Carbohydrates per hour in endurance sports: why 120g is the new golden standard
TL;DR: The old 60g-per-hour limit is outdated. Glucose alone saturates around 60g per hour, but with a 2:1 glucose/fructose ratio, you utilize two separate transport channels and can reliably reach 90g per hour. That is the proven norm. The build-up: sports drink as the main source, supplemented 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. First, establish your 90g. That's where your gains are.
How many carbohydrates per hour are achievable in endurance sports depends not on your legs but on your gut. For a long time, 60g per hour was considered the ceiling. That's true for glucose alone, but not for the right sugar mix. With a 2:1 glucose/fructose ratio, you can reliably reach 90g per hour. This article explains why, and how to get there safely. If you first want the full framework, read the complete guide to energy bars and endurance sports.
Why is the 60g-per-hour limit outdated?
Your small intestine uses two separate transport channels to move sugars from the intestinal wall into your blood. One channel processes glucose, the other fructose. The glucose channel saturates around 60g per hour. Any glucose above that remains in your intestine, attracts water, and causes cramps, diarrhea, or bloating. That is the true origin of the "60g limit": it's not a ceiling for your body; it's the ceiling for one channel.
Jeukendrup and Moseley demonstrated in 2010 that you break through that ceiling by adding fructose. Fructose uses its own route, separate from glucose. If you load both channels simultaneously, your total uptake increases without either route saturating. That's why 60g per hour is outdated as general advice: it only applies if you exclusively consume glucose. If you want to know why more and more cyclists are switching to clean carbs, read why cyclists are swapping gels for a clean label fruit energy bar.
Why is 90g per hour the proven norm?
Currell and Jeukendrup (2008) showed that a glucose/fructose mix not only provides more fuel but also improves performance: time trials were faster, and internal sugar reserves were spared. King and colleagues (2019) put the finishing touch on this. 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 worsened performance compared to 90g.
That makes 90g per hour the proven norm for the vast majority of endurance athletes. It is high enough to maintain your power in the last hour, and it fits within what a trained gut processes in a 2:1 ratio. My fruit performance bar delivers precisely that 2:1 ratio in a solid, doseable form: each bar weighs 25g and provides 20g of carbs, based on 80g of carbohydrates per 100g. The difference between drink and solid food is sharply evident in energy bar vs. energy gel: when to use what.
How do you practically assemble 90g per hour?
You won't get that 90g from bars alone. The basis is always a sports drink, supplemented with solid food. A sports drink with a concentration of 6 to 8% (about 500 to 800ml per hour) provides 30 to 60g per hour. On top of that, you add 1 to 2 fruit performance bars per hour, each providing 20g of carbs. Together, you easily reach 90g, with both transport channels active.
| Target carbs/hour | Sports drink (main source) | Fruit performance bars | For whom |
|---|---|---|---|
| 60g | ±40g (650ml, 6-8%) | 1 bar (20g) | Entry level, shorter rides, untrained gut |
| 90g | ±50g (800ml, 6-8%) | 2 bars (40g) | The proven norm for trained endurance athletes |
| 120g | Fructose-heavier mix (±1:0.8), gel in finale | 2 bars + extra fructose source | Elite, months of gut training, elite project |
Let's do the math for 90g: sports drink provides 50g per hour, two bars provide 40g, totaling 90g. Never three or four bars in an hour, as that overloads one texture and one source. The combination is what works. Your gut must also be trained to tolerate 90g. If you're still experiencing stomach problems, first systematically build up with a targeted approach for your bike ride.
Does 120g per hour really exist, or is it marketing?
120g per hour exists, but it is not standard advice and does not work with the 2:1 ratio. King and colleagues (2019) precisely showed that above 90g, the gain disappears: at 100g in a 2:1 ratio, performance decreased, not increased. Anyone who wants to reliably reach 120g per hour must shift the ratio to more fructose, approximately 1:0.8 instead of 2:1. Only then can the fructose route process enough extra sugar to lift the total.
And that comes at a price. 120g per hour requires months of specific gut training, a fructose-heavier mix, and an iron stomach. It is an elite project for professionals in a grand tour, not advice for a Saturday ride. The honest message: first establish your 90g. That's where your real gains are, and it is achievable for almost everyone.
What happens if you consume too few carbohydrates?
Underestimation is at least as costly as overestimation. Those who consume too little during intense exercise deplete their glycogen reserves faster and measurably lose power. Not because the muscles fail, but because the fuel supply falters. That's the classic "man with the hammer": your internal reserve drops, your blood sugar drops, your output drops.
