What to Eat While Running

Last updated: 31 Mar 2024

Deciding what to eat while running is only needed when you are going to run for more than 90 minutes.

Eating while running is a new experience for most people, it can be daunting at first – but it get’s easier with practice.

You don’t need to eat on shorter runs, just make sure you understand what to eat before running.

When doing a longer run:

Pre-fuel by eating fist-sized portions of complex carbs 4 to 6 times a day in the 24 hours before your run.
Start eating simple carbs (sweet stuff) 60 minutes into your run, then every 45 minutes.

Once a week, on very slow runs you can practice training low by not eating anything during the run, training your body to fuel from body fat.

Summary

Endurance run
Training low run
When to eat while running
How much to drink while running
What happens if you don’t eat while running?
What NOT to eat while running
How food is used as fuel
Calories stored in glycogen
Diet considerations
Common mistakes when eating while running
FAQs

What to eat while running more than 90 minutes

How do I find the HR%?

Heart rate is the number of beats per minute that your heart takes.

The most practical way to measure your heart rate during a run is to use a running watch such as Garmin Forerunner 45 or Forerunner 255.

Your maximum heart rate is the upper limit that your heart can handle during exercise. ^[1]It won’t physically beat any faster than your maximum rate, which gradually decreases with age.

Your maximum heart rate can be estimated by using this formula: ^[2]

Maximum Heart Rate = 206.9 – (0.67 x age)

The table below uses this formula to estimate the maximum heart rate for various ages. For each age, it shows the values at the different heart rate zones.

If you plan to run at a moderate intensity for longer than 90 minutes, you’ll need to take along a snack or two to prevent hitting the wall.

Age	< 50% (Low Intensity)	< 60% Training Low	50% to 70% Moderate Intensity	> 70% High Intensity
20	< 90	< 110	90 to 131	> 131
25	< 86	< 107	86 to 128	> 128
30	< 83	< 104	83 to 124	> 124
35	< 80	< 100	80 to 121	> 121
40	< 76	< 97	76 to 118	> 118
45	< 73	< 93	73 to 114	> 114
50	< 69	< 90	69 to 111	> 111
55	< 66	< 87	66 to 107	> 107
60	< 63	< 83	63 to 104	> 104
65	< 59	< 80	59 to 101	> 101
70	< 56	< 77	56 to 97	> 97
75	< 53	< 73	53 to 94	> 94

Endurance run (>60% HR)

An endurance run is more than 90 mins, at more than 60% maximum heart rate.

Attempting an endurance run without enough carbohydrates can lead to hitting the wall also known as bonking.

Depending on the intensity, you’ll need about 30-90g of carb per hour – Start training with 30g of carbs per hour and only increase if you find you need more.

Start eating 60 minutes into your run, then every 45 minutes – Don’t wait until you run out of fuel, by then it will be too late.

Even though the calories burned running a marathon or an endurance run are high, choosing what to eat during your run is not just about fuel requirements… it’s also about overcoming the mental challenge, so choose something you’re going to enjoy.

Choose snacks that are easily and quickly absorbed into the bloodstream (high GI).

Be aware of options that may be choking hazards as you’ll be eating while running.

Eating or drinking while running might feel strange at first so it’s vital to practice it. Your gut needs to be trained to get used to digesting while running.

Use long runs as an opportunity to figure out what works for you and to practice a race day strategy. It’s important to work out what works for you as what to eat while running is very much an individual thing. ^[3]

If you’re planning to run a half marathon and want to know how many calories you can burn, read Calories burned running a half marathon.

Snacks to eat while running

Energy Bar

4 to 5 Jelly Babies

Peanut M & M's

Dates

Choose fast-release carbs that you enjoy eating such as:

Energy gels in your favorite flavors
Energy bars
Jelly Babies
Peanut M & M’s
Dates
Raisins
Sports drinks

If you enjoy more natural options, raisins are as effective as sports gels. ^[4]

Don’t forget to practice the best way to carry your snacks. While your favorite snack might look tempting initially, once it’s spent an hour in a sweaty shorts pocket, you might change your mind.

It’s also good to have a quick fast-release recovery drink available at the end of your run. For more on this read What to eat after running.

Training low run (<60% HR)

Training low is running for more than 90 minutes with a heart rate less than 60%.

The purpose is to teach your body to fuel your runs from fat.

You should not eat before or during a training low run.[5]

Training low should only be done once a week and you must not run any faster than 60% maximum heart rate.

Studies have shown that training low helps you become fat-adapted by improving your body’s ability to convert fat into fuel.^[5]

Only do one of these runs a week and keep your heart rate below 60% max.

