120 g of Carbs per Hour: Who Is It Actually For?
TL;DR: The old 60g per hour ceiling is outdated. Glucose alone saturates around 60g per hour, but with a 2:1 glucose/fructose ratio you use two separate transport channels and move reliably up to 90g per hour. That is the proven standard. The build-up: sports drink as your main source, topped up with 1 to 2 fruit performance bars per hour. 120g per hour exists, but it is an elite project with a more fructose-heavy ratio and months of gut training, not standard advice. Build your 90g solid first. That is where your gain is.
How many carbs per hour are achievable in endurance sport does not depend on your legs but on your gut. For a long time 60g per hour counted as the ceiling. That holds for glucose alone, but not for the right sugar mix. With a 2:1 glucose/fructose ratio you move reliably up to 90g per hour. This article explains why, and how you get there safely. Want the full framework first, then read the complete guide to energy bars and endurance sport.
Why is the 60g per hour ceiling outdated?
Your small intestine uses two separate transport channels to move sugars from the gut wall into your blood. One channel handles glucose, the other fructose. The glucose channel saturates around 60g per hour. Every gram of glucose above that stays in your gut, pulls in water and causes cramps, diarrhoea or a bloated feeling. That is the real origin of the "60g ceiling": it is not a ceiling of your body, it is the ceiling of one single channel.
Jeukendrup and Moseley showed in 2010 that you break through that ceiling by adding fructose. Fructose uses its own route, separate from glucose. Load both channels at once and your total uptake rises without either route saturating. That is why 60g per hour is outdated as general advice: it only holds if you take glucose alone. Want to know why more and more riders switch to clean carbs, then read why cyclists trade the gel for a clean fruit energy bar.
Why is 90g per hour the proven standard?
Currell and Jeukendrup (2008) showed that a glucose/fructose mix does not just deliver more fuel, it also improves performance: time trials got faster and the internal sugar store was spared. King and colleagues (2019) closed the case. They tested different doses over three hours of exercise and found that 90g per hour in a 2:1 ratio is the optimal dose. Important detail: more was not better. A dose of 100g per hour made performance worse than 90g.
That makes 90g per hour the proven standard for the vast majority of endurance athletes. It is high enough to hold your power in the final hour, and it fits within what a trained gut handles in a 2:1 ratio. My fruit performance bar delivers exactly that 2:1 ratio in a solid, dosable form: every bar weighs 25g and delivers 20g of carbs, based on 80g of carbohydrates per 100g. You see the difference between drink and solid food sharply in energy bar vs energy gel: when which.
How do you build 90g per hour in practice?
You do not get that 90g from bars alone. The base is always sports drink, topped up with solid food. Sports drink at a concentration of 6 to 8% (around 500 to 800ml per hour) delivers you 30 to 60g per hour. On top of that you add 1 to 2 fruit performance bars per hour, each good for 20g of carbs. Together you reach 90g easily, with both transport channels active. Plan it all properly with our Fuel planner tool.
| Target carbs/hour | Sports drink (main source) | Fruit performance bars | Who for |
|---|---|---|---|
| 60g | ±40g (650ml, 6-8%) | 1 bar (20g) | Entry level, shorter rides, untrained gut |
| 90g | ±50g (800ml, 6-8%) | 2 bars (40g) | The proven standard for trained endurance athletes |
| 120g | More fructose-heavy mix (±1:0.8), gel in the finale | 2 bars + extra fructose source | Elite, months of gut training, elite project |
Do the maths for 90g: sports drink delivers you 50g per hour, two bars deliver 40g, together 90g. Never three or four bars in one hour, because then you load one texture and one source too heavily. The combination is what works. Your gut also has to be trained to tolerate 90g. Still running into stomach trouble, then build up systematically first with a targeted approach for your ride.
Does 120g per hour really exist, or is that marketing?
120g per hour exists, but it is not standard advice and it does not work with the 2:1 ratio. King and colleagues (2019) showed precisely that above 90g the gain disappears: at 100g in a 2:1 ratio performance went down, not up. Anyone who wants to reach 120g per hour reliably has to shift the ratio towards more fructose, roughly 1:0.8 instead of 2:1. Only then can the fructose route handle enough extra sugar to lift the total.
And that comes at a price. 120g per hour demands months of specific gut training, a more fructose-heavy mix and a cast-iron stomach. It is an elite project for pros in a grand tour, not advice for the Saturday ride. The honest message: build your 90g solid first. That is where your real gain is, and it is achievable for almost everyone.
What happens if you take too few carbs?
Underdoing it costs you at least as much as overdoing it. Anyone who takes in too little during intense exercise runs through their glycogen store faster and loses measurable power. Not because the muscles fail, but because the fuel supply stalls. That is the classic "hitting the wall": your internal store drops, your blood sugar drops, your output drops.
Currell and Jeukendrup (2008) showed the mirror image: fuel with a glucose/fructose mix and you spare that internal store and hold power longer. So the gain of fuelling well is not only in extra energy, but also in protecting what you already have.
What exactly is the role of the 2:1 ratio?
