Although it’s a simple concept, fuelling for a marathon is a delicate balance. You want to consume enough calories on the go to give your muscles the extra energy they need to power you through several hours of running, but you want to avoid consuming too much so you don't suffer from stomach cramps and potentially have to make several stops in the portaloos.
Without extra fuel, you can run for about 90 to 120 minutes before bonking (AKA hitting the wall). This can be increased with efficient carb-loading, but you need to top up your fuel tank during your run in order to avoid the dreaded wall. Here are our top tips for fuelling your first marathon:
The most important aspect of marathon nutrition is discovering what works for you through a process of trial and error. You cannot expect to just wing it on the day.
Practice fuelling on your long runs and you will have a chance to see which types of fuel (gels, bars, drinks) work for you, which brands and flavours you can stomach and how often you can cope with consuming them. If you finish your long runs feeling completely shattered you need to take on more fuel next time. Finish feeling bouncy and you’re doing well on the fuelling front.
2 Time it right
There’s no point in waiting until you are running on fumes before chowing down on your first gel. On your long runs and on race day, aim to eat something after about 45 minutes of running. In training, start by taking on 30 grams of carbs (roughly 1 gel) every 45 minutes.
This can be increased up to 60 grams of carbs per hour, but your stomach can’t absorb carbs any faster than this. It’s not about cramming in as many carbs as possible but about finding your sweet spot, where you can run most efficiently on just the right amount of fuel.
3 Experiment with fuel types
Gels, blocks, liquids, gummy chews: they all contain simple sugars which are absorbed at roughly the same rate. Test out some different types and see what works for you. You’ll need to wash down a gel or block with some water – don’t be tempted to have it with a sports drink or you will probably find you are taking on too much sugar for your poor stomach to absorb at once.
If you intend to drink the sports drink provided by the race, find out which brand it is and experiment with drinking it in training. It's also worth experimenting with different foods. If sugary gels don't work for you, the humble banana can go a long way, or try muesli bars or flapjack. Most running stores sell a selection of different types of run fuel, or head over to our recipe section for run snack inspiration and make your own.
4 Take it slowly
If you find food hard to stomach, try consuming it more slowly over a period of several minutes, rather than gulping it down. Take on your fuel of choice just before a water station so you can sip fluids to help with the absorption.
5 Stay hydrated
Start drinking early, don’t wait till you are dehydrated as otherwise your body will have a harder time absorbing the fuel you’re taking on. Drink a little water at each water station. Don’t overdo it either, if you gulp too much water you are likely to get stomach cramps. For more race day advice read our hydration tips
6 Fine tune your pre-race nutrition
Try to eat a high-carb, low-fat, low-fibre dinner the night before your long training runs and before race day. Go for a high-carb breakfast with some protein, perhaps toast or porridge and a banana.
But most importantly, stick to what you know works and don’t be tempted to try anything new on race day. Good luck!