Your marathon fueling strategy should be trained just like your pacing, endurance, and fitness.

This post was written by Coach Chris Knighton.

When preparing for a marathon, your physical training is only part of the equation. You also need to practice taking in carbohydrates and fluids while running.

A good marathon fueling plan can help you maintain your energy, support your race pace, and reduce the likelihood of falling apart late in the race. But the most important part of that plan is not what you write down before race day—it’s what you repeatedly practice during training.

Your long runs are your opportunity to train your fueling strategy so that by race day, eating and drinking while running feels familiar and routine.

Quick Answer: How Should You Fuel a Marathon?

For most marathoners, the goal is to begin fueling early and consistently rather than waiting until you feel depleted.

A practical starting point for many runners is:

• Take a gel approximately every 20–30 minutes
• Pay attention to the total grams of carbohydrate you consume each hour
• Drink according to your needs, thirst, weather conditions, and available aid stations
• Practice the entire strategy repeatedly during long runs before race day

If a gel contains approximately 25 grams of carbohydrate, taking one every 20–30 minutes provides roughly 50–75 grams of carbohydrate per hour. Your total carbohydrate intake may also include sports drink, chews, or other fuel.

There is no single perfect fueling plan for every runner. Your strategy should account for your race duration, pace, stomach tolerance, weather conditions, sweat rate, and the products you have successfully practiced with in training.

Fueling is one of the many details I help runners practice and personalize through my online marathon coaching so that their training, pacing, fueling, and race-day strategy work together.

When Should You Start Fueling During a Long Run?

Once your long runs begin extending beyond roughly 90 minutes, fueling should become an intentional part of the workout.

You are not just training your legs—you are also training your body to take in carbohydrates and fluids while running.

Don’t wait until you feel hungry, weak, or depleted before you begin fueling. One of the easiest mistakes to make during a marathon is falling behind on nutrition and then trying to make up for it later.

Instead, begin fueling relatively early and follow a consistent plan throughout the run.

How Many Carbs Per Hour Should Marathoners Take?

Rather than thinking only in terms of how many gels you take, learn how many grams of carbohydrate your fuel actually provides.

For prolonged endurance exercise, many runners will consume somewhere around 30–60 grams of carbohydrate per hour. During longer events such as the marathon, some well-practiced runners may benefit from higher intakes approaching 90 grams per hour if their stomach tolerates it.

For example, if your gel contains 25 grams of carbohydrate:

• 1 gel every 30 minutes = about 50 grams of carbohydrate per hour
• 1 gel every 25 minutes = about 60 grams of carbohydrate per hour
• 1 gel every 20 minutes = about 75 grams of carbohydrate per hour

If you are also drinking a carbohydrate-containing sports drink, count those carbohydrates toward your total as well.

You do not need to immediately jump to the highest possible carbohydrate intake. Start with an amount that you tolerate well and practice increasing it gradually when appropriate.

My Simple Starting Point for Long Runs

When athletes ask me how to begin practicing marathon fueling, I like to keep the initial strategy simple.

A good starting point is:

• Take a gel every 20–30 minutes
• Drink regularly based on thirst, conditions, and opportunities to take fluid
• Start practicing consistently during long runs rather than waiting until race day

I also recommend setting a recurring alert on your watch to remind you when it is time to fuel. One of the easiest mistakes to make is getting caught up in the run, forgetting to take nutrition, and then realizing later that you have fallen behind.

Taking a few sips of fluid at regular intervals or aid stations can also help establish a routine, but avoid forcing yourself to drink according to a rigid schedule if you do not need the fluid. Hydration needs vary considerably from runner to runner and from one weather condition to another.

What Gels Should You Use?

There is no single gel that works best for every runner.

Personally, I like Maurten Gel 100s (affiliate link – As an Amazon Associate I earn from qualifying purchases). They are more expensive than some other options, but I think about marathon fueling like putting gas in a car. If I am putting months of work into building a high-performance engine, I am willing to spend a little more on fuel that I trust and know works well for me.

That does not mean Maurten is the only good choice or that you need to use it. The most important thing is finding a product that:

• Provides a useful amount of carbohydrate
• Agrees with your stomach
• Is easy to carry and consume while running
• Has a taste and texture you can tolerate for several hours
• Can be used consistently during training and racing

Gels are also not mandatory. Some runners prefer chews, sports drink, or other easily consumed carbohydrate sources. What matters most is consistently getting enough carbohydrate from products you tolerate well.

Train Your Gut Before Race Day

Your stomach and intestines are part of marathon training too.

If you plan to consume 60–75 grams of carbohydrate per hour on race day, don’t make race day the first time you ask your body to process that much fuel while running.

Practice your fueling strategy during long runs. Start with an amount you tolerate well and gradually become comfortable taking carbohydrates while running for several hours.

If something repeatedly causes stomach problems, experiment during training with the amount, timing, concentration, or type of fuel rather than trying to solve the problem for the first time during your marathon.

