TL;DR: A half marathon is long enough that fueling can matter, but short enough that you don't need to turn yourself into a mobile buffet. Start the race with full glycogen stores, eat a carbohydrate-rich pre-race meal, take in carbohydrates during the race based on your expected finish time, and drink according to your individual needs and conditions.

• Eat plenty of carbohydrates during the 24–48 hours before the race.

• Don't experiment with new foods the night before.

• Eat approximately 1–4 grams of carbohydrate per kilogram of body weight 1–4 hours before racing.

• Keep the pre-race meal relatively low in fat and fiber if you're prone to GI issues.

• For most runners racing longer than about 75–90 minutes, consuming carbohydrate during the race makes sense.

• Approximately 30–60 grams of carbohydrate per hour works well for many half marathon runners.

• Faster runners may need less total fuel simply because they're racing for less time.

• Slower runners may benefit from a more deliberate fueling schedule.

• Practice your race nutrition during training.

• Hydration should account for your sweat rate, weather, race duration, and aid-station availability.

• Don't force down excessive amounts of water just because you're afraid of dehydration.

Want the simple version? Use our Half Marathon Fueling Plan to build your pre-race meal, carbohydrate, hydration, and race-day fueling strategy before you get to the starting line.

You've probably spent months preparing your legs for a half marathon.

Long runs.

Tempo runs.

Intervals.

Easy miles.

Maybe some strength training if I've managed to convince you.

Then race morning arrives and suddenly nutrition becomes:

"I ate half a banana and found an old gel in my car."

We can do better.

A half marathon sits in an interesting nutritional middle ground.

It's not a marathon.

Most runners aren't going to completely empty their carbohydrate stores during 13.1 miles.

But it's also not a 5K.

Depending on your pace, you might be racing for anywhere from a little over an hour to three hours or more.

At that point, nutrition can absolutely affect performance.

Here's how I'd approach it.

Why Carbohydrates Matter During a Half Marathon

Your muscles use a combination of carbohydrate and fat to produce energy during endurance exercise.

As intensity increases, carbohydrate becomes increasingly important.

That's useful because carbohydrate can produce energy relatively quickly.

The downside is that your body's carbohydrate stores are limited.

Carbohydrate is primarily stored as glycogen in your muscles and liver.

You begin a race with a finite amount.

Fortunately, you can increase carbohydrate availability before the race and consume additional carbohydrate while running.

That's the basic goal of half marathon fueling.

Start with a full tank.

Then top it off while you're running.

Do You Need to Carb Load for a Half Marathon?

This depends partly on how long you expect to race.

Traditional carbohydrate-loading protocols are particularly useful before prolonged endurance events where glycogen depletion can meaningfully limit performance.

A half marathon is right on the edge for many runners.

Someone racing for 70 minutes has a very different nutritional challenge than someone racing for 2 hours and 45 minutes.

For most runners, I wouldn't make half marathon carb loading unnecessarily complicated.

Instead, increase carbohydrate intake during the day or two before the race while slightly reducing training volume.

Think:

Rice.

Pasta.

Potatoes.

Bread.

Oatmeal.

Fruit.

Cereal.

Bagels.

Sports drinks.

Your plate should gradually become more carbohydrate-focused as race day approaches.

You don't need to eat six pounds of spaghetti Saturday night.

What Should You Eat the Day Before a Half Marathon?

The goal is boring.

And boring is good.

Eat familiar foods that are high in carbohydrate and relatively easy to digest.

The day before your race is not the time to celebrate your fitness by trying a restaurant's five-alarm ghost pepper burrito.

Good carbohydrate options include:

• Rice

• Pasta

• Bread

• Bagels

• Potatoes

• Oatmeal

• Cereal

• Pancakes

• Fruit

• Pretzels

• Low-fiber snack foods

• Sports drinks or juice when additional carbohydrate is useful

You can still eat protein.

You can still eat some fat.

We're simply shifting the balance toward carbohydrates.

Should You Avoid Fiber Before a Half Marathon?

You don't necessarily need to eliminate fiber.

But runners who experience GI problems may benefit from reducing fiber during the final day before racing.

Fiber is normally great.

Race morning is one of the rare occasions where I'd rather not test exactly how efficient your digestive system can be.

If you're prone to urgent bathroom stops during runs, consider reducing:

Large salads.

Beans.

Huge servings of vegetables.

High-fiber cereals.

Large quantities of whole grains.

