Is more carbohydrate better during exercise? What the evidence says about 90, 120 and 150 g/h
Oct 28
15 min read
Updated: 8 hours ago
For many years the guideline for carbohydrate intake during prolonged endurance exercise has been around 90 grams per hour, using a mix of glucose and fructose. More recently it has been suggested that 90 to 120 g/h could be beneficial in some situations, and in the meantime athletes have moved well beyond 120 g/h. Reports from professional cycling, triathlon, marathon running and ultra-endurance events describe intakes of 120 g/h and, in some cases, 150 to 200 g/h. Many athletes are left with the question how much carbohydrate do I need during exercise? A new study has now compared 90, 120 and 150 g/h directly (25). This blog is an update of an earlier post published in 2015 on the same question. The conclusions from that blog remain broadly accurate but needed revision to incorporate a number oif recent studies with carbohydrate intakes of 120 and 150 g/h. In this blog we will look at the evidence for higher intakes in more detail and separate fact from fiction.
How much carbohydrate during exercise do I need ?
What you need depends on a number of factors we will discuss here but for exercise more than 2.5h the recommendation is somewhere between 80 and 120 g/h, but we will discuss the nuances and details in this blog. There is a lot of confusion and misconception around carbohydrate intake during exercise. Some say that 90 g/h is a ceiling, but no research has ever suggested that. Others say that more is better, but no study has actually shown this. In fact, we have almost no performance studies that compared intakes above 90 g/h with each other. So, what evidence do people use to claim that more is better?
Intake rates are also frequently confused with oxidation rates. 90 and 120 g/h are intake rates, not oxidation rates. What you ingest and what you oxidise can be very different things.
What you ingest and what you oxidise can be very different things.
It is also not true that suggestions for higher intakes come from recent studies. Studies from 1999 used 180 g/h (1,2) and a study from 2004 used 144 g/h of mixed carbohydrates (3). These were published more than 20 years ago. What is new is that athletes have started using the science, not that the science itself is new. To get a clear picture we start with the question: where did the 90 g/h come from in the first place?
The early work on glucose fructose mixes
Carbohydrate oxidation from ingested drinks can be measured using stable istope technology (these methods are discussed in more detail in a separate blog). Before 2003, studies had shown that oxidation of a single carbohydrate, for example glucose or maltodextrin, was limited to about 60 g/h (4). This was observed across all studies and in the vast majority of individuals. In a couple of studies we gave as much as 180 g/h but only around 60 g/h was oxidised (1,2). We showed that the liver did not produce any glucose at these high intake rates (liver glycogen sparing), but of course glucose was accumulating somewhere in the body, and 120 of the 180 g/h went 'missing'. We started the search for the limiting factor. Our hypothesis was that glucose transport in the intestine was limited to about 60 g/h and that adding fructose, which uses a different transporter, might increase absorption.
In a study published online in 2004 we gave cyclists a large amount of glucose (72 g/h), an even larger amount of glucose (108 g/h) or a large amount of glucose with fructose (72 g/h of glucose plus 36 g/h of fructose) (5). We confirmed that adding more glucose had no effect on exogenous carbohydrate oxidation. However, for the first time we also demonstrated that adding fructose took oxidation rates well above 60 g/h. Peak oxidation was about 55% higher with the glucose and fructose drink (76 g/h) than with glucose alone (48 and 50 g/h). Over the 2 hours, 68% of the 108 g/h of glucose was not oxidised, against 49% with glucose plus fructose, and severe gastrointestinal discomfort was more common with glucose alone (5).
The follow up studies on glucose fructose mixes
In a series of follow-up studies we wanted to see how high we could go and which carbohydrate combinations gave the best results. Glucose with sucrose (6,7), maltodextrin with fructose (8) and a mix of glucose, fructose and sucrose (3) all gave higher oxidation than a single carbohydrate. The highest rate came with 144 g/h of the glucose, fructose and sucrose mix, which gave a peak oxidation of about 102 g/h, 44% higher than the same amount of glucose (3). The advantage was still there after 5 hours of exercise (9) and in the heat (10).