The 2:1 glucose/fructose ratio is not a marketing claim. It is the functional key above the 60g ceiling. Glucose and fructose use separate transport channels in your gut wall. By loading both routes at once, you double the effective throughput. At a 2:1 ratio your processing can rise to around 1.5g per minute, meaning 90g per hour, without either channel saturating. The sugar concentration of your drink stays important here: too concentrated slows gastric emptying and raises the risk of complaints.
I designed my fruit performance bar exactly on that principle. Every 25g bar delivers carbs in the 2:1 ratio, without artificials, without lactose, without gluten. That makes the bar a clean, dosable instrument alongside your sports drink. Not as a snack, but as fuel during exercise. You see the difference between clean and artificial most sharply when you put a fruit energy bar next to classic sweets.
How do you build up safely to your target per hour?
Your gut is a training variable. Try 90g per hour for the first time on race day and you lose that race in your stomach. So build up systematically during long sessions of at least 90 minutes, and stick to four rules:
- Eat and drink on schedule. Do not wait until you are hungry. Hunger during exercise means you are already behind. Set an alarm. Fuel before you need it.
- Drink water or sports drink with every bar. Carbohydrate uptake needs fluid. Dry intake slows absorption and raises the risk of stomach trouble. At least 150ml with every bar.
- Never raise two variables at once. Raise either the amount or the intensity. Both at once masks the cause of any complaints.
- Test your exact race setup. Train with the same products, at the same intensity, in the same conditions. No new products on race day.
Above 75% of your VO2max gut absorption slows down, so train your intake at race intensity too, not only on easy long rides.
No gel. No brick. Fuel.
The question is not whether you are "allowed" 60, 90 or 120g per hour. The question is what your gut handles and what you have built up systematically. 60g per hour is outdated as a ceiling. 90g per hour in a 2:1 ratio is the proven standard, and achievable for almost everyone with sports drink as the base and a clean fruit performance bar as the solid component. 120g per hour is an elite project, not a starting point. Build your 90g solid. No gel. No brick. Fuel during exercise that still lands in hour five. Fuel your flight.
Scientific basis
Your gut uses two separate transport channels for sugar uptake: one for glucose, which saturates around 60g per hour, and one for fructose. Jeukendrup and Moseley (2010) described the mechanism by which a glucose/fructose mix raises gastric emptying and absorption above the glucose limit. Currell and Jeukendrup (2008) showed that such a mix improves performance and spares the internal sugar store. King et al. (2019) established 90g per hour in a 2:1 ratio as the optimal dose over three hours of exercise, with diminishing returns above that: 100g per hour made performance worse. Jeukendrup (2017) established that you train your gut capacity by building up your carbohydrate intake during exercise systematically. Doses towards 120g per hour demand a more fructose-heavy ratio (around 1:0.8) and extensive gut training, and remain reserved for trained elite athletes.
Sources
- Currell K, Jeukendrup AE (2008). Superior endurance performance with ingestion of multiple transportable carbohydrates. Medicine & Science in Sports & Exercise. doi:10.1249/mss.0b013e31815adf19
- Jeukendrup AE, Moseley L (2010). Multiple transportable carbohydrates enhance gastric emptying and fluid delivery. Scandinavian Journal of Medicine & Science in Sports. doi:10.1111/j.1600-0838.2008.00862.x
- King AJ et al. (2019). Liver and muscle glycogen oxidation and performance with dose variation of glucose-fructose ingestion during prolonged (3h) exercise. European Journal of Applied Physiology. doi:10.1007/s00421-019-04106-9
- Jeukendrup AE (2017). Periodized Nutrition for Athletes. Sports Medicine. doi:10.1007/s40279-017-0694-2
Frequently asked questions
How many carbs per hour can you absorb during endurance sport?
With glucose alone the limit sits around 60g per hour, because that transport channel saturates. In a 2:1 glucose/fructose ratio you use a second channel and move up to 90g per hour. That is the proven standard for trained endurance athletes. Higher doses towards 120g per hour exist, but they demand a more fructose-heavy mix and months of gut training.
Is it true that the 60g per hour ceiling is outdated?
Yes, as general advice it is. The 60g ceiling only holds for glucose alone, because that one transport channel saturates. By adding fructose in a 2:1 ratio you activate a second route and your total uptake rises reliably to 90g per hour, without either channel being overloaded.
Is 120g of carbs per hour achievable for the average athlete?
No. 120g per hour is an elite project. Research shows that above 90g in a 2:1 ratio the performance gain disappears. Anyone aiming for 120g has to shift the ratio towards more fructose (roughly 1:0.8) and do months of specific gut training. For almost everyone the real gain sits in a well-built 90g per hour.
How do you build 90g of carbs per hour in practice?
Sports drink is the main source: around 800ml at a concentration of 6 to 8% delivers roughly 50g per hour. On top of that you add 2 fruit performance bars per hour, each good for 20g of carbs, 40g together. That gets you to 90g with both transport channels active. Never take three or four bars per hour; that loads one source too heavily.
What role does a fruit performance bar play in high carbohydrate intake?
A fruit performance bar delivers 80g of carbohydrates per 100g in a 2:1 glucose/fructose ratio, without artificials, gluten or lactose. Alongside your sports drink it is a solid, dosable component: every 25g bar delivers 20g of carbs, so you fuel in a controlled way towards 90g per hour without overloading your stomach.
