How Many Carbs Per Hour for a Marathon? The 60–90 g Target

*This article was produced with sponsorship from DM Mitsui Sugar Co., Ltd.

How many carbohydrates should you take per hour during a marathon? The science is clear: 60–90 g per hour. Multiple studies and nutrition guidelines agree on this range※1※2. If you are chasing a personal record, it is a target you cannot skip.

Yet studies that measured what marathon runners actually take in found an average of only about 35 g per hour※3※4. That is roughly the carbohydrate in one or two gels.

That falls short even of the lower end of the target. Data on how much Japanese runners take in are scarce, but one survey of runners across all race distances found that about one in four took no fuel at all during the race※5.

This article explains why 60–90 g/h is the target and why so many runners fall short. It also shows how many carbohydrates you need for your finish time and gives you a race-day fueling plan.

This article focuses on fueling during the race and does not cover carb loading in the days before. For fluids and sodium, see the Marathon Hydration Guide.

Why Does Carbohydrate Intake Decide Your Marathon Time?

Legs that stop working late in a marathon have long been called “hitting the wall,” often around the 30 km mark (about 19 miles). The main cause is running out of stored carbohydrate, or glycogen, the form in which sugar is stored in your muscles and liver.

A 1986 study found that runners who slowed down late in the marathon had falling blood sugar levels and a sharp drop in how much carbohydrate they were using※6. Runners who did not slow down showed no drop in blood sugar.

The amount of fat burned stayed the same. Only the amount of carbohydrate burned suddenly fell. In other words, slowing down is caused not by being unable to use fat but by running short of carbohydrate.

When glycogen runs low, the muscle’s ability to contract also declines. A study using human muscle confirmed that when glycogen falls, the release of calcium inside muscle cells weakens※7. So you are not only low on energy; the muscle’s movement itself becomes sluggish.

A 2021 analysis of about 4 million marathon records shows how widespread this slowdown is※8. After 32 km (20 miles), 28% of men and 17% of women slowed down persistently. The study also linked this to starting too fast, which shows that a late-race slowdown is far from an exceptional event.

Conversely, taking in carbohydrates while running improves performance. In a laboratory study, time-trial performance was 19% better than with water alone. Using a drink with glucose and fructose in a 2:1 ratio instead of glucose alone made runners another 8% faster※9.

This is not only a story about recreational runners. A review of elite marathon nutrition strategies points out that carbohydrate stores can limit performance even for runners finishing in the 2-hour range※10. Holding a fast pace to the finish without fueling is hard for everyone.

How glycogen is converted into energy is covered in How Carbs Fuel Your Running: Carbohydrate Metabolism Explained, and the big picture of why carbohydrate intake matters is covered in Carbohydrates for Runners: Why They Matter and How to Fuel.

The Science-Backed Target: 60–90 g of Carbs Per Hour

Your Gut Has an Absorption Limit

Not every carbohydrate you swallow can be used as energy. There is a ceiling on how fast ingested carbohydrate can actually be used by your muscles. A 2000 review put that ceiling at about 1.0–1.1 g per minute, or 60–66 g per hour※11.

The bottleneck is thought to lie not in the muscles but in absorption in the gut (and processing in the liver).

That ceiling applies when you take glucose alone. Glucose is absorbed in the small intestine through a transporter called SGLT1 (a protein that carries sugar into cells), and this transporter saturates at about 60 g per hour※12. Anything beyond that is not absorbed and stays in the gut.

Mixing Carbohydrate Types Raises the Limit to 90 g/h

Fructose is absorbed through a different transporter, GLUT5※13. Because the route is different, fructose can still be absorbed even when the glucose transporter is saturated.

Taking both together raises total absorption to 90 g per hour. A review that systematically summarized carbohydrate use during exercise also lays out this mechanism※12.

A review that examined 14 studies found that a fructose-glucose mixture raised average power output by 1–9% compared with glucose alone※14. The recommended glucose-to-fructose ratio falls somewhere between 1:1 and 2:1.

What Is the Minimum Effective Dose?

So what is the minimum amount you need? A 2018 study tested this directly※15. It compared performance across four conditions of 0, 20, 39, and 64 g of carbohydrate per hour. Performance clearly improved in the 39 g and 64 g conditions, but the 20 g condition showed no meaningful difference.

In other words, about 40 g per hour is the minimum at which an effect appears. Because 39 g and 64 g produced almost no difference, glucose alone also appears to plateau near 40 g. Going beyond that requires combining carbohydrate types, as described above.

These experiments used cycling, but the way the gut absorbs carbohydrate does not depend on the sport, so the findings are thought to apply to running as well.

60–90 g/h Is Also the Official Recommendation

These numbers are not the claim of a few researchers. Nutrition guidelines compiled by the American College of Sports Medicine and others recommend 30–60 g per hour for 1–2.5 hours of exercise. For exercise longer than 2.5 hours, they recommend up to 90 g per hour using multiple types of carbohydrate※1.

A 2019 review of race nutrition for distance runners and race walkers also gives 75–90 g per hour as a guide for long events such as the full marathon※2.

