Race day nutrition is an art form and if you get it wrong it can completely ruin a race. Getting cramp, diarrhoea of sickness can add an hour or more to your race but also make it miserable.
As an athlete I’ve made every mistake in the book! And as I’ve got older I’ve no longer got a stomach made of steel so really need to think about my nutrition. In my last Ironman race I took a gel I wasn’t used to and my run went downhill from there! It was grim and added at least an hour to my run time!

The mistakes I see most among athletes I coach are not practicing nutrition, not having a plan and not reviewing the plan after the race.
I recently took the time to review my race day nutrition with a calculator and all the nutrition information. It was pretty clear I had not taken enough nutrition on at all so no wonder I suffered through the run.
So here are a few tips about nutrition
Practice, practice, practice! You can train your gut to tolerate nutrition products so practice in training and with practice races.
Have a detailed plan. If you have a plan then you’ve got something to aim for and you’ll know during the race if you’re on track or behind on your targets.
The detail of your plan should include carbohydrates per hour, litres per hour, sodium intake. When, and how (e.g. are you carrying it or using on course nutrition).
Review your plan post-race. What did you actually do compared to what you planned.
If you suffer with GI issues it can often be caused by too much nutrition and sugar so work out the sums before your race.
Other things that can cause GI issues include intolerance of fructose (try something kinder on your gut), dehydration, taking on too much in one go rather than spreading it out over the course of the event.
Never try anything new on race day that you haven’t tried out before.
Current research shows that endurance athletes should be aiming for 60g of carbs per hour.
Think about how much you sweat. Do a sweat test before you race so you have some idea of if you’re a heavy sweater or not. Being soaked through compared to your friends and regularly having salt patches on your clothes are usually signs of either being a high sweater or having salty sweat. Have a look here for more information.
Have a plan A, a plan B and a plan C. If you start feeling sick then adjust the plan!
Consider reducing your fibre intake in the few days leading up the race e.g. avoid beans, lentils, brown bread etc.
Training causes stress to your body including your gut. It’s a good idea to make sure you have a healthy gut on a day to day basis and definitely in the lead up to the race so that your stomach can cope with the extra stress on race day. This can include taking a pro-biotic as well as eating foods such as live yogurts.