Again, practice this before race day.

Your digestive system gets a vote.

What Should You Eat the Morning of a Half Marathon?

General sports-nutrition recommendations suggest consuming approximately 1–4 grams of carbohydrate per kilogram of body weight during the 1–4 hours before exercise, with the amount generally increasing when there's more time available for digestion.

That's a wide range because people are different.

Race timing is different.

Body size is different.

GI tolerance is very different.

A runner eating four hours before the race can comfortably consume considerably more food than someone eating 60 minutes before the gun.

Example Pre-Race Breakfast

For a 160-pound runner, which is approximately 73 kilograms, a moderate pre-race carbohydrate target might be around:

100–150 grams of carbohydrate approximately 2–3 hours before the race.

That could look something like:

Bagel with honey: 60–70 g carbohydrate

Banana: 25–30 g

Sports drink: 25–30 g

Total: roughly 110–130 g carbohydrate

You could also use:

Oatmeal.

Toast.

Pancakes.

Rice.

Cereal.

A PB&J.

Whatever works for you.

The best pre-race breakfast isn't the one somebody on Instagram says is optimal.

It's the one that gives you carbohydrates without making your stomach file a formal complaint at mile four.

What About Protein Before the Race?

A little protein is fine.

Something like 15–25 grams works well for many runners.

You don't need a massive serving.

The priority before a half marathon is carbohydrate availability and comfortable digestion.

A little Greek yogurt, eggs, milk, or protein in your oatmeal is fine if you're accustomed to it.

Keep the meal familiar.

What About Fat?

Fat digests relatively slowly.

That isn't inherently bad.

But a large high-fat meal shortly before running can cause problems for some people.

I'd probably skip the giant breakfast platter with bacon, sausage, hash browns, cheese, avocado, and whatever else we can find in the refrigerator.

Save that for after the race.

Should You Eat Right Before the Start?

You can.

A small carbohydrate feeding approximately 10–20 minutes before the start can be useful, particularly if several hours have passed since breakfast.

For example:

A gel.

A few chews.

Half a banana.

Sports drink.

Something providing roughly 20–30 grams of carbohydrate works well for many runners.

Again, practice it first.

Notice a theme?

How Much Carbohydrate Should You Eat During a Half Marathon?

This is where finish time matters.

For prolonged exercise, established recommendations commonly fall around 30–60 grams of carbohydrate per hour.

Higher carbohydrate intakes can be useful during longer endurance events, particularly beyond roughly 2½ hours.

For a half marathon, I'd make the plan based on expected finishing time.

Under 75 Minutes

You're moving.

Fast.

Your race may be short enough that large amounts of carbohydrate aren't necessary.

Starting with good carbohydrate availability is the priority.

A small amount of carbohydrate during the race or even carbohydrate mouth rinsing may provide benefit during high-intensity endurance exercise.

You probably don't need four gels.

75–90 Minutes

I'd consider approximately:

20–40 grams of carbohydrate per hour.

For many runners this could mean one gel around 30–40 minutes into the race.

Potentially another small carbohydrate feeding later depending on preference and expected finish time.

90 Minutes to 2 Hours

Now fueling becomes more relevant.

A good target is approximately:

30–60 grams of carbohydrate per hour.

For example, if your gels contain 25 grams of carbohydrate:

20 minutes: Gel

45–50 minutes: Gel

70–80 minutes: Gel

Potentially another later depending on finish time and tolerance.

You don't need to follow those exact minutes.

The point is to start fueling before you're tired.

2–2½ Hours

I'd become more deliberate.

Aim for roughly:

40–60 grams of carbohydrate per hour.

You might consume carbohydrate every 20–30 minutes using:

Gels.

Chews.

Sports drink.

Or some combination.

This is also where practicing your fueling becomes increasingly important.

Longer Than 2½ Hours

Runners spending more than 2½ hours on the course can potentially benefit from carbohydrate intakes approaching the higher end of endurance recommendations.

That might mean:

60–90 grams per hour, depending on tolerance and training.

However, don't jump from eating nothing during training to trying 90 grams per hour on race day.

Your gut will probably have some thoughts about that.

What Type of Carbohydrate Is Best During a Half Marathon?

Convenience matters.

You're running.

This isn't the ideal time for a baked potato.

Most runners use:

Energy gels

Easy to carry and typically provide around 20–30 grams of carbohydrate.

Chews

Easy to divide into smaller doses.

