If your run lasts 30 or 45 minutes, you probably don’t need to carry gels, chews, or a sports drink with you. But once your runs begin extending beyond an hour-particularly when they are longer, harder, or part of marathon or endurance training-fueling becomes an important part of the workout.
And fueling isn’t only for race day. Learning how to take in carbohydrates and fluids while running is a skill that should be practiced during training, just like pacing, hill running, or running form.
Understanding why starts with understanding what your body is using for energy.
What Fuels Your Run?
Your body primarily relies on a combination of carbohydrates and fat to produce energy during endurance exercise.
Fat stores are abundant, even in relatively lean athletes. Carbohydrate stores, however, are limited. Carbohydrates are stored primarily as glycogen in your muscles and liver. During running, muscle glycogen can be broken down and used directly by the working muscles, while liver glycogen helps maintain blood glucose so that glucose remains available to both your muscles and your brain.
As exercise continues, those carbohydrate stores gradually decline. The faster or harder you run, the greater your reliance on carbohydrate tends to become. That is one reason carbohydrate availability becomes increasingly important during long runs, races, tempo sessions, and other sustained endurance workouts.
Current scientific consensus continues to support carbohydrate availability as an important component of endurance performance. Consuming carbohydrate during prolonged exercise can help maintain blood glucose and carbohydrate oxidation, allowing an athlete to sustain exercise intensity for longer.
Is 60 Minutes Really a Magic Number?
Not exactly. You don't reach 60 minutes and suddenly need food. Instead, think of 60 minutes as the point where fueling starts becoming increasingly relevant. For an easy 60-minute run after eating normally throughout the day, you may not need carbohydrates during the workout at all.
But during harder efforts lasting approximately an hour, even small amounts of carbohydrate may improve performance. Research has found benefits from carbohydrate exposure during higher-intensity exercise lasting around 45–75 minutes, even when the body's glycogen stores are not yet significantly depleted. Once you begin running for 75, 90, 120 minutes or longer, fueling becomes much more important.
The longer the run, the more important it becomes to provide carbohydrate from an outside source rather than relying exclusively on what you stored before you started.
How Much Carbohydrate Do Runners Need?
The amount depends primarily on how long you will be running, how hard you are running, what you ate beforehand, and how much carbohydrate your digestive system has been trained to tolerate.
A useful starting framework is:
Runs under about 60 minutes:
For most recreational runners, carbohydrate during the run is unnecessary. Water may be all you need depending on weather, sweat rate, and how well hydrated you were beforehand.
Runs around 60–75 minutes:
For easy running, you may still need very little. For harder workouts or races, small amounts of carbohydrate may be useful.
Runs approximately 1–2.5 hours:
Aim for roughly 30–60 grams of carbohydrate per hour.
Runs longer than approximately 2.5–3 hours:
Intakes may increase toward 60–90 grams of carbohydrate per hour, particularly for athletes trying to maximize endurance performance.
Research supports scaling carbohydrate intake with exercise duration rather than using one fueling recommendation for every athlete and every workout.
There is emerging research in highly trained endurance athletes investigating intakes around 120 grams per hour. However, this should not be considered a standard recommendation for the average runner. A recent review concluded that although higher intakes may have potential, evidence does not yet justify routinely recommending extremely high carbohydrate intakes to all endurance athletes.
For most runners, consistently tolerating 30–60 grams per hour is a very good place to begin.
Don't Wait Until You Feel Tired to Start Fueling
One of the most common mistakes I see with endurance athletes is waiting until they feel tired, hungry, shaky, or depleted before taking their first gel. By then, they are already trying to catch up. Instead, start fueling relatively early during a long run.
For example, during a two-hour run, you might take your first carbohydrate around 20–30 minutes and then continue taking smaller amounts regularly throughout the run.
Think of fueling as maintaining your energy supply rather than trying to rescue yourself after your energy has already dropped.
A simple strategy might look like:
25 grams of carbohydrate every 30 minutes = approximately 50 grams per hour
30 grams every 30 minutes = approximately 60 grams per hour
For a runner targeting higher carbohydrate intakes during very long races, smaller and more frequent doses are often easier to tolerate than taking a large amount at once.
What Counts as Fuel?
You don't necessarily need a special sports product.
Carbohydrate can come from:
Gels
Chews
Sports drinks
Bananas
Dates
Applesauce or fruit pouches
Pretzels
Energy bars
Other easily digested carbohydrate foods
Research comparing whole-food carbohydrate sources with sports nutrition products has generally found that both can work during endurance exercise when they provide appropriate amounts of carbohydrate. The important question isn't whether your fuel comes from a gel or a banana. It is whether you can comfortably digest it while running and whether it provides enough carbohydrate for your needs.
For many runners, gels, chews, or sports drinks are simply easier to carry and consume while moving.
Why Glucose and Fructose Matter on Longer Runs
Once carbohydrate intake starts increasing beyond approximately 60 grams per hour, the type of carbohydrate becomes more important.
Your intestines use different transport mechanisms to absorb glucose and fructose.
Using a combination of carbohydrate sources-often called multiple transportable carbohydrates- can allow the body to absorb and use more carbohydrate than relying heavily on glucose alone.
