extra wrinkle worth spelling out: it is a low-impact, largely non-weight-bearing sport. Because bone responds to loading and cycling gives it little, dedicated road cyclists already tend to have lower bone density than runners or team-sport athletes — so the bone-thinning effect of chronic under-fuelling lands on a skeleton that isn't being stimulated to stay strong in the first place. That makes protecting bone through adequate fuelling (and, for many riders, some off-bike resistance and impact work) doubly important in this sport.

The warning signs are worth knowing: recurrent or unexpected stress fractures, frequent illness, stalled or declining power despite hard training, poor sleep, low mood, and (in women) missing periods. None of these are things to push through. If they appear, the answer is usually to eat more, not train harder, and to seek help from a sports physician or dietitian. Fuelling isn't only about the big day — under-fuelling week after week is the fast route to injury, illness and burnout.

Common questions

How much carbohydrate should I eat per hour on a long ride?

It depends mostly on how long and how hard you're riding. Sports-nutrition consensus suggests little or no carbohydrate is needed for rides under about 45–60 minutes; around 30–60 g of carbohydrate per hour for efforts of roughly one to two-and-a-half hours; and up to about 90 g per hour for long rides and races beyond two-and-a-half to three hours. To take in more than about 60 g per hour you generally need multiple transportable carbohydrates — glucose plus fructose, often in roughly a 2:1 ratio — because a single sugar tends to max out near 60 g per hour. Because you sit on a stable platform, cyclists can usually eat more comfortably than runners, and some well-trained riders now practise even higher rates, but 90 g/h is a well-supported ceiling for most. Start low and rehearse it in training.

Can I really eat more on the bike than when running?

Generally yes, and it's one of cycling's real advantages. Riding is low-impact and you're seated on a stable platform, so your gut isn't jostled the way a runner's is, which tends to make it easier to eat solid food and to tolerate higher carbohydrate intakes. You also carry bottles and pockets of fuel with you and can sip and snack almost continuously. That's why the higher end of the carbohydrate ladder — around 90 g per hour, and higher in some trained riders — is more readily reached on a bike. The gut still has to be trained for it, and gut comfort still sets the limit, but the format works in your favour.

Do I need to carb-load before a long sportive or race?

For events lasting longer than about 90 minutes — a long sportive, gran fondo, road race or the hard days of a stage race — topping up muscle glycogen beforehand can help delay fatigue. Contemporary guidelines describe eating around 10–12 g of carbohydrate per kilogram of body weight per day for the 36–48 hours before the event, while easing off training. For shorter or easier rides, a normal high-carbohydrate day or two is usually enough and a full load is unnecessary. Expect a little scale weight gain, because glycogen is stored with water — that is normal and not fat.

How much should I drink while cycling?

There is no single number, because sweat rates vary widely — road cyclists commonly lose anywhere from about 0.5 to 2.0 litres per hour depending on heat, humidity, intensity and the individual. The long-standing sports-medicine guidance is to drink enough to limit body-mass loss to under about 2% over a long effort, rather than to a fixed schedule; typical intakes on the bike often fall in a broad band of roughly 500–750 ml per hour. The most reliable approach is to learn your own sweat rate by weighing yourself before and after a ride, then aim to replace most of what you lose. Drinking far more than you sweat is not safer and can be dangerous.

What should I eat before a ride?

For an easy or short ride you often don't need anything special. Before longer or harder rides, position stands describe a carbohydrate-focused meal or snack of roughly 1–4 g per kilogram of body weight, eaten around one to four hours beforehand — larger and earlier, or smaller and closer to the start, depending on what your stomach tolerates. Favour familiar, lower-fibre, lower-fat carbohydrate you've tested in training, and don't try anything new on event morning.

How should I refuel after a long ride?

If your next hard ride is soon — a back-to-back training day or a stage race — prioritise carbohydrate: research on rapid recovery describes intakes of around 1.0–1.2 g per kilogram of body weight per hour in the first few hours to refill glycogen quickly, plus some protein (roughly 0.25–0.3 g per kilogram) to support muscle repair. Adding protein seems to matter most when you can't get enough carbohydrate in. If you have a full day or more before the next tough ride, you don't need to rush — just hit your normal daily carbohydrate and protein targets across meals.

Takeaways

• Cycling is a glycogen sport. Its small carbohydrate stores are what limit hard and long rides, so fuelling is mostly about starting full and topping up.
• The bike lets you fuel as you go. Seated, low-impact and carrying your own bottles and food, you can eat and drink more comfortably than in most endurance sports — use that advantage.
• Build the base daily. Match everyday carbohydrate to training — roughly 5–7 g/kg on lighter days, up to 8–12 g/kg/day on the heaviest — and move the dial with your week.
• Top up before longer rides. A familiar, carb-focused meal of about 1–4 g/kg, one to four hours before; nothing new on event day.
• Fuel by duration on the bike. Little under an hour; ~30–60 g of carbs per hour for one to two-and-a-half hours; up to ~90 g/h beyond that, using a glucose–fructose (about 2:1) blend to absorb it.
• Carb-load for events over ~90 minutes. Around 10–12 g/kg/day for 36–48 hours while tapering; the water weight is fuel, not fat.
• Hydrate to your own sweat rate. Aim to keep body-mass loss under ~2%; road-cycling sweat rates run ~0.5–2.0 L/h and typical intakes ~500–750 ml/h, but weigh yourself to learn your number — and don't over-drink.
• Train your gut. Rehearse event fuelling on long rides so your gut tolerates 60–90 g/h; never debut a fuelling plan on event day.
• Recover with carbs (and some protein). Rush refuelling (~1.0–1.2 g/kg/h) only when the next hard ride is soon; otherwise normal meals suffice. Aim ~1.2–2.0 g/kg/day of protein overall.
• Eat enough, always. Chronic under-fuelling (low energy availability, RED-S) harms bone — a real concern in this low-impact sport — hormones, health and performance. When in doubt, eat more, not less.

If you remember one thing, make it this: the riders who fuel well aren't the ones with the fanciest gels — they're the ones who show up with a full tank, use the bike's rare gift of eating on the move to top it up sensibly for the distance, and eat enough overall to keep training. Strathlon's job is to keep that base honest by adjusting your targets around the rides you actually log, so the everyday fuelling that underpins every event is one less thing to guess at.

This is general educational information, not medical, dietary or coaching advice. The sports-nutrition figures here are drawn from established consensus and are framed as population-level guides — individual needs vary widely with body size, intensity, conditions, gut tolerance and health, and are best personalised with a qualified professional. Anyone with a health condition, a history of disordered eating, or who is pregnant or postpartum, or who suspects under-fuelling, stress fractures, menstrual disruption or RED-S, should consult a sports physician or registered dietitian before making changes. See our Terms for more.

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