Sports drinks

Provide carbohydrate and fluid simultaneously.

Liquid carbohydrate products

Useful for runners who prefer drinking calories.

At higher carbohydrate intakes, products containing multiple carbohydrate sources such as glucose or maltodextrin combined with fructose can increase the amount of exogenous carbohydrate that can be oxidized.

For most half marathon runners targeting 30–60 grams per hour, almost any well-tolerated sports nutrition product can work.

Tolerance matters more than marketing.

When Should You Take Your First Gel?

Earlier than most runners think.

Don't wait until you feel tired.

Once you feel like you're running out of fuel, you're trying to solve a problem that already exists.

For a runner planning to fuel during a half marathon, I'd generally start somewhere around:

20–30 minutes into the race.

Then continue at regular intervals.

For example:

0:25

0:50

1:15

1:40

Obviously adjust based on your target carbohydrate intake and the carbohydrate content of the product you're using.

The schedule should be boring.

That's good.

You don't want to be doing nutritional calculus at mile 10.

Should You Take Gels With Water?

Usually, yes.

Many gels are concentrated carbohydrate.

A little water can improve comfort and help wash them down.

If you're using a carbohydrate drink instead, account for the carbohydrate in that drink when calculating your hourly intake.

This is an easy mistake.

Someone says they're eating 60 grams per hour from gels.

They're also drinking 40 grams per hour from sports drink.

Congratulations.

You're now at 100.

Math still works during races.

How Much Should You Drink During a Half Marathon?

There isn't one correct number.

Fluid needs vary enormously depending on:

• Body size

• Sweat rate

• Temperature

• Humidity

• Pace

• Acclimation

• Clothing

• Individual physiology

That's why blanket recommendations like "drink eight ounces every 15 minutes" aren't particularly useful.

You want to avoid both significant dehydration and excessive fluid consumption.

Fluid-replacement guidance emphasizes individualizing intake based on sweat rate and environmental conditions rather than blindly consuming as much fluid as possible.

Overdrinking can also contribute to exercise-associated hyponatremia.

More water isn't always better.

How Do You Calculate Your Sweat Rate?

You can estimate sweat rate during training.

1. Weigh yourself before a run.

2. Track how much fluid you drink.

3. Run for approximately one hour under conditions similar to race day.

4. Weigh yourself afterward.

5. Account for fluid consumed and urine produced.

For example:

Pre-run weight: 160 lb

Post-run weight: 159 lb

Fluid consumed: 16 oz

You've lost approximately one pound of body weight plus the 16 ounces you drank.

One pound of water is roughly 16 fluid ounces.

Estimated sweat loss:

~32 oz per hour

That doesn't automatically mean you need to drink 32 ounces every hour.

It gives you useful information for developing a plan.

We actually have a free Sweat Rate Calculator on the Simply Good Supplements site that makes this calculation considerably easier.

Do You Need Electrolytes During a Half Marathon?

Maybe.

Sodium is the electrolyte runners usually care about most because it's the primary electrolyte lost in sweat.

But sweat sodium concentration varies substantially between athletes.

So does sweat rate.

A runner losing a liter of sweat per hour with a high sodium concentration is losing considerably more sodium than someone sweating half as much with a lower sodium concentration.

Weather matters too.

For a cool 75-minute half marathon, electrolyte replacement probably isn't going to be a major nutritional challenge.

For a 2½-hour race in hot conditions?

Different situation.

This is why individualized hydration and electrolyte strategies make more sense than declaring that every runner needs exactly 1,000 mg of sodium per hour.

Does Sodium Prevent Muscle Cramps?

Not reliably.

This is another endurance-sports myth that refuses to leave.

Exercise-associated muscle cramps are complicated.

Fatigue and neuromuscular factors appear to play important roles.

Some athletes may experience problems associated with substantial sodium and fluid losses, but swallowing huge amounts of salt isn't a guaranteed cramp-prevention strategy.

Don't use sodium as an insurance policy against every possible race problem.

Should You Drink at Every Aid Station?

Not necessarily.

Aid stations are opportunities.

They're not mandatory drinking checkpoints.

Drink according to your plan, thirst, environmental conditions, and sweat rate.

If you're thirsty, drink.

If it's hot and you're sweating heavily, you'll probably drink more.

If it's 40°F and you're finishing in 80 minutes, you'll probably drink considerably less.

That's normal.

What About Caffeine?