By race day, taking your gels and fluids should feel routine rather than experimental.

What About Electrolytes and Sports Drinks?

Your hydration and electrolyte needs depend partly on how much you sweat, how much sodium you lose in your sweat, how long you are running, and the weather conditions.

There is nothing inherently wrong with drinking plain water. During longer runs, however, many runners find sports drinks useful because they can provide carbohydrates and electrolytes at the same time.

One of my favorite race-preparation strategies is to find out what sports drink your goal marathon will provide on the course and begin practicing with that exact product.

Buy some ahead of time and use it throughout your marathon build. By race day, you will already know how it tastes while running, how much you can comfortably drink, and how your stomach responds.

Do not assume that more fluid is always better. Drinking substantially more than your body needs can create its own problems. Use your training to learn what works for you across different temperatures and conditions.

Fueling and Hydration Work Together

Think of carbohydrates and fluids as two related but separate parts of your marathon plan.

• Gels, chews, and sports drinks can provide carbohydrate for energy.
• Water and sports drinks contribute fluid.
• Sports drinks may provide carbohydrate, fluid, and electrolytes at the same time.

During training, pay attention to approximately how many grams of carbohydrate you consume each hour as well as how much fluid feels comfortable in different conditions.

This is much more useful than blindly following someone else’s exact fueling schedule.

Should You Use Caffeine During a Marathon?

Caffeine can improve endurance performance for many runners, but it is not required and individual tolerance varies.

If you plan to use caffeinated gels, drinks, or other caffeine sources during your marathon, practice with them during training first.

I personally like beginning a marathon with non-caffeinated fuel and introducing caffeine later in the race. I have found that strategy helps me feel mentally sharp during the final portion of a marathon.

That is simply my personal preference rather than a rule everyone needs to follow. Some runners tolerate caffeine better than others, and taking too much can lead to unwanted effects such as stomach upset, jitters, or difficulty sleeping.

Nothing New on Race Day

This is one of the most important rules of marathon fueling.

Don’t try a new gel, breakfast, sports drink, caffeine strategy, or hydration plan for the first time during your goal marathon.

Use your long runs and race-specific workouts to experiment. Pay attention to what gives you energy, what is easy to consume, and what agrees with your stomach.

Once you find a strategy that works well, repeat it enough times that it becomes familiar.

Practice the Fuel Your Marathon Will Provide

Before your race, look at the marathon website and find out what will be available at aid stations.

If the race provides a particular sports drink and you plan to use it, buy that product and practice with it beforehand. If gels or other fuel will be available on the course, learn which products and flavors will be offered and decide whether you want to rely on them or carry your own.

The fewer surprises you have on race day, the better.

Turn Your Long Runs Into Race-Day Dress Rehearsals

As your marathon approaches, use some of your important long runs to rehearse as much of your race-day routine as possible.

Practice:

• The same breakfast you plan to eat before the marathon
• The same gels, chews, or other carbohydrate sources
• A similar fueling schedule
• The same sports drink when possible
• Your planned caffeine strategy
• How you will carry your nutrition
• Drinking while running

Race day should be the execution of a practiced plan—not a nutrition experiment.

Carb Loading Before the Marathon

Your marathon fueling strategy begins before the starting gun.

Increasing your carbohydrate intake in the days leading into your goal race can help maximize the carbohydrate stored in your muscles before you begin running.

Instead of trying to consume one enormous pasta dinner the night before the race, spread your carbohydrate intake throughout the days leading into the marathon and stick with familiar foods that you know sit well with your stomach.

Read my complete guide to carb loading before a marathon or half marathon.

Fueling Doesn’t Stop at the Finish Line

After a hard long run or marathon, begin refueling when you are able.

Your recovery nutrition should include carbohydrates to help replenish your energy stores, protein to support muscle repair, fluids, electrolytes when appropriate, and enough overall food to support recovery.

You do not need to panic if you cannot eat within exactly 30 minutes of finishing your run. The bigger priority is beginning the recovery process reasonably soon and continuing to eat and hydrate well throughout the rest of the day.

The Biggest Marathon Fueling Rule: Practice It

Don’t leave race-day fueling until race day.

Your long runs are your opportunity to train your fueling strategy just like you train your pacing, endurance, and fitness.

By the time you reach the starting line, you should already know:

• What you will eat before the race
• Which gels or other carbohydrate sources you will use
• Approximately how many grams of carbohydrate you will consume each hour
• How frequently you plan to fuel
• What you will drink
• Whether you will use the course sports drink
• Whether and when you will use caffeine
• How you will carry your fuel

Your nutrition plan should feel familiar and practiced long before race morning.

The exact strategy will be different for every runner. Use your training to develop a plan that provides enough fuel, agrees with your stomach, works with the conditions you expect to face, and gives you confidence heading into your marathon.