Planning Your Race Day Nutrition

Nutrition - the fourth discipline of triathlon. Such is the complexity of our nutritional needs that even top triathletes like Lionel Sanders can struggle to get them right. There are two key elements: fuel (calories) and hydration. In this blog we will focus on fuelling your body for optimum performance on the big day.

We are lucky in the 21st century - with our smart watches and heart rate monitors we have access to a veritable mountain of data that can help us estimate our fuelling needs. To estimate your calories per activity you can look back at your activities and intensity levels to plan your calorie requirements.

Depending on the event, the intensity levels of your activity will differ, and so will the amount of calories used from carbohydrates versus fats. Typically, for an age group athlete a full distance Ironman race will take place mainly Zone 2 while a 70.3 Ironman is more likely to center on Zone 3. Shorter distance races will be between Zone 3 and 4, with Zone 4 typically meaning the maximum effort you can hold for one hour.

2000. The Training Intensity Handbook for Endurance Sport. KinEli Pub. 

The other factor to consider is how much energy will you start with prior to the race if you are fully ‘topped-up’. By ‘topped-up’, we mean that you are already fuelled accordingly (as mentioned in our previous blog, ‘How to fuel during a training block’) and you that have had a breakfast to replace any calories you have burned since your last meal from the previous day.

Ideally, you do not want to go into a deficit during your race. You need to plan for a pretty consistent intake of nutrition throughout. Luckily, we only need to plan to replace the carbohydrates during the race, since even the leanest of athletes generally have more than enough fat stores to see them through the intensity of race day.

The following is an example for a 75Kg athlete with 15% body fat, racing an Ironman 70.3, where the intensity level will be Zone 3. Note that the time from the swim is deducted to determine the calories per hour as there is no opportunity to consume anything during that leg of the race. Using the chart above we can estimate the starting amount of calories from carbohydrates (stored as glycogen).

It is important to note that in general the body can only absorb about 60 grams (240 calories) of glucose per hour (all types of sugar except fructose). If the hourly requirements exceed that amount you need to use fructose as an energy source as well, which can add up to another 30 grams (120 calories) per hour. The caution would be that not everyone tolerates fructose very well, which can lead to stomach issues on race day – a far from ideal situation. It is important that you test your race nutrition prior to race day at race level intensities to see how your body tolerates your chosen fuel as it will differ under stress in comparison to your tolerance at rest or during an easy session.

All of these points are a general guideline. How your body absorbs and reacts to different fuel sources can be different. Calories burned calculated by your smart watch are also averages based on activity type, inputted body weight, and intensity.  There are lots of options for fueling but it is REALLY important you test out your race nutrition plan before race day.

Final tips for race day: make sure you maximize your nutrition on the bike. It is much easier to digest your nutrition on the bike versus on the run. If you are taking gels you can dilute them in a bottle of water and sip the bottle and ensure you empty it before the end of the bike leg. Don’t waste time in transition taking your nutrition; take your first gel once you have settled into your bike or run, about 10 minutes or so in to the leg. Use the timer on you watch to remind you to take in your nutrition on a regular basis. Most of all remember to have fun!

Email me at CoachMike@MAD4Tri.com if you have any questions. Also, I would love to hear your feedback.