How to fuel a marathon – pre, during & post-race

If you follow me on Twitter or Facebook you’ll probably have heard me banging on about starting training in November for Brighton Marathon next April. Well, November’s here and I’m officially shitting it. But in a good way. 

I’ve been battling equal measures of pure terror and over-excitement at the prospect of getting stuck into some serious training – it’s just SUCH A LONG WAY to run, and I honestly don’t know if I can do it. But, I’ve ran two half marathons before, and never thought I’d ever be able to do that, so a full 26.2 *might* just be doable if I sort my knees out, put the work in and fuel efficiently, right? (Say yes Tess). 

Speaking of fuel, I’ve been sorting my nutrition out recently and am trying to eat clean, but have no idea where to start in terms of fuelling for the marathon distance. Step in the lovely people at the Supplement Centre, who have sent me over some tips for how to fuel efficiently before, during and after the marathon.

I’m especially excited about the three days of carb loading! 


How to fuel a marathon

how to fuel a marathon

With determination and
consistent, safe training it’s true that many people can acclimatise their
bodies to running the 26.2 miles of a marathon. However, it’s not all about
what we do with our bodies; what we put into our bodies is also a huge
contributing factor.

It can feel unnatural to
change lifelong eating habits, but if you want to make your marathon as fast
and fun as possible then it’s worth considering how you fuel your body.

Marathon nutrition can
be broken down into three main time spans:

  1. Pre-marathon
  2. During the
  3. Post-marathon


It used to be
recommended that the pre-marathon phase should begin approximately one week
prior to the big day. This school of thought has been replaced with a more short-term
approach of just 2-3 of days, otherwise known as ‘carb loading’.

Carb loading marathon training
True story…

When we exercise our
bodies draw fuel from either glycogen in the muscles (which is a product of
carbohydrates) or fat. Fat however is a far less efficient fuel, it burns
slower. This means that when our bodies run out of glycogen and switch to fat
burning we ‘hit the wall’. Our legs slow down, fatigue
sets in and that elegant trot turns into a treacle-footed slog. To delay
hitting the wall as long as possible, savvy marathon runners ‘carb load’ to
ensure they have as much glycogen stored in their muscles as they possibly can.

Follow their wisdom by eating
plenty of carbohydrates for 2-3 days before your marathon – rice, pasta, oats –
anything with a high carb content should be packed in. As a rule of thumb
85-95% of your calories should come from carbs during this phase.

During the race

When you get to race
day, your muscles should be stocked up to the max with energy-giving glycogen.
However, unless you’re superhuman, that ‘wall’ will come at some stage during
your race. This is why sensible marathon runners carry some high-energy fuel
with them to top up the glycogen tank on race day.

Energy gel is a great
option – it’s far more compact than a drink and doesn’t disrupt your breathing
pattern like chewy energy bars or
supplements might. Start taking in small amounts after only 30
minutes of running, and then continue to steadily consume this fuel throughout
the race. Remember to keep taking in water to aid the replenishment of glycogen
into your muscles.


If you cross the finish
line, first thing’s first – give yourself a colossal pat on the back!
Completing a marathon is a fantastic achievement. However, your work is not yet
done. If you want to be able to walk properly within a few days, you’d better
start feeding those work-weary muscles.

Get a couple of energy
gel sachets into your system immediately. Follow them with a non-carbonated
sports drink and then get your hands on some carbs again! Keep stocking up your
system as you did before the race until you feel like a fully functioning
person again – keep going for at least a few days!

Overall, you might be a finely tuned athletic machine,
but you’re useless without the right fuel.

This is a guest post from the Supplement Centre.

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