Ironman Poland 2021 Nutrition Analysis

To understand what happened on the nutrition side in my Ironman Poland 2021, I’m doing some analysis in this article. Maybe it’s a little bit oversimplified, but I took the calories, which my Garmin Forerunner 935 displayed for this calculations. And I will only consider the calories taken in during the race. With this laid out let’s dive into it.

Garmin Forerunner 935 Calories (Output)

SportCalories / Cal

Calories Intake During the Race (Input)

Type of NutritionCaloriesNotes
7x UCAN bars (160 Cal)1120All eaten on the bike
1x bread roll with 1x slice of cheese310 + 113google search for bread roll and slice of cheese
1 UCAN Edge Gel70Eaten on the run
4x ca. 100ml Red Bull45One serving on each round on the run

Calorie Deficit

Calculating the difference from input and output, I had a calorie deficit from 4388 Calories. So there is no wonder that I was not able to run at my full potential. I already faded at the last kilometres on the bike, but I didn’t realize it, because the last 20 km where nearly only downhill.


On the bike I had a Profile Design FC35 System with ca. 1000ml (ca. 34oz) capacity and one normal water bottle with ca. 700ml (ca. 24oz). Every second aid station on the bike course, I grabbed a bottle of water (750ml, ca. 25oz). so in total I had around 1000ml + 700ml + 4x 750ml = 4700ml on the bike. On the run I took a drink (ca. 200ml, 6.7oz) at every aid station (4 rounds with 4 aid stations). Most of it was water and a little bit Red Bull.


Even if this calorie calculation is quite vague, it is clear that I underestimated my calorie requirement completely. I already started to realize it on the beginning of the run, but at that moment it was to late. I couldn’t eat the offered energy bars on the run course and the one supply station with Red Bull was not enough to kept me going at a decent speed. Hydration was not a problem. So for my next Ironman I will take much more food with me. I’m even thinking about placing a special needs bag at the designated area, to be able to get more food which I’m used to. Another thing is to get used to eat more while training on the bike and runs.

Swim Course

Bike Course
Run Course
UCAN Energy Bar

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