Reviews since 2022 also discuss the possibility of raising the ceiling above 90 g※16. This is not yet a general recommendation, though, and the data are mostly limited to trail races and top athletes. For recreational runners, 60–90 g/h is the place to start.

Source	Exercise duration	Carbohydrate per hour
American College of Sports Medicine nutrition guidelines	1–2.5 hours	30–60 g
Same as above	Over 2.5 hours	Up to 90 g (multiple types of carbohydrate)
Race nutrition review for distance events (2019)	Long events such as the full marathon	75–90 g

Are You Taking Enough Carbs? Most Recreational Runners Aren’t

The target is 60–90 g/h. So how much are runners actually taking in? Several studies abroad have measured race-day intake.

In a 2025 survey of the Seville Marathon, the 160 participants averaged 35 g per hour※3. That is below even the lower end of the target. The study also found that runners who met 60–90 g/h were more likely to finish in under three hours than those who did not.

Another 2025 study weighed gels and drinks before and after the race to measure actual intake※17. Marathon runners planned on 25.9 g per hour but actually took in 21.7 g. They also tended to believe they had fueled as planned.

A study of 50 athletes competing in endurance events longer than 2.5 hours found that only 36% managed 60–90 g/h during the race※18. Even athletes who could correctly state the recommended amount averaged only about 56 g/h, so knowing the target does not simply translate into eating it.

A 2026 review also concludes that marathon runners’ reported carbohydrate intake during races averages around 35 g per hour※4. That is clearly lower than in cycling.

There is a large survey too. In a 2025 survey of 5,668 recreational marathon runners in China, only 57.2% practiced carb loading, and nearly half (49.1%) said they have no regular eating habits day to day※19.

What about Japan? I could not find a survey that measured recreational runners’ carbohydrate intake during races in grams. The closest is a 2021 survey that interviewed 171 participants of the Kaga Onsen-kyo Marathon※5.

In that survey, 28.0% of respondents, about one in four, said they take no nutrition during races. This figure covers participants across all race distances, including 10 km and shorter events, not the full marathon group alone. Energy jelly was used by 54.2%. Even among full marathon participants, only about half increased their staple foods (rice, bread, noodles) the day before.

Attitudes differed too. While 91.2% thought fluid intake during a race is important, only 77.2% thought nutrition during a race is important, so fluids were prioritized over carbohydrates.

A 2026 study of Japanese male athletes by sport found that long-distance runners’ median daily carbohydrate intake was 6.4 g per kg of body weight, somewhat short of the 6–10 g recommended for endurance athletes※20. They are not recreational runners, but the result hints at a tendency toward lower carbohydrate intake starting at everyday meals.

Specialist magazines for recreational runners have covered this problem as well. A feature in the April 2026 issue of the Japanese running magazine Runners reports, based on the editorial team’s own reporting, that “most runners take three or fewer energy gels in a full marathon”※21.

If one gel contains 20–25 g of carbohydrate, three gels supply 60–75 g over the whole race. For a runner who takes four hours, that works out to only 15–20 g per hour. That is half of the 35 g/h average measured abroad and far from the 60–90 g/h target.

A researcher who is also a sub-3-hour marathoner, featured in the same article, recommends taking more: “at least three, ideally six”※21.

Even I, though I was mindful of fueling, carried at most five or six gels in a full marathon. I thought that was enough, and I took one about every 30 minutes. When I ask other runners, many say three or four, and my impression is that few deliberately take more.

By my math, though, that falls short of the recommended 60–90 g/h.

Another reason is stomach trouble. Many runners deliberately cut back because they worry that taking more gels will make them feel sick. How to deal with that is covered in detail in Marathon Gel Strategy.

To sum up: the target is 60–90 g/h, the measured average for marathon runners abroad is around 35 g/h, and one Japanese survey covering all race distances found that about one in four runners took nothing during the race. For most runners, there is a lot of room to increase intake.

How to Plan Your Race Fueling From Your Goal Time

Calculate Total Carbohydrates for Your Finish Time

Your total need is the time you spend running multiplied by your hourly target. The table below shows the total carbohydrates needed for each finish time.

Finish time	60 g/h	75 g/h	90 g/h
3:00	about 180 g	about 225 g	about 270 g
3:30	about 210 g	about 265 g	about 315 g
4:00	about 240 g	about 300 g	about 360 g
4:30	about 270 g	about 340 g	about 405 g
5:00	about 300 g	about 375 g	about 450 g

For example, a runner finishing in 4 hours who aims for 75 g per hour needs about 300 g of carbohydrate over the whole race. At 25 g per gel, that is the equivalent of 12 gels.

In practice you also get carbohydrate from the sports drinks and food handed out at aid stations, so you do not need to carry 12 gels. But you can see that three or four gels falls far short.

For roughly the first 30 minutes, carbohydrate from your pre-race meal is still available, so there is no need to rush. Start taking carbohydrates at a steady pace once you pass the 5 km mark (about 3 miles), roughly 20–30 minutes in. Waiting until you feel hungry or sluggish is too late.

