Riders kept being told to eat too much or too little. The fix was to stop averaging the session and start reading it in blocks.
StemNotes came about after getting feedback from many of the riders I coach that the nutrition apps that they had been using to provide guidance were either suggesting they have too much or too little depending on the sessions that they were doing. This got me thinking, why wasn’t there a nutrition app available that looked at the actual workload and the fuel substrate source for the rider and provide fully tailored and individualised nutrition guidance based on their specific physiology?
Blocks, not a blanket rate
This led me to create a formula whereby the rider’s critical power was considered, and I would input the session details in blocks of 30 minutes based on normalised power for those durations. The reason for using normalised power is because it gives a more representative look at the internal workload combined with the external workload for the rider to produce the effort in each block.
The reason for doing this approach in blocks is that because a blanket grams per hour recommendation does not consider the variable intensity across different training sessions. There may be easier segments where you do not want to be consuming so much, followed by effort segments where you need to be consuming more.
The absorption ceiling
Of course, the limiting factor for carbohydrate intake is how much you can actually absorb. This is why the blocks are capped by a maximum grams per hour consumption rate which is individual to rider. If a block requires more carbohydrates to be consumed than can be managed, then the fuel load is frontloaded so as to be well prepared for any intensity later in a session. This ensures that the total carbohydrate intake is still adequate for the total workload of the session, both principles supported in up to date published research across sports nutrition.
Where the energy comes from
The next problem is that different riders have a different ratio of carbohydrate usage relative to the intensity of critical power that they maintain. It is not just about the total workload, but where that energy is being derived from. For example, a professional rider might still predominantly be burning fat at 80% critical power, however they are working often at a much higher power output so the total energy requirements are still high. An amateur would likely be burning a higher ratio of carbohydrates at this intensity but with the lower total workload the total amount of carbohydrates might still be lower.
Why biological sex matters
Another important consideration is that women tend to use different ratios of carbohydrates and fats at given relative intensities. This is why as well as having three different training status levels, we also have biological sex specific recommendations.
Built for one rider at a time
This is a nutrition app designed to fuel you based on your physiology and your training status as well as the specific sessions that you were doing. No blanket recommendations that have been applied to everyone, just one specific output that is designed specifically for you.
About the author
Andy Turner graduated with a first class honours degree in Sports and Exercise Science in 2021, with a particular interest in nutrition and dietetics. He has been coaching dozens of riders since 2017 and raced himself at elite and UCI level for multiple seasons. He combines a strong theoretical and scientific understanding with a deep understanding of the psychological and practical aspects of sports science application for athletes across all levels.