The advantage was not unconditional. At a moderate intake of 48 g/h, glucose plus fructose did not increase oxidation above that of glucose alone (11), which fits the idea that fructose helps once glucose transport is saturated. In women, peak oxidation of glucose did not rise further when intake went from 60 to 90 g/h (30 and 29 g/h) (12).
Did this translate into better performance? In a time trial after 2 hours of cycling, glucose plus fructose at 108 g/h gave an 8% quicker time than glucose alone (13). These drinks also emptied from the stomach faster and delivered more fluid (14). Later studies showed that high exogenous oxidation rates are seen when running as well as cycling (15) and with a gel or a bar as well as a drink (16,17). In 2010 we concluded that multiple transportable carbohydrates ingested at high rates can be beneficial in events lasting 3 hours or more (18).
Where does the 90 g/h figure come from?
Based on many studies and my observations with professional cyclists at the time, we recommended 90 g/h. This was not because it gave the highest oxidation rates, since 144 g/h had already given higher rates in 2004 (3). It was a practical choice. 90 g/h seemed to be the sweet spot between delivering carbohydrate and avoiding gastrointestinal problems. It was never presented as a ceiling, although wording such as 'up to 90 g/h' has probably encouraged that reading. It took many years before the higher intakes we recommended started to be adopted in endurance sports.
What do the current guidelines recommend?
The recommendations for carbohydrate intake during exercise depend on how long the exercise lasts. The 2016 joint position statement of the American College of Sports Medicine, the Academy of Nutrition and Dietetics and Dietitians of Canada (19) and a 2011 review by Louise Burke and colleagues (20) give the same ranges:
Less than about 45 minutes: carbohydrate is not needed during exercise (19).
About 45 to 75 minutes at high intensity: small amounts of carbohydrate or even a mouth rinse. The benefit appears to come from effects on the brain and not from fuel supply (19,20).
About 1 to 2.5 hours: 30 to 60 g/h. A single carbohydrate, such as glucose or maltodextrin, is sufficient because it can be oxidised at rates up to about 60 g/h (19-21).
More than about 2.5 to 3 hours: up to 90 g/h of multiple transportable carbohydrates, which means a mix such as glucose and fructose (19-21).
Two details are often forgotten. The advice is an absolute amount per hour and is independent of body weight and training status, and it may need to be adjusted downward when the exercise intensity is low and carbohydrate oxidation is therefore low (21). These guidelines were also written before the studies at 120 g/h and above that are discussed in the rest of this blog.
Where do the 120 to 200 g/h figures come from?
The higher intakes of 120 to 200 g/h came from a different kind of evidence. As athletes got used to higher intakes, the thinking became: more must be better. There were reports of Tour de France riders consuming more than 100 g/h, and some athletes reportedly trained to tolerate 200 to 220 g/h (22). The same review states that research has not yet substantiated the efficacy of these intakes and proposes that the upper limit could increase from 90 to 120 g/h in trained athletes, based on oxidation data. A second review, from another group, concludes that data do not consistently support dose-dependent performance benefits beyond 90 g/h (23). Initially there was no research to base the recommendations on, but more recently we have seen studies dedicated to these high intakes.
What did the new studies do?
In the second half of 2026 three new studies were published. Below I have summarise the key findings in these studies. The study by Ravikanti et al (24) is unique because it is in truly elite marathon runners and we did not have any exogenous carbohydrate oxidation data in the literature from elite athletes before this study. It shows that if they ingest more carbohydrate, more is oxidized similar to what was is expected based on existing data. It also showed more gastro-intestinal discomfort at higher intakes especially 120 g/h. The study did not measure performance. Martyn et al (25) studied performance with the intake of 90, 120 and 150 g/h, a long overdue study. They did not see a difference in performance between 90, 120 and 150 g/h, even though exogenous carbohydrate oxidation increased with increasing intake. The oxidation efficiency decreased. The third study by Norte et al (26) showed imporved performanc ewith 100 g/h versus 60 g/h. This is in line with an ealier study by Currell et al who showd that glucose fructose around 100 g/h improved performance compared with just glucose (of which less is oxidized). Most of these findings point towards a benefit of increasing carbohydrate intake to 80-120 g/h during exercise longer than 2.5h. The sweetspot is somewhere between 80 and 120 g/h with no evidence that higher intakes are better.
