Carbohydrates in cycling: how many do you need per hour?

Most cyclists fuel incorrectly. Not because they eat too little. But because they eat the wrong ratio — and because they try to get everything from one source. 60g of glucose per hour is a hard ceiling. Every extra gram gets stuck in your gut. Cramps. Bloating. Lost the last climb.

The solution isn't a brand. It's a system: 2:1 glucose/fructose, distributed between sports drinks and bars. This guide explains how many carbohydrates cycling requires per hour, why 60g is the ceiling without fructose, and how to fuel up to 90g/hour through a realistic combination without stomach problems.

Why carbohydrates are the only fuel that matters in cycling

During exertion above 70% of your maximum effort, your body primarily burns carbohydrates. Fat is too slow. Protein is irrelevant during the ride. Glycogen — the stored form in muscles and liver — is depleted after 60 to 90 minutes of intense riding.

What happens then has a name: glycogen depletion. Your wattage drops. Your heart rate remains high but your power plummets. Cyclists call this "hitting the wall". Sports science calls it a bottleneck in energy supply.

Exogenous carbohydrates — fuel you consume during the ride — are therefore not a luxury on rides longer than 75 minutes. It's about saving the ride or losing the ride. Eagle Nutrition builds the fruit performance bar precisely for this moment: during exercise, as part of your fueling strategy.

How many carbohydrates do you need per hour during cycling?

The recommended intake depends on the duration and intensity of the ride. Research by Asker Jeukendrup — one of the most cited sports scientists in endurance nutrition — provides these guidelines:

Ride duration	Carbohydrates per hour	Main source
< 60 min	0g (not needed)	water
60–120 min	30–60g	sports drink sufficient
120–180 min	60–75g	sports drink + 1 bar/hour
> 150 min, high intensity	up to 90g	sports drink + 1–2 bars/hour

60 versus 90 grams. That difference is not a gradation. It's a completely different absorption architecture in the gut.

What is the difference between 60g and 90g of carbohydrates per hour?

The difference lies in the number of active transport channels in the small intestine. Glucose is absorbed via one protein: SGLT1. Its maximum capacity is approximately 60g of glucose per hour. Taking more doesn't work — it won't be absorbed faster. The glucose remains in the gut.

However, there is a second transport protein: GLUT5. This transports fructose via a completely separate channel. By combining glucose and fructose in a 2:1 ratio, you use both channels simultaneously. Result: up to 90g of carbohydrates per hour are absorbed without overloading the gut.

This is not a claim. Research by Currell & Jeukendrup (2008) showed that a 2:1 glucose-fructose mixture improved time trial performance by 8% compared to glucose alone. King et al. (2019) later confirmed that 90g/hour is the optimum — above that, performance deteriorates. Rowe et al. (2022) reported a 7.6% gain on a 5 km time trial plus significantly fewer stomach complaints.

Every Eagle Nutrition fruit performance bar is built around this 2:1 ratio. No additives. Architecture.

How do you practically divide 60 to 90g of carbs per hour?

You never get carbs from a single source during exercise. Always from a combination. Pros and experienced cyclists use a standard system: sports drink as the primary source, bars as a solid component, gels optionally as a final boost.

The reason is practical and physiological. Sports drink provides carbs and fluids simultaneously — the two things your gut needs to absorb anything at all. Bars provide texture, a feeling of satiety, and mental variation during a long ride. No one can chew a bar every 15 minutes for four hours. No one should even try.

Standard sports drinks contain 6 to 8% carbohydrates. This is an isotonic concentration — the same osmotic pressure as your blood, thus maximum absorption rate. Specifically, this means:

• 500 ml sports drink (6–8%) = 30 to 40g carbs
• 750 ml sports drink (6–8%) = 45 to 60g carbs
• 800 ml 2:1 high-carb mix = up to 60g carbs per bottle

One Eagle fruit performance bar provides 20g of carbs in the same 2:1 ratio. Together, you build your hourly schedule this way. No magic. Just math.

How many bars and how much drink per hour? The Eagle fuel matrix

Practical distribution for each ride category:

Goal per hour	Sports drink	Eagle bars	Extra
60g (ride 2–3h)	1 bottle 500–750 ml (40–50g)	1 bar (20g)	—
75g (long ride, high pace)	1 bottle 750 ml (50–55g)	1 bar (20g)	—
90g (granfondo, 3h+)	1 bottle 800 ml 2:1 mix (60g)	1–2 bars (20–40g)	final gel optional

Maximum 1 to 2 Eagle bars per hour. More is not physiologically realistic — your stomach cannot digest four bars per hour during exercise, and you also don't have time to eat them at wattage. Bars are not a substitute for drinks. They are a supplement.

