There is a specific kind of silence that happens around the 30 km mark of a marathon, or an hour and a half into a long ride, when your legs stop answering the way they did at the start. Most athletes assume it is a fitness problem. Often, it is a math problem. One possible culprit is carbohydrate availability: your muscles may be using carbohydrate faster than you’re replacing it.

Sports science has quietly rewritten its answer to this problem over the past twenty years. The carbohydrate targets most runners and cyclists were taught, a gel here or there, maybe 30 grams an hour, are now considered conservative by current research standards. Research on multiple transportable carbohydrates has substantially expanded our understanding of how much carbohydrate athletes can effectively use during prolonged exercise.

This guide breaks down what the current research actually says about carbs per hour for endurance exercise, how that translates to real-world fuelling with energy gels, and how to build a strategy that keeps you moving without wrecking your stomach.

How Your Carb Needs Change With Exercise Duration

The answer depends almost entirely on how long you are exercising and how hard you are pushing. A 2022 survey published in Frontiers in Nutrition summarized the contemporary guidance from the American College of Sports Medicine this way: athletes doing high intensity efforts lasting 45 to 75 minutes benefit from small amounts of carbohydrate or even just a mouth rinse, while those exercising for 1 to 2.5 hours should aim for roughly 30 to 60 grams of carbohydrate per hour, and athletes going beyond 2.5 to 3 hours can target up to 90 grams per hour.

That said, "up to 90 grams" is no longer the ceiling it once was. Research summarized in the journal Sports Medicine traced how the field moved from believing 22 grams of carbohydrate per hour was the minimum threshold for a performance benefit, to recognizing that trained athletes using the right carbohydrate blends can oxidize considerably more. 

For most recreational endurance athletes, a practical starting range looks like this:

• Under 60 minutes: little to no carbohydrate is usually necessary if you started well fueled

• 1 to 2.5 hours: 30 to 60 grams of carbohydrate per hour

• Beyond 2.5 hours: 60 to 90 grams per hour, with trained athletes going higher

Higher carbohydrate intakes require practice. Gradually training your gut can help you find an intake that supports performance while remaining comfortable and well tolerated.

Why Carbohydrate Needs Vary Between Endurance Athletes

There is no single carbohydrate target that works for every endurance athlete. How much carbohydrate an athlete can effectively consume during exercise depends on factors including exercise duration and intensity, carbohydrate dose and composition, individual gastrointestinal tolerance, and how well the gut has been trained to handle carbohydrate during exercise.

Research in trained endurance and ultra-endurance runners illustrates this variability. A study examining carbohydrate intakes of 76 to 90 grams per hour found considerable differences in gastrointestinal responses between athletes, with higher carbohydrate intake associated with greater gastrointestinal symptom severity and feeding intolerance.

More recent research shows that some highly trained athletes may be able to use considerably higher amounts. In elite male marathoners, consuming 120 grams of carbohydrate per hour from glucose and fructose resulted in greater exogenous carbohydrate oxidation than consuming 60 or 90 grams per hour. However, gastrointestinal symptoms were common across all intake levels and some symptoms were greatest at 120 grams per hour, highlighting the importance of gradually training the gut rather than simply aiming for the highest possible intake.

The takeaway for runners and cyclists is that more carbohydrate is not automatically better. The goal is to find an intake that provides enough fuel for the duration and intensity of the activity while remaining comfortable and well tolerated.

Why the Glucose-to-Fructose Ratio Matters

For years, sports nutrition assumed the gut could only absorb about 60 grams of glucose per hour, because glucose relies on a single intestinal transporter, SGLT1, which becomes saturated at that rate. Once researchers started pairing glucose with fructose, which uses a separate transporter called GLUT5, everything changed.

Research in trained cyclists found that combining glucose and fructose at high intake rates increased peak exogenous carbohydrate oxidation to approximately 1.75 grams per minute, compared with 1.06 grams per minute with glucose alone. This demonstrated that using multiple carbohydrate sources could support substantially higher oxidation rates than glucose alone.

More recent research has explored whether carbohydrate ratios closer to 1:1 may be useful at higher intake rates. A 2022 study in highly trained cyclists compared 120 grams per hour at a 0.8:1 fructose-to-glucose-based carbohydrate ratio with 90 grams per hour at the more traditional 1:2 ratio. The 0.8:1 fructose-to-glucose ratio studied here is equivalent to the 1:0.8 glucose-to-fructose ratio used in Herbaland's Energy Gel. The 120-gram condition resulted in significantly greater exogenous carbohydrate oxidation, without significantly greater gastrointestinal discomfort. However, because both the carbohydrate dose and ratio differed between conditions, the study cannot determine whether the higher oxidation was due to the ratio, the greater carbohydrate intake, or both.