Exceeding either of these can lead to a depressed immune system.^[6]

When to eat while running

It’s key you eat while running, before you need the fuel, so you have time to release the energy.

You can use either time or distance to know when it’s time to eat – choose whichever you find easier to track.

The best way is to experiment during longer runs and work out which approach is easiest for you. Remember, during long runs, you’ll need to choose the approach that requires minimal thinking on your part.

How to eat according to time

As a general approach, start refueling 60 minutes into your run. Then aim to eat every 45 minutes for the rest of the run. [5]

However, some runners prefer eating a very small amount every 15 minutes. For example, rather than consuming a whole sports gel every 45 minutes, they might drink a third every 15 minutes.

Experiment and do what works for you!

How to eat according to distance

You can also refuel according to distance depending on your average pace of running.

For example, if your average 1 mile run time is 10 mins per mile, eat your first snack after 6 miles.

Thereafter, time your second snack 4 to 5 miles later depending on how you feel.

Other tips to help time your snacks

Use familiar landmarks

If you are familiar with the course, use familiar landmarks to time when to eat a snack. For example, you might run past a certain shop or a statue after a certain distance. You can use that landmark to remind you to eat.

Set a timer on your running watch

Use your running watch to set reminders as to when to eat or drink. This could be after an hour or every half an hour depending on the pace.

How much to drink while running

Staying hydrated before and during a run is essential to your health and performance.

How much you sweat during your run can vary depending on the temperature, intensity, and your level of fitness.

Not being hydrated properly can lead to dehydration and symptoms such as blood pressure problems, increased heart rate, and increased body temperature. Severe dehydration can cause weakness and confusion. ^[7]

To make sure that you are properly hydrated for your run, it’s important to make hydration a priority before your run. Generally, men need about 3.4 L per day, and women, 2.6 L per day. ^[8]

However, keep in mind that this can vary quite a bit so it’s good to check your hydration levels by using a Runners Urine chart.

The best way to stay hydrated during your run is to plan when you will be drinking. You can either choose to sip as you feel thirsty or plan when you’ll be drinking based on your average sweat loss.

For intense runs for longer than 90 minutes, a planned hydration program is more effective. ^[9]

For example, you can work out your average sweat rate and plan to sip every 15 to 20 minutes throughout the race. Include electrolytes or salt in your hydration strategy. Not only can this help prevent cramps but it can also help to avoid drinking too much water. Drinking too much water can cause an imbalance in electrolytes which can lead to a dangerous condition called hyponatremia. ^[10]

How to work out your average sweat rate

Use shorter runs to work out your average sweat rate to get an estimate of how much fluid you’ll need for longer runs.

Weigh yourself before and after a run.
Any weight you’ve lost will most likely be due to perspiration.
Work out your average sweat rate per hour of running
Calculate how much liquid you need to carry on your run to replenish fluids during the run.

For example, a 1-hour test run shows that I lose 1.5Ibs of water. Therefore, my sweat rate is about 30 fl oz per hour (0.8 L). For a 3-hour run, I would need to carry 90 fl oz (2.5 L) in my backpack.

As a general guideline, after your run, you need to drink about 1.5L of fluid (50 fl oz) for every kilogram (2.2 pounds) lost in body weight. ^[11]

Sports drinks can be useful here because not only will they replenish electrolytes, but they also contain carbs to keep your energy up. ^[12]

Examples of electrolytes

Sports Drinks

Diluted Orange Juice

Electrolyte Powder

Coconut Water

Sports drinks
Orange juice plus an equal part of water plus a teaspoon of salt
Electrolyte tablets or powder
Coconut water plus an equal part water, raw honey, juice of a lemon and a pinch of salt

What happens if you don't eat while running?

Running for more than 90 minutes, at more than 60% maximum heart rate, without eating can lead to you hitting the wall also known as bonking. ^[7]

Hitting the wall can be caused by many factors. However, one of the main causes is that your body runs out of energy in the form of carbs which forces you to slow down so it can turn fat into fuel. ^[13]

What does hitting the wall feel like?

Sudden and extreme fatigue
Loss of energy
Heavy legs
Muscle aches as if you have the flu

One of the best ways to prevent this is to make sure you’re getting enough carbs before and during your run. You should eat a fist-sized portion of complex carbs 4-6 times in the 24 hours before doing an endurance run and eat 30 – 90g of fast-release carbs per hour running. ^[5]

What not to eat while running

Your gut needs blood flow to digest and process food properly. Running diverts blood flow from the gastrointestinal tract (GI) to the muscles, lungs, and heart which is why it’s important to eat foods that are easy to digest and absorb.

