Carbs for Runners: What to Eat Before, During and After

Carbs for runners are essential for energy, endurance and recovery. Discover how your body processes carbohydrate and exactly how much to eat before, during and after running.

Carbohydrates have become unnecessarily controversial.

Some runners increase them before every training session. Others avoid them because they believe eating fewer carbs will improve fat burning or help them become lighter.

The reality is more practical: carbohydrate is one of your body’s most important energy sources, particularly when running becomes longer or faster.

You do not need to consume huge bowls of pasta before every easy run. However, consistently under-fuelling demanding training can leave you with heavy legs, falling pace and poor recovery.

The key is matching your carbohydrate intake to the work you are asking your body to perform.

THE SHORT ANSWER

Carbohydrates are broken down primarily into glucose. Your body can use that glucose immediately or store it as glycogen in your muscles and liver.

When you run, muscle glycogen and blood glucose help produce adenosine triphosphate, or ATP – the energy that allows your muscles to contract.

Your body also uses fat while running, especially at easier intensities. As your pace increases, however, carbohydrate becomes increasingly important because it can supply energy quickly enough to support faster running.

As a broad starting point, runners may need approximately:

3–5g of carbohydrate per kilogram of body weight daily on rest days or during light training.
5–7g/kg daily during moderate training.
6–10g/kg daily during heavy endurance training.
30–60g per hour during runs lasting roughly one to two-and-a-half hours.
Up to 90g per hour during longer events, provided this has been practised in training.

These are guidelines, not compulsory targets. Your needs depend on your training volume, intensity, body size, goals and tolerance.

Carbs for runners provide essential energy for training and recovery. Learn how much carbohydrate to eat before, during and after running.

WHY DO RUNNERS NEED CARBOHYDRATES?

Carbohydrate is particularly valuable to runners because it supports exercise intensity.

Your body holds much larger reserves of fat than carbohydrate. Fat can provide substantial energy during easy running, but converting it into usable energy is comparatively slow.

Carbohydrate can produce ATP more rapidly. That makes it especially important during:

Tempo and threshold running
Interval sessions
Hill repetitions
Long runs
Marathon-pace training
Races
Days containing more than one training session

Research consistently shows that carbohydrate availability and timing can influence endurance performance, training quality and recovery. Sports nutrition guidance therefore recommends adjusting carbohydrate intake to reflect the demands of each session rather than consuming the same amount every day. Academy of Nutrition and Dietetics, Dietitians of Canada and ACSM

HOW DOES THE BODY TURN CARBS INTO RUNNING ENERGY?

The process begins before you take your first step.

1. CARBOHYDRATE IS DIGESTED

Carbohydrate-containing foods include bread, rice, pasta, potatoes, oats, fruit, cereals, milk, yoghurt, beans, sports drinks and energy gels.

During digestion, most carbohydrates are broken down into simple sugars. Glucose is absorbed through the small intestine and enters the bloodstream.

Carbohydrate provides approximately four calories of energy per gram.

2. GLUCOSE ENTERS THE BLOOD

Some glucose can be used immediately by your cells. After a meal, insulin helps move glucose out of the bloodstream and into tissues.

During exercise, contracting muscles can also increase their uptake of glucose. This helps working muscles access fuel even as the body’s hormonal environment changes.

3. EXCESS GLUCOSE IS STORED AS GLYCOGEN

Glucose that is not required immediately can be joined together and stored as glycogen.

Most glycogen is stored in two places:

Muscle glycogen supplies fuel to the muscle in which it is stored.
Liver glycogen helps maintain blood-glucose levels between meals and during exercise.

A well-fuelled athlete may hold approximately 300–400g of muscle glycogen and 80–100g in the liver, although actual amounts vary with body size, diet, training status and recent exercise. Unlike body-fat reserves, glycogen stores are relatively limited. Fundamentals of glycogen metabolism

4. GLUCOSE IS CONVERTED INTO ATP

Inside the muscle cell, glucose or glycogen passes through a series of chemical reactions beginning with glycolysis.

At easier and moderate intensities, the resulting products can enter the mitochondria, where oxygen helps the body produce a larger amount of ATP.

At higher intensities, the demand for ATP rises rapidly. The body consequently relies more heavily on carbohydrate metabolism because it can deliver energy faster than fat metabolism.

ATP then powers the repeated muscle contractions that move you forwards.

5. GLYCOGEN IS RESTORED AFTER RUNNING

After exercise, carbohydrate helps replenish the glycogen used during the session.

How urgently you need to replace it depends on when you are training again. A runner with another demanding session later that day has a greater need for rapid refuelling than someone taking the following day off.

DO YOU BURN CARBS OR FAT WHILE RUNNING?

You nearly always use a mixture of both.