Caffeine can improve endurance performance.

For many runners, something around 1.5–3 mg/kg is enough to provide a useful dose without creating unnecessary side effects.

Traditional sports-nutrition recommendations often discuss higher doses, but you don't need to see God at mile six for caffeine to work.

If you already drink coffee, your normal pre-race caffeine intake may be plenty.

You can also use caffeinated gels later in the race.

Just calculate your total intake.

Don't accidentally consume:

Coffee.

Pre-workout.

Three caffeinated gels.

Energy drink.

And then wonder why your heart is attempting to qualify for Boston separately from the rest of your body.

Practice caffeine use during training.

Should You Carb Load the Night Before?

Carbohydrate loading isn't one giant dinner.

That's probably the most important thing to understand.

Muscle glycogen accumulation occurs over time.

If you're intentionally increasing carbohydrate intake, spread it throughout the day.

Breakfast.

Lunch.

Snacks.

Dinner.

Fluids if necessary.

Trying to consume the entire carbohydrate load at Olive Garden at 7 p.m. is mostly a good strategy for going to bed uncomfortable.

A Sample Half Marathon Nutrition Plan

Let's use a runner expecting to finish around 1:45.

Day Before

Eat carbohydrate-rich meals throughout the day.

Keep foods familiar.

Reduce fiber somewhat if GI problems are common.

Hydrate normally.

Don't force gallons of water.

2–3 Hours Before Race

Approximately:

100–150 g carbohydrate

15–25 g protein

Moderate fluid intake.

For example:

Bagel with honey.

Banana.

Greek yogurt.

Sports drink.

15 Minutes Before

20–25 g carbohydrate

One gel or equivalent.

Small amount of water.

During Race

Target:

40–60 g carbohydrate per hour

Example:

25 minutes: 25 g gel

50 minutes: 25 g gel

75 minutes: 25 g gel

Potential additional carbohydrate from sports drink.

Drink according to conditions and individual needs.

That's it.

It doesn't need to be complicated.

Practice Your Race Nutrition

This may be the most important piece of advice in the article.

Race day should not be a nutrition experiment.

Practice your:

Breakfast.

Gel brand.

Gel flavor.

Carbohydrate intake.

Caffeine.

Fluid intake.

Electrolytes.

Timing.

Use long runs and race-specific workouts.

Your gastrointestinal tract can adapt to carbohydrate intake during exercise, particularly when you practice consuming the amounts you intend to use during competition.

The first time you attempt 60 grams of carbohydrate per hour shouldn't be while wearing a race bib.

Common Half Marathon Fueling Mistakes

Not Eating Enough Before the Race

Running 13.1 miles after eating 180 calories because you're worried about stomach problems isn't a great solution.

Practice eating before running.

Waiting Until You're Tired to Fuel

Fuel early.

Don't wait for your body to send an emergency notification.

Eating Too Much

A half marathon isn't an ultramarathon.

You don't need a sandwich, potato chips, gummy bears, and a quesadilla at mile eight.

Drinking Too Much Water

More isn't automatically better.

Excessive fluid intake can be dangerous.

Trying New Products on Race Day

The expo gave you a free gel you've never tried?

Wonderful.

Eat it Tuesday.

Ignoring the Weather

A fueling plan for 45°F isn't necessarily a hydration plan for 80°F.

Adjust accordingly.

Copying Someone Else's Plan

Your 120-pound running partner and your 200-pound training partner may have very different needs.

Individualize.

What Should You Eat After a Half Marathon?

Your immediate nutritional priorities are:

Carbohydrate

Protein

Fluid

Sodium and other nutrients through food and fluids

If you aren't training again soon, you don't need to obsess about a 30-minute recovery window.

Eat a good meal.

If another hard training session or competition is coming quickly, aggressive carbohydrate replacement becomes more important.

A practical post-race meal might include:

Rice or potatoes.

Chicken or beef.

Vegetables.

Fruit.

Fluids.

Or pizza.

I'm not going to pretend pizza suddenly stops containing carbohydrate, protein, sodium, and calories because it tastes good.

You've just raced 13.1 miles.

Enjoy lunch.

The Best Half Marathon Fueling Plan Is the One You've Practiced

There isn't one universal perfect half marathon nutrition plan.

Your strategy depends on:

Your pace.

Your expected finishing time.

Your sweat rate.

The weather.

Your gastrointestinal tolerance.

The products available on the course.