Most of these findings point towards a benefit of a carbohydrate intake of 80-120 g/h during exercise longer than 2.5h. The sweetspot is somewhere between 80 and 120 g/h with no evidence that higher intakes are better.
Three new studies summarised:
Ravikanti and colleagues (24) gave eight elite male marathoners (personal best about 2 h 23 min) 60 g/h of maltodextrin, 90 g/h of a 2:1 maltodextrin and fructose mix or 120 g/h of a 1:1 mix during a 2-hour treadmill run, with carbon-13 labelled glucose and fructose in the drinks. They reported exogenous oxidation of 53, 79 and 101 g/h. The oxygen cost of running was 3.6% lower at 120 g/h than at 60 g/h, and 1.5% lower than at 90 g/h. Moderate or severe gastrointestinal symptoms were common in all trials, and peak nausea, stomach fullness and cramps were highest at 120 g/h. The lower oxygen cost may not be an actual advantage as we will discuss below, and most of these findings would point towards a benefit of lowering carbohydrate intake to reduce gastrointestinal problems, not to increasing it to 120 g/h. Performance was not measured. The reported values for exogenous carbohydrate oxidation may be overestimations as we will discuss in a blog on the methodology.
Martyn and colleagues (25) performed a direct comparison of 10, 90, 120 and 150 g/h. Eight trained male cyclists rode for 3 hours, followed by a ride to exhaustion at 150% of lactate threshold, with all drinks in a 1:0.8 maltodextrin to fructose ratio. Mean exogenous oxidation was 74, 89 and 97 g/h at 90, 120 and 150 g/h. Whole-body carbohydrate oxidation was 138, 156 and 156 g/h, so 150 g/h gave no increase over 120 g/h. Oxidation efficiency, which is the percentage of the ingested carbohydrate that is oxidised, fell from 93% at 90 g/h to 86% at 120 g/h and 74% at 150 g/h. Total exercise time was 3 h 05 min at 90 g/h, 3 h 05 min at 120 g/h and 3 h 01 min at 150 g/h, so there was no difference in exercise capacity. Although a model placed the optimal intake for capacity at 107 g/h this estimate carries considerable uncertainty. With only eight participants and essentially identical exercise times across the top three doses, the model is fitting a maximum through a flat signal. The point estimate should not be taken as fact. The data are consistent with an optimum anywhere between 80 and 120 g/h, which also matches the dose-response flattening above about 78 g/h in the Smith study (28).
Norte and colleagues (26) gave 16 trained cyclists and triathletes 0, 60 or 120 g/h during 3 hours of cycling and then measured critical power with a 3-minute all-out test. Critical power fell by 14.7% with water, 7.4% with 60 g/h and 4.2% with 120 g/h. Mazza and colleagues (27) compared 60 and 100 g/h in 15 trained men who cycled for 4 hours with intermittent high-intensity efforts, in a double-blind crossover. A 15-minute time trial afterwards was 9.3% below the fresh value with 60 g/h and 6.4% below with 100 g/h, a difference of 9 W.
Does more carbohydrate improve performance?
The best dose-response study for performance, as summarised in two of the reviews (22,23), is that of Smith and colleagues (28). Fifty-one cyclists and triathletes rode for 2 hours at 95% of the workload that elicited a blood lactate concentration of 4 mmol/L and then completed a 20 km time trial, receiving between 10 and 120 g/h of a 1:1:1 glucose, fructose and maltodextrin mix. The model estimated performance improvements of 1.0, 2.0, 3.0, 4.0 and 4.7% at 9, 19, 31, 48 and 78 g/h, with diminishing returns above 78 g/h. Other studies summarised in the reviews found no differences between 60 and 112.5 g/h in a 30-minute time trial (23).
