Getting your fuelling strategy right in training and racing is very individualized and a crucial piece of the performance puzzle. Correctly fuelling our effort is a really important aspect of good performance. It’s well researched and recognized that our bodies can store enough carbohydrates in liver and muscle glycogen for 90 minutes to 2 hours of exercise, particularly at lower intensities.
Exercising for longer than this, or at significantly high intensity, requires us to ingest carbohydrates to maintain performance. Our carbohydrate requirements are very individualized. It is also intensity dependent, with higher intensity effort requiring more carbohydrates.
There is specific testing you can do to work out your carbohydrate requirement at certain intensities, but many athletes rely on a little bit of trial and error to drill down on this number. Using a race simulation later in your race prep is a great starting point for working out your approximate carbohydrate burn rate while operating at a given intensity.
Much of the research has arrived at a few general rules that apply. It’s considered that somewhere between 30g to 90g per hour is required once you start operating at moderate intensities and particularly over 2 hours in duration for the higher end of that range.
As mentioned above, this is very athlete dependent. There’s also been research showing that gut absorption—how much carbohydrate can be absorbed through the gut and into your bloodstream—differs greatly from athlete to athlete and is often the limiting factor. Once again, this highlights the importance of individualizing your strategy and also training your gut at the upper level of what you are aiming to ingest.
Take-home message: recognise the importance of practicing your nutrition/fuelling strategy in a race simulation.
When I was preparing for races, particularly longer-distance events, I always sought the advice of nutrition experts when establishing my hydration and nutrition plans. We often spend so much time, effort, and money preparing for these events—making sure our training is correct, having all the right equipment, etc.—so it just made sense to ensure that planning around fuelling and hydration was just as intentional.