About 30 – 50% of athletes in endurance events experience gut issues. This has been attributed to eating and drinking the wrong foods before a run, a lack of proper hydration, changes in nervous activity, hormones, and blood flow in the GI system. ^[14]

Avoid eating any foods that are hard to digest or that your body might react to. For example, if you usually experience bloating after eating salad, it’s best not to have salad in your pre-run meal.

Lastly, if you’ve overindulged, avoid trying to “burn off” your meal. You’ll end up feeling sick and bloated half way through your race.

What not to eat during a run

High-Fiber Foods

Fatty Foods

Spicy Foods

Dairy

High-Fiber Foods

These foods take longer to digest and can lead to bloating, cramps, and diarrhea during your run.

Beans of all types
Broccoli, Brussels sprouts, cabbage, cauliflower and kale
Berries
Apples
Lentils
High-fiber, wholegrains

Fatty Foods

Fat takes a long time for your body to break down. Your body will divert energy from your run to digestion, resulting in you feeling uncomfortable and sluggish.

Cheese
Red meat
Bacon

Spicy Foods

Spicy foods irritate your stomach and can lead to heartburn and gastrointestinal distress.

Chili
Curries
Anything spicy and hot

Dairy

If you find dairy hard to digest and generally don’t do well with dairy, it’s best to avoid it before a run.

Milk
Cheese
Yogurt
Ice cream

Sugary Drinks and Foods

While sugary drinks and foods like candy and pastries give you a burst of energy, you can quickly crash, leaving you feeling drained and shaky during your run.

Sodas
Candy
Pastries and cakes
Donuts

Coffee and Tea

While a moderate amount of caffeine can improve performance, too much can upset your gut, and leave you feeling jittery and anxious. ^[15]

Stick to one cup of coffee or tea in the hour before your run.

How food is used as fuel

Your body breaks down food into carbohydrates, fats, and proteins. Carbohydrates are broken down further into glucose which is released into the bloodstream.

Your body converts glucose into a molecule called ATP (adenosine triphosphate) to cause your muscles to contract.

Metabolism - turning food into muscle power

Your body can’t store much ATP, so it needs to be continuously created during exercise.

Your body creates ATP via a combination of two methods. The duration and intensity of the exercise determine which method is used the most.

Without oxygen – your body creates ATP during high-intensity exercise (such as a short sprint) without needing oxygen.
With oxygen – your body creates ATP during longer exercise sessions by using oxygen to break down fat.

Your body breaks food down into carbohydrates, fats, and proteins.
During low intensity runs, ATP is mainly created from fat
During higher intensity runs, ATP is mainly created from carbs stored as glycogen
Protein is primarily used for repairing muscles after a run

Without oxygen

During short, high-intensity sessions (less than 2 minutes), your body quickly converts glucose that’s already in your bloodstream into ATP. The downside to this is that it builds up lactic acid which is the burn you feel in the muscles when performing high-intensity exercise.

If you run for longer than 2 minutes, your body will need to switch to using oxygen to burn fat to create ATP.

With oxygen

During runs that are longer than 2 minutes, your body uses oxygen to convert carbohydrates and fat into ATP. This is a slower method of producing energy because it needs oxygen to be transported to the muscles.

Oxygen is needed to burn fat. When exercise is low-intensity, the body uses oxygen to burn fat. As the intensity of the exercise increases, the body switches to glycogen for energy because there is less oxygen in the blood.

Regular training can help with fat burning because, when you train, your body produces more capillaries which means that more oxygen can be delivered to the muscles to burn fat.

Calories stored in glycogen

Carbohydrates are stored as glycogen in your muscles and liver.

During higher-intensity runs, this glycogen is used to create ATP to fuel your muscles.

When fully fueled, most people have 90 mins – 2 hours worth of glycogen which is why you need to eat while running for longer runs.

Your body convert carbs to glucose then stores it as glycogen in your muscles and liver.
Most people have 1,500 to 2,000 calories of carbs stored as glycogen
Most people run out of glycogen after 90 mins - 2 hours
You can avoid glycogen depletion by eating carbs during your run or slowing down.

You want to prevent running out of glycogen, but how much does your body store?

Most people store 375-500g worth of carbs as glycogen, you can see from the calories per gram calculator that works out to 1,500-2,000 calories.

This means assuming you start with full glycogen stores, you can run for about 90 minutes to 2 hours at a moderate to high intensity before running out of glycogen.

If you start with low glycogen levels, due to being on a low-carb diet for example, you’ll run out much quicker.

Some studies have shown that women tend to rely more on fat for energy during endurance events, making men more likely to deplete their glycogen stores at a slower pace than women. ^[16]

Your rate of calorie burn will be influenced primarily based on your weight and speed.

