Just like a car, our body needs energy to move forward. A car creates energy through the combustion of petrol. For our body the equivalent of petrol is glycogen (mostly coming from carbohydrates and fat).
We often read that if you fuelled correctly before a race, you have about 3hr of glycogen storage available:
This is true for an aerobic effort: Effort under threshold intensity (threshold is roughly the maximum intensity you can hold for one hour)
This isn’t true for an anaerobic effort (above threshold intensity), in this case you will go through your stock much quicker.
In this training topic we will look at efforts of 90min or more. Shorter events usually don’t require any nutrition intake.
How much and which nutrition should you take per hour?
Carbohydrates are the most efficient fuel, much easier to process than fat or proteins. We will focus on them in the race nutrition plan.
While exercising most of our blood flow goes towards our muscles. Our digestive system is no more a priority, it will function at a lower capacity than usual. This is why even during “easy” efforts you will burn more calories than you are able to ingest.
Most people can digest up to 60gr of carbs per hour when exercising. Each athlete being different, some will manage 100gr/hr while others only 20gr. You can first practice with 60gr/hr, then adjust according to your feelings.
To know the content of carbs in your nutrition, simply check the packages.
If you exceed your optimal rate of carbs/hour you might experience stomach distress. This is why it is important to have regular intakes, aiming at 15-30gr every 30min. If you take a gel of 30gr after 1hr, it won’t be recommended to eat a bar of 50gr/carbs 30minutes later.
Which type of products should you use?
This is very personal, but there are some rules:
Choose products with a high ratio of carbs:
If a 60gr bar contains 30gr of carbs = 50% of carbs
If a 35gr gel contains 30gr of carbs = 85% of carbs
Avoid excess in fibres, they take longer to digest.
Mix types of carbs: Glucose, fructose… (for people that digest correctly fructose)
According to sports you might have different nutrition plans. On a bike you won’t have the vibrations that you experience while running, you can eat more solid foods. While in running you will tend to choose gels or sport drinks.
What about hydration?
A great way to know how much water you need, is to do a sweat test. Weight yourself before an hour run, then do the same when you come back. If you lost 1kg, you sweated 1liter. Reproduce this test through the year in warmer conditions or at different intensities, you will have a great picture of your hydration needs.
You will try to replace your fluid loss, but tolerate 1 or 2 litres loss over the race. The longer the event the more importance hydration will take.
To avoid stomach distress, you want to drink every 10 to 15minutes, this way your stomach will have time to process all the liquid before you drink again. A person can usually process about 0.5l to 1l of water per hour, you can train your capacity to process more if you target events in warm climate.
Electrolytes or not?
This is a very tricky question, researchers and runners don’t always agree on this subject. Some people will tell you it is vital for a long effort, some like me do not add any in liquids. If you use electrolyte tabs, I recommend you follow the recommendations available on brands websites.
If your sweat is excessive or very salty (white marks on clothing after exercise), you can consider adding salt tablets to your nutrition plan.
My nutrition plan for a 5hr race:
Products I use:
Gels (30gr of carbs), without fructose.
Maltodextrin diluted in my water (30gr per 600ml).
Note: I can digest about 45gr of carbs per hour. Sweat about 0,6l per hour if I am cold.
Each hour I will take 1 gel and drink about 300ml of water. This makes 45gr of carbs per hour.
For hydration, I will sweat 5 x 0,6 = 3 litre and drink 1.5 litres