During easy running, a larger proportion of your energy may come from fat. Carbohydrate is still contributing – it has not been switched off.

As the pace increases towards threshold or race intensity, the proportion supplied by carbohydrate generally rises. Your body requires energy more quickly and carbohydrate is better suited to meeting that demand.

This is why a runner may feel comfortable jogging slowly before breakfast but struggle to complete hard intervals at the expected pace without adequate fuel.

Being good at using fat does not remove your need for carbohydrate. A well-trained endurance runner should be metabolically flexible: able to use fat effectively at lower intensities while accessing carbohydrate when the pace demands it.

HOW MUCH CARBOHYDRATE DO RUNNERS NEED EACH DAY?

Daily carbohydrate requirements should reflect your current training load.

Training demand	Daily carbohydrate guideline
Rest day or light activity	3–5g per kg of body weight
Moderate training of around one hour	5–7g/kg
Endurance training lasting one to three hours	6–10g/kg
Very high-volume endurance training	8–12g/kg

These ranges are deliberately broad. The upper end is generally more relevant to high-volume athletes than to recreational runners completing three or four sessions each week.

EXAMPLE FOR A 70KG RUNNER

A 70kg runner’s approximate ranges would be:

Training demand	Approximate daily carbohydrate
Rest or light day	210–350g
Moderate training	350–490g
Heavy endurance training	420–700g
Extreme training volume	560–840g

Calculate your range by multiplying your weight in kilograms by the relevant gram-per-kilogram target.

For example:

70kg × 5g = 350g of carbohydrate

Remember that 100g of cooked rice is not 100g of carbohydrate. Food contains water, protein, fibre and other nutrients, so use nutrition labels or a food-tracking tool if you need a more accurate estimate.

Most runners do not need to count every gram indefinitely. Tracking two or three representative days can simply show whether your intake is broadly appropriate.

SHOULD CARBOHYDRATE INTAKE CHANGE EACH DAY?

Yes. This is sometimes called carbohydrate periodisation.

A short recovery run does not require the same amount of fuel as a two-hour long run. Your plate can therefore change with your programme:

Rest or easy day: use the lower end of your carbohydrate range.
Interval or threshold day: increase carbohydrate before and after training.
Long-run day: eat more carbohydrate the day before and around the session.
Race week: increase carbohydrate as training decreases, particularly before a half marathon or marathon.

Periodising carbohydrate does not mean deliberately starting every easy run with low glycogen. It simply means placing more fuel around the sessions that matter most.

HOW MANY CARBS SHOULD YOU EAT BEFORE RUNNING?

For an important long run, race or demanding workout, sports nutrition guidance commonly recommends 1–4g of carbohydrate per kilogram of body weight during the one to four hours before exercise.

The closer you eat to the run, the smaller and easier to digest the meal should generally become.

For a 70kg runner, that range could mean:

Approximately 70g eaten one hour beforehand
Approximately 140g eaten two hours beforehand
A larger meal eaten three or four hours beforehand

You do not have to force down the maximum amount. Choose a quantity that suits the session and your digestive tolerance.

PRE-RUN CARBOHYDRATE IDEAS

Three to four hours before running:

Porridge with banana, honey and toast
Rice with eggs or chicken
A bagel with jam and a bowl of cereal
Pasta with a light tomato sauce
Potatoes with a lean protein source

Thirty to sixty minutes beforehand:

A banana
Toast with jam
A small cereal bar
A sports drink
A few chews or half an energy gel

Before a relaxed run lasting less than an hour, you may not require additional carbohydrate if you have eaten normally during the day. Hunger, session timing and personal preference still matter.

HOW MANY CARBS DO YOU NEED DURING A RUN?

Your requirements depend on the duration and intensity of the run.

Running duration	Suggested carbohydrate approach
Less than 45 minutes	Usually none required
45–75 minutes at high intensity	Small amounts or a carbohydrate mouth rinse may help
1–2.5 hours	Approximately 30–60g per hour
More than 2.5 hours	Approximately 60–90g per hour when practised

For prolonged endurance exercise, consuming carbohydrate can support blood-glucose availability and preserve performance. Intakes approaching 90g per hour generally require products containing more than one carbohydrate source – commonly glucose or maltodextrin combined with fructose. Carbohydrates for training and competition

Higher intake is not automatically better. A runner who normally consumes 30g per hour should not suddenly attempt 90g per hour on race day.

Your digestive system needs time to adapt.

WHAT DOES 30–60G OF CARBS PER HOUR LOOK LIKE?

The exact amount depends on the product, so always check its label.

