What to eat and supplement while marathon training
Written by Martin Ebner,
Last updated October 2026
Marathon training has a lovely habit of turning hunger into a moving target. Some days you’ll finish a long run ready to eat the furniture. On others, your appetite disappears just when your body needs food most.
The answer isn’t a perfect meal plan or a cupboard full of supplements. You need enough total food, more carbohydrate when the training demands it, regular protein and a fuelling routine that you’ve tested before race day.
Your watch can track every kilometre. It can’t tell you whether you’ve eaten enough to recover from them.
EAT FOR THE TRAINING YOU’RE DOING
Your nutritional needs change across the week. A rest day, an easy 30-minute run and a two-hour long run don’t require identical amounts of food.
As the mileage increases, your energy intake usually needs to follow it. If the training load keeps rising while the food stays the same, recovery becomes harder and performance may begin to suffer.
Trying to lose weight aggressively during marathon training is rarely a clever combination. Being lighter doesn’t automatically make you faster if you’re also under-fuelled, tired and struggling to recover. The IOC consensus on low energy availability connects prolonged under-fuelling with poorer health and performance in both male and female athletes.
This isn’t about diagnosing yourself with a syndrome because you had one tired run. It’s a reason not to treat constant hunger and exhaustion as proof that the training is working.
CARBOHYDRATES DO MOST OF THE HEAVY LIFTING
Carbohydrate is the fuel your body relies on heavily when you run at a meaningful pace. You store it as glycogen in your muscles and liver, then use those stores during training.
Sports-nutrition guidance generally places runners around 5 to 7 grams of carbohydrate per kilogram of bodyweight on moderate training days. Demanding endurance days may require 6 to 10 grams per kilogram. The nutrition and athletic-performance position paper gives wide ranges because the correct amount depends on training volume, intensity and the individual athlete.
You don’t need to hit one fixed number every day. Eat more carbohydrate before and after harder or longer sessions, then slightly less when the training is easier.
Rice, pasta, bread, oats, cereal, potatoes, fruit, beans and dairy can all contribute. Sports drinks, gels and chews also count when convenience and digestion matter.
Carbohydrates aren’t something you earn by completing the run. They help you complete it properly in the first place.
PROTEIN STILL MATTERS
Running doesn’t remove the need for protein. Your muscles, tendons and the rest of the body still need material to repair and adapt.
Around 1.4 to 1.8 grams of protein per kilogram of bodyweight per day is a sensible working range for many runners. You don’t need to eat it all at dinner. Spread it across three or four meals and give each meal a useful serving.
Meat, fish, eggs, yogurt, milk, tofu, beans, lentils and protein powder can all work. What matters most is the total amount you manage consistently.
Protein powder is convenient when your appetite is low or you’re rushing out after a session. It isn’t superior to food and it doesn’t need to appear in every meal. Think of it as a safety net.
I’ve explained the wider numbers in Protein for fitness goals: how much do you need?
DON’T TRY TO REMOVE FAT FROM THE PLAN
Dietary fat supports normal health, makes food enjoyable and provides useful energy. Marathon training isn’t a reason to live on skinless chicken and sadness.
Olive oil, nuts, seeds, avocado, eggs and oily fish can remain part of the diet. The only time I’d usually reduce fat is close to a run, particularly if a large or rich meal tends to sit heavily in your stomach.
The same applies to fibre. It belongs in your normal diet, but enormous servings immediately before a long run can turn the planned route into a search for the nearest toilet.
WHAT TO EAT BEFORE A RUN
Not every run needs a carefully engineered pre-run meal. If it’s short and easy, your normal eating pattern may be perfectly adequate.
Before a longer or harder session, carbohydrate becomes more useful. The standard guidance allows roughly 1 to 4 grams per kilogram during the 1 to 4 hours before exercise. The closer you are to the run, the smaller and easier to digest the meal should usually become.
If you have several hours, porridge with banana and honey, cereal with milk, toast with eggs or a rice-based meal may work well. If you’re running soon, toast with jam, a banana, a small bowl of cereal, fruit juice or a sports drink may be more comfortable.
There’s no prize for forcing down breakfast at five in the morning if it makes you feel ill. A smaller snack before the run and a proper meal afterwards may suit you better.
The best pre-run meal isn’t the one that looks most impressive online. It’s the one that gives you energy without making itself known halfway around the route.
FUEL LONG RUNS WHILE YOU’RE RUNNING THEM
For a short run, you probably don’t need gels hanging from every available part of your body.
Once a session moves beyond roughly 75 to 90 minutes, consuming carbohydrate during the run becomes more useful. Current endurance carbohydrate guidance suggests around 30 to 60 grams per hour for prolonged exercise. Events lasting more than two and a half hours may benefit from amounts approaching 90 grams per hour, normally using a mixture of carbohydrate sources.
That could come from gels, chews, a sports drink, bananas or other food you can carry and tolerate. The format matters less than getting enough without upsetting your stomach.
Start practising this during training. If you intend to consume a gel every 30 minutes during the marathon, your long runs are where you find out whether that plan works. Race day shouldn’t be the first meeting between your stomach and six energy gels.
