Race fuelling is an important consideration for the marathon. Generally speaking, if you’ve had a decent carby dinner and breakfast, most people have enough glycogen (The way carbs/energy are stored in your muscles) to see you through to about 18-20 miles.
(Yep, this means you don’t really need them for a half marathon, though they do provide a useful boost as a placebo)
Obviously this leaves a shortfall of 6-8 miles for your body to find juice for. So you’ll need to consume more energy whilst you are running to see you through the extra miles. Of course, you can’t stop for dinner on the way around, so you need to consume your energy on the move.
You also need to remember that the carbs you take on board won’t be ready for your muscles to use straight away. It takes time for them to digest and convert to glycogen so your muscles can use them. So waiting until you’ve made it to 18 miles to start taking fuel on will be too late. Common sense dictates you should start fuelling early on, at regular intervals so your body never runs out of glycogen in the first place.
So what do you take to fuel yourself? Well some people take flapjacks, jelly babies or a manner of other things. Personally I use energy gels. They are small and easy to carry (Some are, anyway) and more importantly, easy to consume. I’m not sure I’d get on too well trying to chow down on flapjack at marathon pace!
Gels however are very rich, vary widely in flavours and also vary as to how much energy they actually give you per pack. I read some horror stories about people who try gels and they simply do not agree with them, causing ‘runners tummy’ – not nice to be caught short with that mid marathon!
You need to find a gel that you like the taste of, sits well in your tummy, and provides the right amount of carbs for your needs. The only way to work that out is through experimentation, and practise. And the best time to do that is on your long run.
Firstly, pick a brand (With various flavours) and get a few individual sachets of a gel and stick with that brand for a long run. See how your tummy reacts during that run, and see how you feel at the end of it. It’s no good mixing brands, if you have a bad reaction to one its impossible to tell which caused it! When you have tried them out, ask yourself these questions
Did you feel sick? Need the toilet? If its a no to those then your digestive system agrees with them.
Did you like the flavour? Many brands have a range of different flavours to experiment with, as long as your tummy agrees you can try different ones.
Were you able to open them OK? Silly question, but when you are running at speed and reaching mile 22, your coordination isn;t what it used to be! You want to be able to open them easily and with confidence that you won’t drop what could be your last gel!
Can you carry enough? Think about how many you’ll need for the full 26.2 and how you are going to carry them? I have a SPI Belt with 6 gel loops which is enough for me to have one every 4 miles with one spare for droppage. Do you have capacity to carry them?
Can you run with that many gels? Make sure you have a practise run with all the gels you’ll need loaded in your transport system. When I ran Paris, I had never worn the gel belt, and it felt incredibly weird carrying a heavy waist pack. I wish I’d have tried it first!
If you find a gel which meets all those requirements, get a box of them (as they are cheaper in bulk) and keep practising with them. Your body will get more used to them and you’ll be able to work out how frequently you need to use them, if you need water with them etc.
I tried SIS Go (didn’t like the taste), Clif Shot Bloks (Tasted great, but struggled to shew and breathe whilst running at marathon pace) and finally settle on Gu. Thick and syrupy, but very tasty. Small to carry on my gel belt and also light. Easy to open and easy to consume. My order is with Wiggle as we speak!