That is why many endurance gels and drinks designed for longer events contain combinations such as glucose or maltodextrin plus fructose. Research has demonstrated higher rates of carbohydrate oxidation when glucose and fructose are consumed together during prolonged exercise.
This becomes especially relevant for marathon runners, ultrarunners, cyclists, triathletes, and other endurance athletes attempting to consume 60–90 grams of carbohydrate per hour.
You Have to Train Your Gut Too
Your legs aren't the only thing you are training during a long run. You're also training your gastrointestinal system. Trying to consume 60–90 grams of carbohydrate per hour for the first time during a marathon is a recipe for stomach problems.
Instead, gradually practice fueling during training. If you currently take very little carbohydrate, you might begin with 25–30 grams per hour. Once that feels comfortable, gradually increase toward 40–50 grams.
Eventually, if your event requires it, you may practice 60 grams or more per hour. The goal is to find the highest amount that supports your performance while still feeling comfortable.
This is sometimes called gut training. It is particularly important for runners because running itself creates more gastrointestinal movement than activities such as cycling, making GI symptoms a common challenge.
Don't Forget Your Pre-Run Fuel
Fueling during the run is only one part of the equation. You also want to begin a long run with carbohydrate available.
Traditional sports nutrition recommendations suggest approximately 1–4 grams of carbohydrate per kilogram of body weight during the 1–4 hours before exercise, with the exact amount depending on the time available before the workout and the athlete's tolerance.
You don't need to turn that number into complicated math for every Saturday morning run. Practically, a pre-long-run meal might include:
Oatmeal with banana and honey
Toast or a bagel with fruit
Cereal with milk and banana
Rice with eggs
Toast with jam plus yogurt
A smoothie with fruit and oats
The closer you eat to your run, the smaller and easier to digest that meal should generally become.
Very high-fat, high-fiber, or unusually large meals immediately before running may increase gastrointestinal discomfort in some runners.
Hydration Is Part of Fueling Too
Long-run fueling isn't only about calories and carbohydrates. Fluid needs also increase as running duration increases, particularly in warm or humid conditions. There isn't one universal amount of water that every runner should drink.
Sweat rate can vary dramatically between athletes and can also change depending on temperature, humidity, intensity, clothing, body size, and heat acclimation.
For longer endurance sessions, approximately 400–800 mL of fluid per hour is often used as a broad planning range, but an individual runner may require more or less. The better approach is to learn your personal sweat rate under conditions similar to those in which you train and race.
And more fluid isn't always better. Overdrinking, especially large amounts of plain water, can contribute to dangerously low blood sodium levels called exercise-associated hyponatremia.
You should not finish a long endurance event weighing more than you did when you started because you drank excessive amounts of fluid.
What About Electrolytes?
Sweat contains water and electrolytes, with sodium being the electrolyte lost in the largest amount. How much sodium you lose varies considerably from one person to another. Some runners finish a workout with visible white salt marks on their clothes or skin. Others lose much less sodium.
Hot weather, high sweat rates, and longer training sessions increase the importance of thinking about both fluids and electrolytes.
For longer runs, using a sports drink or another source containing sodium can be practical, particularly for athletes who sweat heavily.
But just like fluid intake, electrolyte intake should be individualized rather than based on the assumption that every runner needs the same amount.
A Simple Two-Hour Long-Run Example
Imagine you're planning a two-hour long run.
You eat a carbohydrate-rich breakfast approximately two hours beforehand.
You begin your run well hydrated.
Around 25–30 minutes into your run, you take your first gel providing approximately 25 grams of carbohydrate.
You continue taking approximately 25 grams every 30 minutes.
Over the course of the run, that gives you approximately 50 grams of carbohydrate per hour.
You drink according to your needs throughout the run, increasing fluids appropriately if the weather is hot or your sweat rate is high.
That is a very different strategy from running for two hours with nothing and then wondering why the final 30 minutes feel dramatically harder.
Common Long-Run Fueling Mistakes
Waiting until you're exhausted to eat
Fuel early enough to prevent energy availability from falling significantly.
Taking one gel during a three-hour run
One gel may contain approximately 20–30 grams of carbohydrate. Spread across three hours, that is very little fuel.
Being afraid of carbohydrates
Carbohydrates are not something runners need to earn. During endurance exercise, they are a primary performance fuel.
Trying something new on race day
Your long runs are your fueling practice.
Increasing carbohydrate too quickly
Going from almost no fuel to 90 grams per hour overnight may cause GI problems. Build gradually.
Ignoring hydration
Carbohydrate, fluids, and electrolytes work together during prolonged endurance exercise.
Drinking excessive amounts of water
More is not automatically better. Hydration should match individual needs.
Fueling Is Part of Training
For runners preparing for a half marathon, marathon, ultra, long trail race, or simply progressively longer runs, nutrition should be considered part of the training plan-not something separate from it.
You train your cardiovascular system.
You train your muscles.
You train your pacing.
And you should train your fueling strategy.
The best fueling plan is not necessarily the one with the most carbohydrates or the most expensive sports products. It is the plan that gives you enough carbohydrate and fluid to support the demands of your run while remaining comfortable for your digestive system.
Start practicing during your long runs. Keep track of what you consume, when you consume it, how you feel, and what happens to your energy during the final portion of the run. Then adjust. Because finishing a long run strong isn't only about how fit your legs are.