Most performance studies at high intakes compared a glucose and fructose mix with glucose alone at the same intake, and not one dose with another. Triplett and colleagues (29) gave nine cyclists 144 g/h and found that a simulated 100 km time trial took 204.0 min with glucose plus fructose and 220.6 min with glucose alone (p = 0.023). Currell and Jeukendrup (13) found that a time time trial at 108 g/h of glucose and fructose was improved 8% above glucose only and almost 17% compared with water. In a half-ironman race in 74 triathletes, a 2:1 glucose and fructose mix averaging 78.6 g/h gave a small benefit in race time of 0.53% compared with glucose only (30). These studies show the value of multiple transportable carbohydrates. They do not show that 144 g/h is better than 90 g/h.
The newer studies mentioned above measure something slightly different, which is endurance capacity. Norte (26) and Mazza (27) both found a smaller decline with 100 to 120 g/h than with 60 g/h. However in both of these studies the comparison is with 60 g/h and not with 90 g/h.
More on mechanisms
Mazza also found that muscle glycogen after the ride was similar between 60 and 100 g/h (192 and 209 mmol/kg dry weight), so the benefit was not explained by muscle glycogen sparing (27). Why might more carbohydrate help if it does not spare muscle glycogen? Studies have consistently shown sparing of liver glycogen and this is probably an important reason, but unlikely to be different for 90, 120 and 150 g/h.
Reviews propose three untested explanations: a shift towards carbohydrate oxidation that lowers the oxygen cost of exercise, enhanced lactate shuttling between tissues, and effects on the brain (23). A lower oxygen cost reflects a higher carbohydrate oxidation rate, but it is a mechanism and not a performance outcome, and the effect of carbohydrate on oxygen uptake is inconsistent across studies (23). Whether a lower oxygen cost, which is expected with a shift in substrate use towards carbohydrate, actually has an effect on performance, when oxygen availability is not limiting, is a big question that has not been answered. Faster runners use less oxygen to run at the same speed, but that is different because in that situation their energy expenditure is lower. When an athlete uses less oxygen as a result of an increase in carbohydrate use, their energy expenditure is unchanged, only the substrates change.
What is the evidence that more is better?
From 60 to 90 g/h: oxidation rises, and a glucose and fructose mix is needed above about 60 g/h. The performance evidence is a dose-response curve that flattens at around 78 g/h (28). More is better in this range, with diminishing returns. From 90 to 120 g/h: oxidation was higher at 120 g/h in all the studies that compared the two (24,25,31), but oxidation efficiency falls (24,25) and gastro-intestinal symptoms increase.
It is also worth mentioning that the absolute rates of exogenous carbohydrate oxidation in the newest studies are probably overestimations (32). The methods behind these numbers are discussed in a separate blog.
The evidence that more is better is therefore strong up to about 90 g/h, suggestive for 100 to 120 g/h against 60 g/h on endurance capacity, and absent for performance gains beyond 90 g/h in direct comparisons. At present, the claim that 120 to 200 g/h is better than 90 g/h rests on anecdotes, on oxidation measurements that are probably inflated, and on suggested mechanisms that nobody has tested. This is not evidence that it does not work. It is evidence that nobody has shown that it does.
Have the new studies changed the thinking? They have given us more robust data on exogenous carbohydrate oxidation at 90,120 and 150 g/h, and they have provided us with the first performance/endurance capacity data at these high intakes. They have not yet shown that intakes above 90 g/h improve performance, and the guidelines can only change when we have evidence that they do. Oxidation alone is not sufficient especially in the light of increasing gastro-intestinal discomfort.
Practical takeaways
For events longer than about 2.5 hours, 60 to 90 g/h from a glucose and fructose mix remains the best-supported range.
If an athlete wants to go above 90 g/h, 100 to 120 g/h is the range with supportive data.
Expect that about 20 to 30% of the carbohydrate you ingest at 120 g/h is not oxidised during exercise, and that this proportion rises with intake.
Do not go above 120 g/h on the basis of the current evidence. At 150 g/h whole-body oxidation did not increase and oxidation efficiency fell.
Rehearse the plan in training at race intensity and in race conditions, and drop back to 90 g/h if gastrointestinal symptoms limit your intake. How to train the gut for higher intakes was covered in a previous blog.
Treat the absolute oxidation numbers from the newest studies as upper estimates and compare doses within a study rather than across studies.
