Here’s how to fuel before, during, and after your marathon.

“In the marathon build, it can be easy to underfuel, which can increase your risk of injury,” says Taylor Merloni, a registered dietitian at Mindful Miles. So, what should you eat for success? Merloni recommends “Eating a meal or snack every 2-3 hours. Meals should have a source of carbohydrates, protein, fat, and fruit or vegetables. Snacks should be at least 2 of these food groups.”

It’s easy to overlook the importance of nutrition during your marathon training. But as James Rodgers, Elite runner and running coach, says, “Quality nutrition is fundamental to sustain the demands of training. You need to ensure you adjust your intake of calories, particularly carbohydrates and protein, for muscle repair.”

And then there’s your nutrition during the marathon – what you eat to keep your energy levels high and to stop you from hitting the wall. We’ll cover that shortly.

In this article, we provide the ultimate guide to marathon nutrition with advice from an Elite runner and two qualified nutrition experts.

Nutrition for Marathon Training 

Alex Oskian, MS, RDN and nutrition coach at Working Against Gravity, re-emphasizes the importance of eating enough calories to support your increased activity levels during marathon training.

Mileage increases significantly throughout your training plan, and some of those training efforts can take multiple hours, increasing your energy expenditure throughout the week. Eat enough calories, specifically carbohydrates and fat, to support the energy demands of your run training.

Cutting body fat through a calorie deficit is not the main focus during marathon training. Instead, save body composition goals for the off-season. Fueling the body adequately throughout your training will help reduce injury risk and improve recovery and adherence to training paces.

A diet filled with whole food sources should be prioritised, as these foods provide vitamins and minerals and can help reduce muscle cramps and stress fractures. Magnesium-rich foods include:

  • Spinach
  • Dark chocolate
  • Avocado
  • Black beans
  • Nuts/seeds
  • Bananas 

Foods high in vitamin D, calcium, and vitamin K can help strengthen the bones and reduce your risk of stress fractures.” Example foods include:

  • Tofu
  • Berries
  • Leafy greens
  • Salmon
  • Sardines
  • Bone broth
  • Fortified milk
  • Dairy products

Once you’ve got those ticked off, do your best to eat a well-balanced diet and remember to increase your daily calorie intake as needed to support your training efforts.

Practise your race-day nutrition 

During your training, it can help to practise your race-day nutrition. Rodgers suggests, “Simulating your race morning in your training as much as possible. For example, you may start the session, particularly your long run, at the same time of day that your marathon is scheduled. This will allow you to get a feel for things such as how long to eat and drink before your run.”

If you have already tried out various sources of carbs and know the exact timing, you can simply trust “muscle memory” to do the work for you. Just focus on running while sticking to the game-day nutrition that you have already dialled in during your training. It can be helpful during training runs to pay extra attention to the timing of your pre-run meal (including what is in the meal as well as how you felt during the run),” says Oskian.

Remember that anxiety and nerves can affect your stomach on race day, so having a pre-practised nutrition strategy can help massively.

What to eat before a marathon

In the week leading up to your marathon, eat more carbs than normal. You don’t need to enter a carb-induced coma – but increasing your carb intake ensures your glycogen stores are full.

You can replace some of your daily calories from fats to carbs. If you are prone to gastrointestinal (GI) issues, reduce your fibre intake as needed in the days before the event.

Eat a mix of slow and fast-digesting carbohydrates to fuel your body for the marathon. Eat 3-4 hours before the race to allow for proper digestion.

Example breakfasts include:

  • Oats and berries
  • Bagels with your favourite toppings
  • Granola
  • Pancakes

Your breakfast should be the same meal you’ve been eating before your long run in your training. This helps train your stomach and reduces the likelihood of stomach issues during your run.

Nutrition during a marathon

One of the common mistakes first-time marathon runners make is not eating enough during their race. Eating and running don’t sound like they should go together, but you need to eat plenty of carbs to make it to the finish line.

So, how many carbs should you eat?

Merloni says, “A good goal is to aim for 60 grams of carbohydrates per hour, with some faster runners benefiting from more.” For example, an energy gel every 30 minutes works well. That’s x2 Styrkr GEL30s, each containing 30g of carbohydrates, or a GEL50, containing 50g, for a slightly smaller carb intake.

You can also include energy bars if you want to mix up your nutrition from energy gels. These are also great to use during your marathon training, especially during those long runs. The BAR50 contains 50g of carbohydrates and is fast to digest and easy on the gut.

You don’t have to eat energy gels and bars – but a lot of runners find these easier to eat and easier on the stomach than other carbohydrate sources, such as bananas, chews, or sweets. But eat whatever works best for you and your digestive system!

Furthermore, Merloni says, “Runners should also take in 10-24 oz of fluid, with electrolytes every hour.” The STL07 hydration tablets perfectly mimic the ratio of electrolytes in human sweat with added sodium to support your performance. Add electrolytes to your race day hydration plan to prevent cramps and stop you from hitting the wall.

Don’t try anything new

“It’s recommended not to try anything new on race day. This is because you may not know how your body will react to the food. Trying out new food may result in stomach cramps, GI upset like diarrhoea, or even the dreadful bonking, where you run out of energy too quickly,” says Oskian.

What to eat after a marathon

“After the race, you want to enjoy and treat yourself; however, consuming a good form of protein and carbohydrates within a 30-minute window allows you to recover from your marathon much faster and rehydrate the body with water and electrolytes”, says Rodgers.

You may find eating difficult after finishing, but even something small will help replenish your glycogen stores. It will also improve your recovery. A few hours after your race, have a sit-down meal – you will likely have a better appetite by this point.

Eat a well-balanced meal with plenty of carbs, protein, fats, and veggies. And don’t shy away from a celebratory dessert or a couple of drinks – you’ve earned it!

Mistakes to avoid

We asked Oskian about the most common nutrition mistakes she sees when coaching marathon runners – here’s what she said:

“A common mistake is to think that something that works for another person may also work for you. As every person is different, we all require different food sources (and quantities). Always try something during training to determine how it worked for you so you know if you need to try something else. 

Furthermore, another mistake is not considering the importance of hydration. Make sure to plan your hydration needs, not just water intake but consuming enough electrolytes as well. You can add salt supplements, but diligently salting food can work well too.”

Key Takeaways:

  • Practise your marathon nutrition in your training
  • Eat 60g of carbs/hour in your marathon
  • Don’t try anything new on race day
  • Drink plenty of water & take electrolytes if needed
  • FAQs

    How many gels do I need for a 4 hour marathon?

    Aim to consume two energy gels (30g of carbs each) per hour for eight energy gels. If needed, you can also eat whole foods, energy bars, and other foods.

    What should marathon runners eat?

    Marathon runners can eat energy gels, chews, energy bars, and foods such as bananas to fuel their marathon attempt.

    Is coffee good for a runner?

    Coffee before a run can improve your energy and reduce your pain perception. But test coffee out in training – you don’t want any nasty digestive issues during your marathon.