Currell and Jeukendrup (2008) showed the mirror image: those who fuel with a glucose/fructose mix spare those internal reserves and maintain power longer. The benefit of proper fueling is not only in extra energy but also in protecting what you already have.
What role does the 2:1 ratio play exactly?
The 2:1 glucose/fructose ratio is not a marketing claim. It is the functional key beyond the 60g limit. Glucose and fructose use separate transport channels in your intestinal wall. By stressing both routes simultaneously, you double the effective throughput. With a 2:1 ratio, your processing can increase to about 1.5g per minute, or 90g per hour, without either channel saturating. The sugar concentration of your drink remains important: too concentrated slows gastric emptying and increases the risk of complaints.
I designed my fruit performance bar precisely on that principle. Each 25g bar delivers carbs in a 2:1 ratio, without artificials, without lactose, without gluten. This makes the bar a clean, doseable instrument alongside your sports drink. Not as a snack, but as fuel during exercise. The difference between clean and artificial is most sharply seen when you compare a fruit energy bar to classic sweets.
How do you safely build up to your hourly goal?
Your gut is a training variable. Anyone who tries 90g per hour on race day will lose that race in their stomach. Therefore, systematically build up during endurance training of at least 90 minutes, and adhere to four rules:
- Eat and drink on schedule. Don't wait until you're hungry. Hunger during exercise means you're already behind. Set an alarm. Fuel preventatively.
- Drink water or sports drink with every bar. Carbohydrate intake requires fluids. Dry intake slows absorption and increases the risk of stomach problems. At least 150ml with each bar.
- Never increase two variables at once. Either increase the amount, or the intensity. Doing both at the same time masks the cause of any complaints.
- Test your race setup exactly. Train with the same products, at the same intensity, in the same conditions. No new products on race day.
Above 75% of your VO2max, intestinal absorption slows down, so also train your intake at race intensity, not just on easy endurance rides.
No gel. No brick. Fuel.
The question is not whether you "may" consume 60, 90, or 120g per hour. The question is what your gut can handle and what you have systematically built up. 60g per hour is outdated as a ceiling. 90g per hour in a 2:1 ratio is the proven norm, and achievable for almost everyone with sports drink as a base and a clean fruit performance bar as a solid component. 120g per hour is an elite project, not a starting point. Establish your 90g. No gel. No brick. Fuel during exercise that still arrives at hour five. Fuel your flight.
Scientific basis
Your gut uses two separate transport channels for sugar absorption: 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 increases gastric emptying and absorption above the glucose limit. Currell and Jeukendrup (2008) showed that such a mix improves performance and spares internal sugar reserves. King et al. (2019) determined 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 worsened performance. Jeukendrup (2017) established that you train your gut capacity by systematically building up your carbohydrate intake during exercise. Doses towards 120g per hour require a fructose-heavier ratio (approximately 1:0.8) and extensive gut training, and remain reserved for trained elite athletes.
References
- 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 carbohydrates per hour can you absorb during endurance sports?
With glucose alone, the limit is around 60g per hour, because that transport channel saturates. In a 2:1 glucose/fructose ratio, you utilize a second channel and absorption reliably increases to 90g per hour. That is the proven norm for trained endurance athletes. Higher doses towards 120g per hour exist, but require a more fructose-heavy mix and months of gut training.
Is it true that the 60g-per-hour limit is outdated?
Yes, as general advice it is. The 60g limit only applies to glucose alone, because that single transport channel saturates. By adding fructose in a 2:1 ratio, you activate a second route and your total uptake reliably increases to 90g per hour, without either channel becoming overloaded.
Is 120g of carbohydrates 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 must shift the ratio to more fructose (approximately 1:0.8) and undertake months of specific gut training. For almost everyone, the real gain lies in a well-established 90g per hour.
How do you practically assemble 90g of carbohydrates per hour?
Sports drink is the main source: about 800ml in a 6 to 8% concentration provides approximately 50g per hour. On top of that, you add 2 fruit performance bars per hour, each providing 20g of carbs, totaling 40g. This way, you reach 90g with both transport channels active. Never consume three or four bars per hour; that overloads one source too much.
What role does a fruit performance bar play in high carbohydrate intake?
A fruit performance bar provides 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, doseable component: each 25g bar provides 20g of carbs, allowing you to fuel controllably towards 90g per hour without overtaxing your stomach.