References
Jeukendrup AE, Raben A, Gijsen A, Stegen JH, Brouns F, Saris WH, Wagenmakers AJ. Glucose kinetics during prolonged exercise in highly trained human subjects: effect of glucose ingestion. J Physiol 515(Pt 2) 579-589, 1999.
Jeukendrup AE, Wagenmakers AJ, Stegen JH, Gijsen AP, Brouns F, Saris WH. Carbohydrate ingestion can completely suppress endogenous glucose production during exercise. Am J Physiol 276(4) E672-E683, 1999.
Jentjens RL, Achten J, Jeukendrup AE. High oxidation rates from combined carbohydrates ingested during exercise. Med Sci Sports Exerc 36(9) 1551-1558, 2004.
Jeukendrup AE. Carbohydrate intake during exercise and performance. Nutrition 20(7-8) 669-677, 2004.
Jentjens RL, Moseley L, Waring RH, Harding LK, Jeukendrup AE. Oxidation of combined ingestion of glucose and fructose during exercise. J Appl Physiol 96(4) 1277-1284, 2004.
Jentjens RL, Venables MC, Jeukendrup AE. Oxidation of exogenous glucose, sucrose, and maltose during prolonged cycling exercise. J Appl Physiol 96(4) 1285-1291, 2004.
Jentjens RL, Shaw C, Birtles T, Waring RH, Harding LK, Jeukendrup AE. Oxidation of combined ingestion of glucose and sucrose during exercise. Metabolism 54(5) 610-618, 2005.
Wallis GA, Rowlands DS, Shaw C, Jentjens RL, Jeukendrup AE. Oxidation of combined ingestion of maltodextrins and fructose during exercise. Med Sci Sports Exerc 37(3) 426-432, 2005.
Jeukendrup AE, Moseley L, Mainwaring GI, Samuels S, Perry S, Mann CH. Exogenous carbohydrate oxidation during ultraendurance exercise. J Appl Physiol 100(4) 1134-1141, 2006.
Jentjens RL, Underwood K, Achten J, Currell K, Mann CH, Jeukendrup AE. Exogenous carbohydrate oxidation rates are elevated after combined ingestion of glucose and fructose during exercise in the heat. J Appl Physiol 100(3) 807-816, 2006.
Hulston CJ, Wallis GA, Jeukendrup AE. Exogenous CHO oxidation with glucose plus fructose intake during exercise. Med Sci Sports Exerc 41(2) 357-363, 2009.
Wallis GA, Yeo SE, Blannin AK, Jeukendrup AE. Dose-response effects of ingested carbohydrate on exercise metabolism in women. Med Sci Sports Exerc 39(1) 131-138, 2007.
Currell K, Jeukendrup AE. Superior endurance performance with ingestion of multiple transportable carbohydrates. Med Sci Sports Exerc 40(2) 275-281, 2008.
Jeukendrup AE, Moseley L. Multiple transportable carbohydrates enhance gastric emptying and fluid delivery. Scand J Med Sci Sports 20(1) 112-121, 2010.
Pfeiffer B, Stellingwerff T, Zaltas E, Hodgson AB, Jeukendrup AE. Carbohydrate oxidation from a drink during running compared with cycling exercise. Med Sci Sports Exerc 43(2) 327-334, 2011.
Pfeiffer B, Stellingwerff T, Zaltas E, Jeukendrup AE. CHO oxidation from a CHO gel compared with a drink during exercise. Med Sci Sports Exerc 42(11) 2038-2045, 2010.
Pfeiffer B, Stellingwerff T, Zaltas E, Jeukendrup AE. Oxidation of solid versus liquid CHO sources during exercise. Med Sci Sports Exerc 42(11) 2030-2037, 2010.
Jeukendrup AE. Carbohydrate and exercise performance: the role of multiple transportable carbohydrates. Curr Opin Clin Nutr Metab Care 13(4) 452-457, 2010.
Thomas DT, Erdman KA, Burke LM. American College of Sports Medicine joint position statement. Nutrition and athletic performance. Med Sci Sports Exerc 48(3) 543-568, 2016.
