What to Eat When Running a Marathon

A good diet filled with the right nutrients is an essential part of any exercise routine, but it becomes especially important for endurance events like marathons or triathlons. Follow our tips to make sure you bound over that finish line…

The C factor – carbohydrate

‘Hitting the wall’ or ‘bonking’ is every distance runner’s fear. It might sound like an old wives’ tale, but it’s a phenomenon that can happen to anyone, no matter how much training you’ve done. It occurs when the body’s carbohydrate fuel tank – the body’s preferred energy source during high intensity activity that is stored in the muscles and liver as glycogen – gets low and the brain and muscles show signs of fatigue. If you hit the wall during a marathon you’ll know about it, every step feels like wading through treacle. You can avoid the dreaded wall by ‘carb loading’ before and during a run to maximise your energy stores, which means stocking up on lots of carbohydrate-rich pasta, potatoes, and certain fruits and vegetables.

The power of protein

Protein helps to rebuild muscle, so it is particularly important after a long run to repair damaged tissue and stimulate the development of new tissue. Good protein foods to eat after a run include milk, cheese and yoghurt, white meats and eggs.

Before long runs

A few hours before any long run, eat a meal high in low GI carbohydrates, moderate in protein and low in fat to give your body all the nutrients it needs for the next few hours. We recommend Quinoa porridge.

  • Gently warm 100g cooked quinoa in a pan with some unsweetened almond milk
  • Top with 1 chopped apple or a handful of berries
  • Serve with a sprinkle of ground cinnamon

During long runs

It’s important to replenish your carbohydrate stores during runs of 90 minutes or more. The body can only store around 2,000 kcals of glycogen and after a few hours of running, your fuel tank warning light will flicker on unless you frequently top up your carb stores. High GI carbohydrate foods are best during a run as they release energy quickly. Choose specially designed sport gels and isotonic drinks, or try bananas, oranges, honey, dried fruit or gummy sweets such as jelly beans. Fuel every 45-60 minutes during a long run, with around 30-60 grams of carbohydrate (120-140 calories) per hour (e.g. a large banana or white bread honey sandwich), and don’t forget to stay hydrated with plenty of fluids and electrolytes.

After long runs

You have a window of around 30 mins when the body is primed to replenish its carbohydrate stores and soak up muscle-repairing protein after a run.


  • A large, colourful vegetable salad with watercress, spinach, carrot, beetroot, tomatoes, fennel, mixed peppers, cucumber and, of course quinoa!
  • Chocolate milk is a good mix of protein and carbs, or whizz up a maca smoothie with lots of fruit.
  • Wild salmon steak or cod fillet served with plenty of green leafy vegetables such as kale, spinach and chard, plus courgettes, asparagus, leeks, carrots, broccoli, etc (melt some butter or coconut oil over the veg for a scrumptious finish)

Don’t forget to add chia seeds to drinks to replace nutrients and electrolytes lost through sweat.

What to Eat When Running a Marathon

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