EAT AFTER THE RUN
You don’t need to sprint from the finish of every session to a protein shake before an imaginary anabolic window slams shut.
If you’re training again soon, eating promptly becomes more useful. If the next session is tomorrow or later, a normal meal within the next couple of hours will usually do the job.
Build that meal around carbohydrate and protein. Rice with chicken and vegetables, pasta with meat or lentils, potatoes with fish and salad, or a sandwich with yogurt and fruit can all work. The meal doesn’t need a special ratio or a photograph.
If your appetite vanishes after a long run, start with something easier. A smoothie containing milk or yogurt, fruit, oats and protein powder can give you something useful until you feel ready for a proper meal.
There’s more detail in Post-workout nutrition: what to eat after training.
HYDRATE WITHOUT FLOODING YOURSELF
Hydration matters, particularly during long runs and hot weather. More water isn’t automatically better, though.
Your fluid needs depend on temperature, pace, body size, sweat rate and how salty your sweat is. The National Athletic Trainers’ Association position statement recommends individualising fluid intake while avoiding both significant dehydration and excessive drinking.
Drink when you’re thirsty and learn from training. If you finish a long run desperate for water, you may need to carry more next time. If your stomach is sloshing and you’ve forced down litres because somebody gave you a fixed target, you’ve probably gone too far.
Electrolytes may be useful during long or hot sessions, particularly if you sweat heavily or leave white salt marks on your clothes. They aren’t required in every bottle of water, and swallowing electrolyte tablets doesn’t cancel out excessive drinking.
The goal is to replace what you’re losing, not win a hydration contest.
WHICH SUPPLEMENTS ARE WORTH CONSIDERING?
Food and the training plan decide far more than supplements. The IOC consensus on sports supplements found good performance evidence for only a relatively small group of ingredients, and even those need to fit the athlete, the event and the situation.
Carbohydrate products: Gels, chews and sports drinks are useful because they make carbohydrate easier to carry and consume. They’re practical race fuel, not nutritional wizardry.
Protein powder: Useful when food is inconvenient or your appetite is low. If you already eat enough protein, adding more won’t make you recover twice as fast.
Caffeine: Caffeine can improve endurance performance, but the response varies. More isn’t always better, especially if it causes anxiety, stomach trouble or destroys your sleep. Test it during training and remember to count coffee, gels and pre-workout products together.
If you prefer a measured, lower-caffeine pre-workout, Pre Lab Pro contains 80 mg per serving. That may be useful before a harder session, but it isn’t carbohydrate fuel and it won’t replace breakfast or your long-run nutrition.
Iron: Don’t take iron because running makes you tired. Fatigue has plenty of possible causes, and unnecessary iron supplementation can cause problems of its own. If you’re concerned, particularly if you menstruate, follow a plant-based diet or have a history of low iron, speak to your doctor and get the appropriate blood tests first.
Beetroot and nitrate: These may offer a small benefit in some endurance settings, but the results vary between people. If you experiment, test the same product and timing during training. Don’t build the entire race plan around it.
Omega-3, Boswellia and multivitamins may have a place when your diet or health creates a specific need. They aren’t compulsory marathon supplements and they shouldn’t be used to cover up inadequate food or poor recovery.
A PRACTICAL LONG-RUN DAY
This isn’t a rigid meal plan. Portion sizes need to match your bodyweight, appetite and the session ahead.
Before the run: Porridge with banana and honey, or toast with jam and a bowl of cereal. Add yogurt, milk or another protein source if you have enough time to digest it.
During the run: For sessions beyond 75 to 90 minutes, practise taking 30 to 60 grams of carbohydrate per hour through gels, chews, drinks or food. Drink according to thirst and the conditions.
After the run: Rice, pasta or potatoes with a useful serving of protein, vegetables and some salt. If food feels difficult, start with a smoothie or yogurt and fruit.
Later in the day: Return to normal meals. Keep carbohydrate available, include protein and don’t try to compensate for the run by barely eating afterwards.
The plan should be flexible enough to survive work, family, travel and the occasional meal that isn’t nutritionally perfect. Consistency beats an immaculate spreadsheet that lasts four days.
RACE WEEK IS A DIFFERENT JOB
Everyday marathon nutrition supports the weeks of training. Carb loading is a specific strategy for the final day or two before the event.
Don’t spend the entire training block eating as though the race is on Sunday. When the time comes, follow the full carb-loading guide and use foods you’ve already tested.
Nothing new on race week. No heroic portions, no mystery supplement and no breakfast recommended by somebody who has never met your stomach.
FUEL THE WORK YOU’RE ASKING YOUR BODY TO DO
Marathon nutrition doesn’t need to dominate your life. Eat enough overall, move carbohydrate up and down with the training, include protein regularly and practise your long-run fuel before race day.
Supplements can make parts of that more convenient. They can’t replace the food, the training or the recovery.
If your running watch can tell you your vertical oscillation but you’re still unsure what to eat after two hours on your feet, Check It Oot is where I sort the useful fitness advice from the noise. One email once or twice a month, written by me and delivered straight to your inbox.