Burke LM, Hawley JA, Wong SH, Jeukendrup AE. Carbohydrates for training and competition. J Sports Sci 29(Suppl 1) S17-S27, 2011.
Jeukendrup A. A step towards personalized sports nutrition: carbohydrate intake during exercise. Sports Med 44(Suppl 1) S25-S33, 2014.
Morton JP, Fell JM, Gonzalez JT, Hearris MA, Podlogar T, Pugh JN, Wallis GA. From metabolism to medals: contemporary perspectives and revisiting carbohydrate guidelines for fueling endurance athletes during exercise. J Nutr 156(5) 101442, 2026.
Plews DJ, Booth PD, Krieger T, Maunder E. Fuelled or fooled? Examining the evidence and mechanisms behind ultra-high carbohydrate intake in endurance athletes. Sports Med 56(10) 2367-2388, 2026.
Ravikanti S, Silang KG, Martyn HJ, Johnson KO, Louis JB, Bampouras TM, Owens DJ, Jones AM, Morton JP, Pugh JN. 13C-labelled glucose-fructose show greater exogenous and whole-body CHO oxidation and lower O2 cost of running at 120 versus 60 and 90 g/h in elite male marathoners. J Appl Physiol 139(6) 1581-1595, 2025.
Martyn HJ, Gonzalez JT, Stellingwerff T, Burke LM, Owens DJ, Pugh JN, Morton JP. Effects of 10, 90, 120 and 150 g/h CHO on substrate metabolism, exogenous oxidation and exercise capacity: implications for CHO personalization. Med Sci Sports Exerc 2026.
Norte BR, Slinn MM, Johnson KO, Mahon E, Shepherd SO, Strauss JA, Louis JB. Graded carbohydrate ingestion up to 120 g/h attenuates the reduction in critical power following 3 h of moderate-intensity exercise in a dose-dependent manner. Scand J Med Sci Sports 36(6) e70326, 2026.
Mazza OB, Ørtenblad N, Nielsen J, Lundby C, Gejl KD. Carbohydrate intake of 100 vs. 60 g/h during prolonged cycling improves durability without altering muscle glycogen utilization in male endurance athletes. Med Sci Sports Exerc 2026.
Smith JW, Pascoe DD, Passe DH, Ruby BC, Stewart LK, Baker LB, Zachwieja JJ. Curvilinear dose-response relationship of carbohydrate (0-120 g/h) and performance. Med Sci Sports Exerc 45(2) 336-341, 2013.
Triplett D, Doyle JA, Rupp JC, Benardot D. An isocaloric glucose-fructose beverage's effect on simulated 100-km cycling performance compared with a glucose-only beverage. Int J Sport Nutr Exerc Metab 20(2) 122-131, 2010.
Rowlands DS, Houltham SD. Multiple-transportable carbohydrate effect on long-distance triathlon performance. Med Sci Sports Exerc 49(8) 1734-1744, 2017.
Podlogar T, Bokal S, Cirnski S, Wallis GA. Increased exogenous but unaltered endogenous carbohydrate oxidation with combined fructose-maltodextrin ingested at 120 g/h versus 90 g/h at different ratios. Eur J Appl Physiol 122 2393-2401, 2022.
Podlogar T, Rowlands DS. Does 120 g/h carbohydrate ingestion really confer a metabolic advantage in elite marathoners? Methodological concerns and alternative interpretations. J Appl Physiol 140(6) 1802-1803, 2026.
Moseley L, Jentjens RL, Waring RH, Harris RM, Harding LK, Jeukendrup AE. Measurement of exogenous carbohydrate oxidation: a comparison of [U-14C]glucose and [U-13C]glucose tracers. Am J Physiol Endocrinol Metab 289(2) E206-E211, 2005.
Hearris MA, Pugh JN, Langan-Evans C, Mann SJ, Burke L, Stellingwerff T, Gonzalez JT, Morton JP. 13C-glucose-fructose labeling reveals comparable exogenous CHO oxidation during exercise when consuming 120 g/h in fluid, gel, jelly chew, or coingestion. J Appl Physiol 132(6) 1394-1406, 2022.