Approximately 30g could come from:

One larger energy gel
One standard gel plus several mouthfuls of sports drink
A serving of chews
A banana combined with a small amount of sports drink

Approximately 60g could come from:

Two gels
One gel and a bottle of higher-carbohydrate sports drink
A mixture of chews, drink and real food

Calculate your total from everything you consume. If your drink provides 30g per hour and two gels provide another 50g, your actual intake is 80g – not 50g.

Our guide to how energy gels work and which type to choose explains how to compare different formulations.

DO YOU NEED 90G OF CARBS PER HOUR?

Probably not for every run.

Intakes of up to 90g per hour are most relevant during marathons, ultramarathons, long cycling events and high-volume training. They can help some athletes sustain performance, but they also require planning and gut training.

For many recreational runners, gradually progressing towards 40–60g per hour is a more realistic starting point.

Practise your strategy during long runs by gradually increasing either the serving size or frequency. Test the same products, fluids and timings you intend to use on race day.

If you frequently experience bloating, nausea or an urgent need for a toilet stop, reduce the amount temporarily and assess the concentration, hydration, product type and timing.

HOW MANY CARBS DO YOU NEED AFTER RUNNING?

If your next demanding session is more than 24 hours away, a normal carbohydrate-containing meal is usually sufficient.

For example:

Rice, vegetables and chicken
Pasta with tomato sauce and tuna
Potatoes with eggs and salad
Porridge, fruit and yoghurt
A sandwich, fruit and milk

When rapid recovery is necessary – such as between two sessions on the same day – guidance suggests approximately 1–1.2g of carbohydrate per kilogram per hour during the first three to four hours.

For a 70kg runner, that equals around 70–84g per hour.

Combining carbohydrate with a source of protein supports overall recovery and muscle repair. The urgency matters less if you can eat a complete meal soon and have plenty of time before your next hard session. International Society of Sports Nutrition position stand

WHAT HAPPENS WHEN RUNNERS DO NOT EAT ENOUGH CARBS?

Occasionally completing an easy run with lower carbohydrate availability is not the same as being chronically under-fuelled.

Repeatedly failing to replace the energy used in training may contribute to:

Heavy or unresponsive legs
An inability to reach normal training paces
A sudden drop in pace during long runs
Slower recovery between sessions
Persistent hunger or strong food cravings
Poor concentration and irritability
Disrupted sleep
Increased illness or injury risk
Menstrual-cycle changes
Declining motivation and performance

These signs are not specific to carbohydrate deficiency, and some can have medical causes. Persistent symptoms should be discussed with an appropriately qualified healthcare professional.

Read our guide to the eight warning signs of underfuelling in runners for a broader look at energy availability.

IS “HITTING THE WALL” CAUSED BY RUNNING OUT OF CARBS?

Low carbohydrate availability is an important part of the problem, but the explanation is not as simple as a completely empty fuel tank.

During a marathon, muscle glycogen falls while liver glycogen helps maintain blood glucose. If carbohydrate availability becomes too low, maintaining your intended pace becomes increasingly difficult.

However, marathon fatigue is multifactorial. Pacing errors, heat, dehydration, muscle damage, low blood glucose, psychological fatigue and insufficient training can all contribute.

Carbohydrate cannot rescue an unsustainable pace. It helps support the pace your training has prepared you to run.

If you are preparing for a marathon, our carb-loading guide for runners explains how to increase glycogen without simply overeating the night before.

SHOULD RUNNERS TRAIN WITH LOW CARBOHYDRATE?

Selected low-intensity sessions with reduced carbohydrate availability can increase some cellular signals associated with endurance adaptation and fat metabolism.

That does not mean low-carbohydrate training automatically produces better race performance.

Starting a hard session under-fuelled may reduce your speed, power, total training volume and ability to recover. Repeating this frequently can also increase the risk of inadequate energy intake.

If you want to experiment, use a low-risk session:

Choose a short, genuinely easy run.
Do not use the approach for intervals, threshold work or important long runs.
Eat normally afterwards.
Stop if you feel dizzy, unusually weak or unwell.
Avoid it if you have a history of disordered eating or a medical condition affecting blood-glucose control.

For most runners, consistently completing high-quality training will be more useful than forcing every run to become a test of carbohydrate restriction.

ARE ALL CARBOHYDRATES THE SAME?

All digestible carbohydrates ultimately provide energy, but different foods serve different purposes.

EVERYDAY CARBOHYDRATE SOURCES

Most of your regular intake can come from nutrient-rich foods such as:

Oats and wholegrain cereals
Rice, pasta and potatoes
Bread and wraps
Fruit
Beans and lentils
Milk and yoghurt
Root vegetables

These foods can also provide fibre, vitamins, minerals, protein and beneficial plant compounds.

SPORTS CARBOHYDRATES

Gels, chews, sports drinks and lower-fibre foods are useful when you need fuel that is portable and digested quickly.

