It is well known that carbohydrate is THE nutrient for athletes, the more I take, the more energy I will have! Nope ? Well, like everything in nutrition, it depends on the context! We cover it all here:
1 - Carbohydrates and energy intake
First of all, it is important to note that carbohydrates are one of the 3 macro-nutrients, that is to say the large molecules that bring you energy by being "burned", thus generating kilocalories (which basically gets you going). The other two are lipids (fats) and proteins.
When you start a physical effort, your muscles will start using a very fast source of energy, phosphocreatine (we will come back to this in a future article). Just remember that this system allows muscle contractions for about fifteen seconds, then another form of fuel takes over: bingo, carbohydrates!
Carbohydrates are therefore all “sugars”, “slow” sugars (starch), maltodextrins, and “fast” sugars such as sucrose (table sugar) or fructose.
During the first 40 minutes of effort, carbohydrates will be the main source of your effort, beyond that you enter the aerobic window:
Aerobics is the state of effort where the majority of your energy will come from small radiators in your cells, we call them mitochondria. These little wonders will, thanks to the supply of oxygen from your breathing, begin to “burn” a maximum of carbohydrates but also lipids! This is when you really go into trail mode and your body is ready for the effort.
2 - Glycemic balance
So you are now in 'burning mode' ready to swallow D+! Now the important thing will be to manage your contributions well according to your profile and the type of effort! In aerobic mode, your body uses carbohydrates but especially lipids (in the form of fat reserves). Lipids come from your muscles (and yes, athletes have muscle fat) and fatty tissue throughout your body.
NB: On a marathon for example, 40% of the energy consumed comes from lipid reserves.
What you have to understand is that the more time passes, the more the body burns reserves, and therefore it is important to provide some energy through food to support the effort. The more intense the effort, the more carbohydrates will be needed because they will pass quickly into the blood. On a longer trail in a rolling portion, you can also recharge with "slower" carbohydrates and a little easily digestible fat! (Example: Tuc + County die)
The most important thing is not to bring too many carbohydrates at once! Too much sugar or too sudden an arrival in the body risks disturbing your glycemic balance (blood sugar level), causing nausea, and "breaking" your rhythm.
3 - Establish a race nutrition protocol
In general, the need for carbohydrates through food or drink in the race can be estimated at:
- 1st hour: 0 to 25g
- 2nd hour: 30 to 40g
- 3rd hour: up to 60g
- Beyond 3 hours and depending on the intensity of the effort, you can go up to 70 or even 90g/h.
The more intense the effort and the more time passes, the more the need for carbohydrates increases, because the body's reserves are reduced.
For a good carbohydrate intake that will not cause your blood sugar to explode, I recommend that you bring about half of the carbohydrates in the form of starch or maltodextrins (therefore sugars with a medium assimilation rate) and the other half with rapid assimilation like pure sugar, or fructose.
When the effort becomes too painful, that's when fast sugars can save you! We will then favor carbohydrates from honey, compotes, or sucrose which will be absorbed much more quickly.
For example, a bar based on oats and dates with 25g of carbohydrates including 12g of 'sugars' will be perfect in the middle of a portion at medium effort, while a portion in D+ at the end of the race will deserve a very sweet gel, a compote, or a piece of fruit.
And There you go ! You now know more about carbohydrates for trail running, I hope these tips will help you on your next events!
Mathys Loridan - Holistic Dietitian and Sports Nutritionist
Find Mathys on Instagram