These findings add to research suggesting that multiple transportable carbohydrates and the balance between glucose and fructose can influence how effectively carbohydrates are used during prolonged exercise. Individual tolerance still varies considerably, making gradual gut training important when increasing carbohydrate intake.

How often should you take energy gels?

Once you know your target carbs per hour, the next question is timing. Rather than waiting until you feel depleted, carbohydrate should generally be consumed regularly throughout prolonged endurance exercise, with the amount and frequency determined by your hourly carbohydrate target.

Research suggests that how frequently carbohydrates are consumed may also matter. In a study of trained cyclists, participants consumed an energy gel 15 minutes before exercise and then either every 30 minutes, every 45 minutes, or not at all during two hours of cycling. Both gel strategies improved subsequent time-trial performance compared with consuming no gels during exercise, while the 30-minute strategy produced the greatest distance, suggesting that more frequent carbohydrate intake may provide additional benefits in some circumstances.

As a general framework:

• Work out your hourly carbohydrate target based on exercise duration and intensity

• Divide that number by the carbohydrate content of your gel to determine how many you need per hour

• Space your intake evenly throughout the hour based on that target and your individual tolerance

• Practise your fueling strategy during training before using it on race day

How to use energy gels for running and cycling without gut distress

How to fuel during endurance exercise comes down to several factors working together, including carbohydrate amount and composition, fluid intake, exercise intensity, and individual gastrointestinal tolerance. At higher carbohydrate intakes, combining glucose and fructose allows carbohydrate to be transported through different intestinal pathways, helping support higher rates of carbohydrate oxidation than glucose alone. However, tolerance varies between athletes, which is why higher carbohydrate targets should be practised gradually during training.

Where Herbaland's Energy Gel fits into your fueling strategy

If you are searching for the best energy gels for running or the right energy gel for cycling, the formulation matters just as much as the flavour on the label. Herbaland's Energy Gel delivers 24 grams of carbohydrates and 100 calories per pouch, with a 1:0.8 glucose-to-fructose ratio designed to provide an effective source of fuel during endurance exercise. Its caffeine-free formula has a smooth, easy-to-consume texture, comes in two flavours (lemon lime and unflavoured), and requires no water, making it easy to fuel on the move.

For runners, cyclists, and endurance athletes, the 24 grams of carbohydrate per pouch also makes it simple to build a fueling strategy around your hourly target. Two gels provide 48 grams of carbohydrate, fitting within the 30 to 60 gram per hour range commonly recommended for endurance exercise lasting 1 to 2.5 hours. For longer events or higher carbohydrate targets, intake can be adjusted and practised during training based on individual tolerance. Simply tear, squeeze, and keep moving.

Because the formula is caffeine-free, athletes can manage carbohydrate and caffeine intake separately, making it easier to incorporate caffeinated products elsewhere in a race plan without getting caffeine from every gel.

Frequently asked questions

How many carbs per hour should I consume during endurance exercise?
Aim for 30 to 60 grams of carbohydrate per hour for exercise lasting 1 to 2.5 hours, and up to 90 grams per hour for longer endurance exercise. Higher intakes may work for some gut-trained athletes.

How many energy gels should I take per hour?
Divide your hourly carbohydrate target by the carbs in each gel. Herbaland Energy Gel provides 24 grams per pouch, so two gels provide 48 grams of carbohydrate per hour.

How often should you take energy gels during running or cycling?
Space gels evenly based on your hourly carbohydrate target. For example, two Herbaland Energy Gels per hour can be taken about 30 minutes apart. Practise your strategy during training to find what works best for you.

How should I use energy gels for running?
Consume gels regularly during longer runs rather than waiting until you feel depleted. Base your timing on your hourly carbohydrate target and practise your race-day fueling strategy during training.

What is the best way to fuel during endurance exercise?
Match carbohydrate intake to exercise duration and intensity, consume it regularly, and gradually train your gut to tolerate your target intake. Glucose-fructose blends can support higher carbohydrate oxidation rates at higher intakes.

Why do energy gels use glucose and fructose together?

Glucose and fructose use different intestinal transporters, allowing the body to absorb and oxidize more ingested carbohydrate during prolonged exercise than glucose alone, particularly at high carbohydrate intakes.

Are caffeine-free energy gels good for running and cycling?
Yes. Caffeine-free energy gels provide carbohydrates without added caffeine, allowing athletes to manage their carbohydrate and caffeine intake separately during training and racing.