Marathon Nutrition Mission

How to fuel and refuel your well-oiled marathon running machine
◷ 3 minute read. In a hurry? Scroll down for our 60-second summary

fuel marathon training

As your training runs get longer, nutrition becomes increasingly important. If you fuel longer runs properly, they will start to feel more comfortable. The added endurance you’ll get could pull you through a few miles more than you thought you were capable of. That sounds good, doesn’t it? However, it’s not quite as straightforward as that. As you prepare to make your marathon debut it’s important to know what your body reacts well to and what it will – for want of a better word – reject. The only way to find this out is with a bit of logic and a bit of experimentation.

Carb Loading

Carbohydrate loading (commonly known as ‘carb loading’) is a very common strategy used by runners, intended to maximise the storage of glycogen (or energy) in the muscles and liver. Carb loading is one of the joys of marathon training. Think of the number of miles you are about to run. Now divide it by 10. This is the number of days you should carb load for in advance of a race or long run. So for a marathon it’s about two and a half days, for a 20 miler it’s two days. You get the idea. Carb loading is three meals with some decent complex carbs (search the internet for examples of these – there are many, it isn’t just pasta!) and two snacks per day. Your body will thank you if they’re low in fat and low in sugar. Definitely avoid sugar and citrus in the 12 hours or so before your run as they may bring on a stitch. And for goodness sake, don’t try anything new in the 24 hours before a race!


It’s important to ‘prehydrate’ before a run, so drink plenty of liquid beforehand. Stop drinking one hour before the last time you can go to the toilet before the run. If you’re running from home, that’s an hour before you leave. If you’re at a race, you’ll need to allow extra time to get from the toilets to the start line. I’ve said an hour to be on the safe side. You may find you need a bit longer than that or you may get away with less. Now’s the time to experiment and get to know your kidneys!

Drinking On The Run

The great thing about doing a Spring marathon is that you build your mileage during the winter. Good choice! (If you’ve stumbled across this blog whilst training for an Autumn marathon when you’re trying to run for a long time on hot summer days – I feel your pain!) You’re going to ask how much you should drink on a run, aren’t you? Several studies have looked at this and, sadly, there isn’t a definitive answer – there are way too many variables to get to an accurate, one-size-fits-all figure. There are obvious dangers to being dehydrated. However, there are also dangers to being over-hydrated; from the relatively minor discomfort of a stitch or needing a wee to the far more dangerous condition of hyponatremia. The best answer I can give you is that you should drink little and often from pretty early on in your run – don’t wait until you’re thirsty to start.

What should you drink? Water is good. If you can stomach a sports drink then this is better. A sports drink will replenish some of the carbs you’re rapidly burning and supply electrolytes which can help lower the risk of a cramp or nausea. You may find that sports drinks give you a stitch, though, so experiment well in advance of race-day, and if you do have issues, try watering them down. Sports drink stations at marathon events are usually watered down. To be really prepared, find out what sports drinks will be on offer during the marathon you’ve entered and experiment with them to see how your stomach reacts.

Energy Gels

The Oxford English Dictionary defines ‘manna’ as ‘spiritual nourishment’. Energy gels are the manna of the marathon runner! As far as the long distance runner is concerned, the human body has a serious design fault – it can only store enough carbohydrates for 90 minutes of fast-ish running or two hours of marathon pace running. One way to combat this is to use energy gels, which will help replenish those lost carbohydrates. They can be taken every 45-60 minutes and must be taken with water – although SIS gels can be taken alone.

There are three reasons to experiment with energy gels on training runs: 1) they’ll improve your performance; 2) you’ll find out what gels agree with your stomach; 3) until you’ve opened a sachet and squeezed it into your gob whilst running, you won’t realise how difficult this is! Practise beforehand to avoid crusty white flakes all around your mouth in your race day photos.


If you need a lot of liquid on the run you may want to invest in a Camelbak or similar product. But here’s a tip for you – plan a route where shops will be open on the way, slip your contactless debit card in your pocket and take a couple of bottle-of-water/sports-drink pit stops along the way. Sadly, you’ll be far less likely to find shops selling energy gels, so an energy gel belt is a good idea. Or you could go for the cheaper option of taping your gels to your arms. This gives you the added bonus of almost weightless running in the final few miles after you’ve finished the last one. NB – If you have hairy arms, maybe this option isn’t for you…


As soon as you feel able to after a long run, get some healthy protein in you – this could be as simple as some nuts and a banana. The first thing you eat should be something your weary muscles will be grateful for. (This does not include cake but feel free to treat yourself to that a little later.) You’ll then need to carb re-load with a similar meal to the ones you ate before the run.


Take some time to experiment and evaluate your body’s response during your training runs. How was your stomach on that run? Did you eat too soon before running or could you have squeezed in another snack 90 minutes before the run? How did the gels work? Did you take enough water with you? Think about your fuelling strategy. If something went well or badly make a note of it and keep it in your race plan or change your strategy accordingly. There is no magic formula that suits everybody; it takes practice, experimentation and a bit of patience.

what you need to know
  • The miles in your long run/race divided by 10 equals the number of days you should carb load beforehand

  • Hydration is important – whilst running drink little and often, but not too much

  • Don’t underestimate refuelling on recovery – eat a healthy protein snack as soon as possible then a carb heavy meal after that

what you need to do
  • Get to know your stomach and kidneys – what pre-run food will give you a stitch and how soon before a run do you need to stop drinking to avoid the dreaded ‘wee-in-a-bush’?

  • Find out what energy gels and sports drinks will be given out in the marathon you’ve entered. Try these out on training runs. If they don’t agree with you, try diluting them with water

  • If you need to take your own energy gels, invest in a gel belt or try strapping them to a (non-hairy) arm

Share With Your Running Buddies!