For a 4-hour granfondo at 75g/hour, you plan: 4 bottles of drink (or 2 bottles with 2x refills) + 4 to 6 bars over the entire ride. Plan this in advance. Never improvise on the bike.

Why do so many cyclists get stomach problems with a lot of carbohydrates?

Unabsorbed glucose attracts water into the gut. Those who consume 90g of pure glucose per hour overload SGLT1. Half of it remains undigested. Osmotically, this unabsorbed sugar draws water towards the intestinal wall. Result: cramps, bloating, in extreme cases diarrhea on the bike.

Stomach problems are one of the main reasons why cyclists underperform in the last hour of a long ride. Not too few carbs. Too much of the wrong type, or too much from one source.

Fructose structurally bypasses this problem. It uses GLUT5 — completely separate from the glucose pathway. The shared absorption load via two channels demonstrably reduces the chance of gastrointestinal stress. That's what makes the 2:1 ratio functional: it's not about fueling faster. It's about being able to keep fueling. That's why Eagle has that ratio in the bar and why you should also look for it in your sports drink.

When do you start fueling during a long ride?

Start drinking and eating within the first 20 minutes of the ride — even if you feel good. Waiting until you are hungry is too late. By then, a quarter of your glycogen stores are already gone. Catching up won't work.

Rules of thumb for a ride longer than 3 hours:

• From minute 0: consistent drinking from a bottle, a sip every 10–15 min
• Minute 15–20: first bar, 20g carbs
• Then every 30–45 min: one bar, maintain rhythm
• Refill bottle: every 60–90 min, depending on temperature and sweat
• Scale up intensity: at higher wattages, your total intake goes towards 90g/hour

A 25g bar fits in your back pocket, in a bottle cage, in a triathlon suit. The texture is deliberately soft — not a brick you have to wash down, not a gel consistency that turns your stomach. Edible during exercise. Period.

Fruit performance bar versus energy gel: what works better during exercise?

Most bars in the store are built as snacks — full of fat, protein, and fiber that slow stomach emptying. Exactly what you don't want on the bike. Energy gels go the other way: pure concentrated sugar without texture, often without a 2:1 ratio, and frequently synthetic.

A fruit performance bar sits in between — but functionally:

Factor	Energy gel	Standard bar	Eagle fruit performance bar
Carbs per serving	20–30g	15–25g	20g
Glucose/fructose ratio	often not 2:1	usually none	2:1
Fat/protein as inhibitor	low	high	low
Synthetic ingredients	regularly	often	0%
Texture during exercise	sticky	dry / brick	soft, chewable

Gel or bar? No choice. A bar provides texture and satiety that a gel cannot deliver. A gel is useful for one peak moment in the final. For consistent fueling over hours, the drink + bar combination works better — gentler on the stomach, more sustainable in energy.

No gel. No brick. Fuel. That's the category.

Does the 90g rule also apply to runners and triathletes?

Yes. Gut physiology is sport-agnostic. SGLT1 and GLUT5 work identically for a cyclist on a climb as for a triathlete on the bike-to-run section. 60g per hour is the ceiling with glucose alone. 90g per hour is the ceiling with 2:1.

The only difference is practical. Runners experience more gastrointestinal movement due to the impact of running — a shaking stomach is more sensitive. The 2:1 ratio reduces this sensitivity by distributing the load over two channels. Triathletes calculate the same 60–90g/hour for their bike leg and plan to refuel again in the first 15 minutes of the run.

Eagle Nutrition focuses on cycling, MTB, gravel, running, and triathlon. One bar. One formula. Four sports. One principle: during exercise, clean, 2:1, in combination with your sports drink.

Conclusion: carbohydrates cycling in one rule

60g per hour with glucose only. 90g per hour with the 2:1 ratio, distributed over sports drink and 1 to 2 bars. Start within the first 20 minutes. Consistent fueling until the end. That's the complete fueling strategy for any ride longer than 90 minutes. The rest is execution.

Eagle Nutrition fruit performance bars are built around this exact principle. 20g carbs per bar. 2:1 glucose-fructose. Without artificials. Vegan, gluten-free, lactose-free. One to two per hour, as a solid component alongside your bottle. No stomach upset. Four flavors you can eat on the pedals.

Fuel correctly. Fuel your flight.

View the fruit performance bars →