Then Dial In How You Take Your Gels

Once you know the amount you need, the question is whether you can actually take it. There are three key points. Choose a product that contains both glucose and fructose (a blend can support up to 90 g per hour). Take 150–200 mL (about 5–7 fl oz) of water with each gel. And take gels at even intervals of every 20–30 minutes, starting early in the race.

Taking a high amount for the first time on race day makes stomach issues more likely, so always test the same product, amount, and timing on a long run before the race. For why gels become harder to absorb and how to take them in practice, see Marathon Gel Strategy. For how to get your gut used to fueling, see Gut Training for Runners.

Summary

Simply knowing the 60–90 g/h target will change how you prepare for your next race. Start by working out the total you need from your finish time, gather enough gels that contain glucose and fructose, and try them out on a long run.

References

※1 Thomas DT, Erdman KA, Burke LM (2016) “American College of Sports Medicine Joint Position Statement. Nutrition and Athletic Performance” Med Sci Sports Exerc

※2 Burke LM, Jeukendrup AE, Jones AM, Mooses M (2019) “Contemporary Nutrition Strategies to Optimize Performance in Distance Runners and Race Walkers” Int J Sport Nutr Exerc Metab

※3 Jimenez-Alfageme R, Garrone FP, Rodriguez-Sanchez N, et al. (2025) “Nutritional Intake and Timing of Marathon Runners: Influence of Athlete’s Characteristics and Fueling Practices on Finishing Time” Sports Med Open

※4 Morton JP, Fell JM, Gonzalez JT, Hearris MA, Podlogar T, Pugh JN, Wallis GA (2026) “From Metabolism to Medals: Contemporary Perspectives and Revisiting Carbohydrate Guidelines for Fueling Endurance Athletes during Exercise” J Nutr

※5 田井勇毅, 真木瑛, 木戸康博 (2021) 「市民ランナーを対象とした食行動と食意識に関する調査」 [Dietary behavior and dietary consciousness among competitive amateur runners; in Japanese] 日本スポーツ栄養研究誌 (Jpn J Sports Nutr)

※6 Callow M, Morton A, Guppy M (1986) “Marathon fatigue: the role of plasma fatty acids, muscle glycogen and blood glucose” Eur J Appl Physiol Occup Physiol

※7 Ørtenblad N, Nielsen J, Saltin B, Holmberg HC (2011) “Role of glycogen availability in sarcoplasmic reticulum Ca2+ kinetics in human skeletal muscle” J Physiol

※8 Smyth B (2021) “How recreational marathon runners hit the wall: A large-scale data analysis of late-race pacing collapse in the marathon” PLOS ONE

※9 Currell K, Jeukendrup AE (2008) “Superior endurance performance with ingestion of multiple transportable carbohydrates” Med Sci Sports Exerc

※10 Stellingwerff T (2013) “Contemporary nutrition approaches to optimize elite marathon performance” Int J Sports Physiol Perform

※11 Jeukendrup AE, Jentjens R (2000) “Oxidation of carbohydrate feedings during prolonged exercise: current thoughts, guidelines and directions for future research” Sports Med

※12 Cermak NM, van Loon LJC (2013) “The use of carbohydrates during exercise as an ergogenic aid” Sports Med

※13 Fuchs CJ, Gonzalez JT, van Loon LJC (2019) “Fructose co-ingestion to increase carbohydrate availability in athletes” J Physiol

※14 Rowlands DS, Houltham S, Musa-Veloso K, Brown F, Paulionis L, Bailey D (2015) “Fructose-Glucose Composite Carbohydrates and Endurance Performance: Critical Review and Future Perspectives” Sports Med

※15 Newell ML, Wallis GA, Hunter AM, Tipton KD, Galloway SDR (2018) “Metabolic Responses to Carbohydrate Ingestion during Exercise: Associations between Carbohydrate Dose and Endurance Performance” Nutrients

※16 Podlogar T, Wallis GA (2022) “New Horizons in Carbohydrate Research and Application for Endurance Athletes” Sports Med

※17 Lanpir AD, Eroglu MN, Ozyildirim M, Louis J (2025) “Under Consumed and Overestimated: Discrepancies in Race-Day Carbohydrate Intake Among Endurance Athletes” Eur J Sport Sci

※18 Sampson G, Morton JP, Areta JL (2024) “A broken link: Knowledge of carbohydrate requirements do not predict carbohydrate intake around competition in endurance athletes” Eur J Sport Sci

※19 Chen Y, et al. (2025) “Nutritional status and practices among Chinese marathon runners: data from the China marathon nutrition survey (CMNS)” J Int Soc Sports Nutr

※20 Nakamura N, Ozawa S, Tokiwa S, Yamamoto K, et al. (2026) “Energy intake and expenditure of Japanese male soccer, long-distance running, and road cycling athletes across multiple teams” Phys Act Nutr

※21 『ランナーズ』 [Runners; in Japanese] April 2026 issue, feature 「エネルギージェル新常識」 [The new common sense about energy gels], R-bies Inc. (株式会社アールビーズ)