Use the calories burned running calculator to understand your own rate, for example:

Someone of 140lbs running 12 miles at a 10 min/mile pace (2 hours) burns 1,400 calories.
Someone of 190lbs running 12 miles at an 8:45 min/mile pace (1h 45mins) burns 1,700 calories

How to avoid glycogen depletion

You can avoid glycogen depletion by ensuring you’ve eaten sufficient carbs in the 24 hours before your run so that your glycogen levels are full.

Rather than eating huge meals, aim to eat smaller more frequent meals so the carbs can be absorbed. You should aim for a fist-sized portion of complex carbs 4-6 times in the 24 hours before your run to maximize your carb stores.

If running for longer than 90 minutes you should also take a snack or consume extra carbs during your run. Aim for 30-90g per hour. Work out what fueling strategy works best for you. For example, you might feel better having a small snack every 15 minutes or find that every 30 to 45 minutes is easier.

Lastly, slowing down the intensity of your run will allow your body to switch from burning carbs to running off your fat fuel source for energy.

Diet considerations

There’s no “one snack for all” when it comes to what to eat while running.

If you have specific dietary needs or considerations, there are plenty of options out there.

Try alternatives but stick to your familiar snacks and pre-run meals before a big event or race. During your run, only choose snacks that you’ve tried on long runs before, don’t try something new.

Avoid foods that you are allergic to

When choosing what to eat while running, make sure that you’ve read all the ingredients and avoid anything that you might be allergic to.

For example, if you are allergic to raisins, rather opt for dates or energy-bars.

Choose snacks that you enjoy eating

It’s mentally challenging enough to run for longer than 90 minutes as it is. Don’t add to the challenge by forcing yourself to eat something you don’t like.

You want to reduce as many challenges as you can so that you can focus all your energy on completing your race. For example, if you don’t like the texture of energy gel, choose options such as an energy sports drink or dates instead.

Experiment with options during your runs

Use long practice runs to experiment with different things to eat while running. By the time you come to your race, choose a tried and tested option that works well for you.

Common mistakes when eating while running

Common mistakes when eating while running include eating too close to the run, eating rich or fatty foods during your run, or not eating enough.

While there is some experimentation in working out what works best for you before and during a run, there are some common mistakes that you can easily avoid.

For example, eating fatty, spicy foods just before or during your run can have a disastrous result halfway through so it’s best to keep the curry for a post-run meal.

Here are some of the most common mistakes:

Eating just before a run

Timing your pre-run meal or snack can make a world of difference to your run. Eating just before you run off into the sunset can leave you feeling heavy and bloated.

Eat light-easily digestible snacks for 30 – 60 minutes before you run. Meals should be at least 1 – 2 hours before your run.

Not eating enough before or during a run

While running in a fasted state can help with burning fat, not eating enough before a run can cause you to feel tired and you might even hit the wall.

During long runs, make sure you have a tried and tested fueling strategy in place to prevent this from happening.

If you are trying to lose weight, the best way to go about this is to eat a healthy, balanced diet with a slight calorie deficit throughout the week. Before your run, refuel with a healthy snack that is part of your diet.

Overloading on carbs before or while running

Excessive pre-race fueling can lead to you feeling bloated and sluggish. The same goes for eating during your run. Choose small bite-sized options to eat while running instead.

Drinking too much water

Drinking too much water can dilute electrolytes and also cause sloshing during your run.

Hydrate in the days leading up to your run and sip strategically during your run.

Eating protein-heavy snacks

Proteins take longer to digest so eating a protein-heavy meal before your run or during your run can leave you feeling full and heavy.

Ignoring food sensitives

If you are sensitive to a particular food or food group, the sensitivity won’t magically disappear during your run. It’s best to avoid eating any food that you’re sensitive to.

Not drinking enough liquid

Not drinking enough liquid can lead to dehydration during and after your run. Proper hydration before, during, and after your run can prevent this from happening.

FAQs

What should I eat before a run?

Choose easily digestible carbs and a small portion of protein, about 2-3 hours before your run. In the 24 hours before your run, eat 4 to 6 meals with a fist-sized portion of complex carbs. This will help build up glycogen stores in your muscles.

Do I need to eat during a short run?

No, for runs that are less than 60 minutes, there’s no need to eat while running.

What's the best thing to eat during a long run?

Fast-release carbs are a good option. Aim for 30 – 60g of carbs per hour. Ideas include sports gels, sports drinks, energy bars, raisins or dates.

What should I eat after a run?

Eat a combination of carbs and protein within 30 minutes of your run. Focus on eating healthy options to refuel and provide your body with all the nutrients.

Can I drink water while running?

Yes, it’s very important to drink water while running. Aim to sip water at least every 15 to 20 minutes and include electrolytes to avoid an imbalance.

Sources

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