Your caffeine habits.

Your pre-race diet.

The runner finishing in 1:15 and the runner finishing in 2:45 are participating in the same event.

They aren't dealing with the same nutritional problem.

Build your plan around your race.

Then practice it until it's boring.

Boring is exactly what you want from race-day nutrition.

Want Your Half Marathon Fueling Plan Built Out?

You don't need to remember every number in this article while you're standing at the grocery store three days before your race.

Use our Half Marathon Fueling Plan to organize what to eat before your race, how much carbohydrate to consume, when to fuel during the race, and how to approach hydration.

Get the Half Marathon Fueling Plan →

You can also browse all of our free training programs and workout plans for running, strength, endurance, hybrid training, race nutrition, and more.

Train the plan.

Practice the fuel.

Then race.

Frequently Asked Questions About Half Marathon Nutrition

What should I eat before a half marathon?

Eat a carbohydrate-rich meal using familiar, easily digested foods. Depending on timing and tolerance, approximately 1–4 grams of carbohydrate per kilogram of body weight during the 1–4 hours before exercise is a commonly recommended range.

How many carbs should I eat during a half marathon?

For most runners racing longer than roughly 75–90 minutes, approximately 30–60 grams of carbohydrate per hour is a useful starting range. Runners taking longer than 2½ hours may benefit from higher intakes if they've practiced them.

How many gels do I need for a half marathon?

It depends on finish time and the carbohydrate content of the gel. A runner targeting 40–60 grams of carbohydrate per hour using gels containing 25 grams each might consume roughly one gel every 25–35 minutes.

When should I take my first gel during a half marathon?

Around 20–30 minutes into the race works well for many runners who plan to fuel. Starting early is generally better than waiting until fatigue appears.

Should I take a gel before the race?

A gel providing approximately 20–30 grams of carbohydrate 10–20 minutes before the start can be useful, particularly when several hours have passed since your pre-race meal.

Should I drink water with energy gels?

Usually. Many gels are highly concentrated, and consuming some water with them can improve comfort. Follow the product instructions and practice the strategy during training.

Should I carb load for a half marathon?

Increasing carbohydrate intake during the day or two before racing can help maximize carbohydrate availability, particularly for runners who will be racing for a longer period. A huge pasta dinner the night before isn't necessary.

What should I eat the night before a half marathon?

Choose a familiar meal containing plenty of carbohydrate, moderate protein, and an amount of fat and fiber you tolerate well. Rice, pasta, potatoes, bread, lean protein, and familiar foods generally work well.

How much should I drink during a half marathon?

Fluid needs vary according to sweat rate, temperature, humidity, body size, pace, and race duration. Avoid both significant dehydration and excessive drinking. Practicing your hydration strategy during training is more useful than following a universal fluid number.

Do I need electrolytes during a half marathon?

Not every runner needs the same electrolyte strategy. Sodium needs depend largely on sweat rate, sweat sodium concentration, race duration, environmental conditions, and fluid intake.

Should I use caffeine during a half marathon?

Caffeine can improve endurance performance. Lower doses can be effective, and many runners can obtain enough through coffee, a pre-race product, or caffeinated gels. Test your caffeine strategy before race day.

What should I eat after a half marathon?

Eat a meal containing carbohydrate and high-quality protein and replace fluids according to your losses. If you don't have another demanding workout or competition soon, there's no need to panic about eating within an exact 30-minute window.

About the Author

Matt Mosman, MS, CISSN, CSCS

Matt Mosman is the founder and Chief Science Officer of Simply Good Supplements. He holds a master's degree and is a Certified Sports Nutritionist through the International Society of Sports Nutrition (CISSN) and a Certified Strength and Conditioning Specialist (CSCS).

He's also an endurance runner, which means this isn't entirely an academic discussion.

Race nutrition should make running easier.

It shouldn't become another event you're simultaneously competing in.

Start with carbohydrates.

Figure out your fluid needs.

Use electrolytes when they're appropriate.

Practice everything.

Then stop thinking about nutrition and race.

References

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6. McDermott BP, Anderson SA, Armstrong LE, et al. National Athletic Trainers' Association Position Statement: Fluid Replacement for the Physically Active. Journal of Athletic Training. 2017;52(9):877–895.

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8. Jeukendrup AE. The Use of Carbohydrates During Exercise as an Ergogenic Aid. Sports Medicine. 2014;44(Suppl 1)–S33.