They are tools, not automatically better foods. A gel makes sense halfway through a marathon but is rarely necessary while sitting at a desk.

Close to a race, reducing fibre and fat may help some runners tolerate their pre-event meal. During ordinary daily eating, unnecessarily restricting fibre can reduce overall diet quality.

SEVEN COMMON CARBOHYDRATE MISTAKES

1. EATING THE SAME AMOUNT EVERY DAY

Fuel should broadly follow training demand. Your long-run day and rest day do not have identical requirements.

2. RELYING ON GELS WHILE NEGLECTING DAILY FOOD

Race fuel cannot compensate for starting a session with poorly stocked glycogen stores.

3. FUELLING EVERY SHORT, EASY RUN

Most runners do not need a gel for a relaxed 30-minute run. Save sports nutrition products for sessions where they offer a practical benefit.

4. UNDER-FUELLING HARD TRAINING

Intervals, threshold sessions and long runs are precisely where carbohydrate can help you maintain quality.

5. COPYING ELITE INTAKES IMMEDIATELY

An elite marathon runner consuming 90g per hour has usually developed that strategy over years. Build your intake gradually.

6. SAVING ALL YOUR CARBS FOR THE NIGHT BEFORE

Carbohydrate availability reflects your wider eating pattern. One enormous pasta dinner cannot correct several days of inadequate fuelling.

7. TRYING SOMETHING NEW ON RACE DAY

The best fuelling plan is one you have already tested at race intensity.

A SIMPLE CARBOHYDRATE PLAN FOR RUNNERS

Instead of chasing a perfect number, begin with five steps:

Estimate your daily range using your body weight and training load.
Place more carbohydrate around harder sessions and long runs.
Eat a familiar carbohydrate-rich meal before key training.
Practise 30–60g per hour during longer runs, increasing gradually if necessary.
Eat a balanced recovery meal containing carbohydrate and protein.

Monitor your energy, training quality, hunger, recovery and digestive comfort. Adjust the plan using those results.

THE RUNNER’S JOURNAL VERDICT

Carbohydrates are not a shortcut to better running, but they allow your body to make better use of the training you complete.

Your muscles store carbohydrate as glycogen. Your liver uses it to support blood glucose. During running, these fuels help generate the ATP needed for muscular contraction – particularly as the pace or duration increases.

The goal is not to maximise carbohydrate at every meal. It is to make enough fuel available for the work ahead.

Eat less on genuinely light days, more around demanding sessions and practise your race strategy before you need it. That is more effective than either fearing carbohydrates or consuming sports fuel indiscriminately.

CARBS: FREQUENTLY ASKED QUESTIONS

How many carbs should a runner eat each day?

A broad starting range is 3–5g per kilogram of body weight on light days, 5–7g/kg during moderate training and 6–10g/kg during heavier endurance training. Your appropriate intake depends on training volume, intensity and total energy needs.

Do runners need carbs before every run?

No. A short, easy run may not require additional carbohydrate if you have eaten normally. Pre-run carbohydrate becomes more valuable before long runs, races and demanding workouts.

Is running without breakfast bad?

Not necessarily. Some runners comfortably complete short, easy morning runs before breakfast. It is less suitable for hard or prolonged sessions and should not become a way of repeatedly avoiding necessary energy intake.

How many carbs should I eat before a long run?

Guidelines suggest 1–4g/kg during the one to four hours before exercise. Start with a familiar meal that fits your schedule and digestive tolerance rather than forcing the maximum amount.

How many carbs should I take during a marathon?

Many runners aim for 30–60g per hour, while well-practised athletes may progress towards 60–90g per hour. Test your target during long runs and include carbohydrate from gels, drinks, chews and food in the total.

Are energy gels better than real food?

No, but they are more convenient during faster running. Gels provide a measured amount of rapidly available carbohydrate in a portable format. Real food may work equally well when it is practical and well tolerated.

Do carbohydrates make runners gain weight?

Body-weight changes are influenced by overall energy balance, not carbohydrate alone. Glycogen storage also attracts water, so increasing carbohydrate can temporarily raise scale weight without representing an equivalent gain in body fat.

Can you run a marathon without taking carbohydrates?

Some runners may finish without them, but that does not make it the best performance strategy. Consuming carbohydrate during prolonged running generally helps maintain blood glucose and delays fatigue.

What is the best carbohydrate for runners?

There is no single best source. Use minimally processed, nutrient-rich foods for most daily meals and easily digested options such as white bread, rice, sports drinks or gels when speed and digestive comfort matter.

REFERENCES AND FURTHER READING

This article provides general educational information and is not a substitute for individual medical or nutritional advice. Runners with diabetes, gastrointestinal conditions, food allergies, a history of disordered eating or other clinical concerns should seek guidance from an appropriately qualified professional.