Should I stack carbs?


You will undoubtedly have heard of carbohydrate stacking. What exactly is this and when does it make sense to do it before an important event or race? In this article, we’ll go over the do’s and don’ts.

Carbohydrate Storages

At low intensity, a trained endurance athlete can get his or her energy mainly from fats. However, even at low intensity, part of the energy will always come from carbohydrates and this proportion increases as the intensity increases. So these carbohydrates are the primary source of energy at high intensity. How long you can sustain this high intensity depends mainly on the amount of carbohydrates stored in the body. So it sounds logical to make sure this supply is as large as possible before the starting shot.


You can store about 600 to 750 grams of carbohydrates in the body at most. These carbohydrates are stored in the form of glycogen in the liver and muscles. This amount can be used for a maximum of 90 minutes at full throttle or FTP and then it is used up. So for most cycling activities, just making sure your stores are full before departure is not enough. You will also need to try to keep replenishing carbohydrates while cycling.

Maximize replenishment

In the old days, the tried and true method was to first completely deplete the stores by training hard and eating as little carbohydrate as possible for a week beforehand, then to replenish the storages substantially. We now know that the storages can be replenished to the same point without the depletion first. The only thing you need to do is to reduce the training load considerably for a few days and increase the carbohydrate intake.


The reduction of training load is also called “tapering”. It ensures that you are well rested for the moment suprême. Because you’ll also miss some training, you don’t want to make this period too long. How long exactly is very personal. Some people feel better with five days of very calm training, while others only want one or two rest days to feel fresh and well-rested.

24-hour stacking

To ensure that the maximum capacity in the muscles and liver is used for glycogen storage, 8 to 10 grams of carbohydrates per day is recommended in the 24 hours before the event. For many cyclists this is not much more than the normal daily consumption. Especially in the Western world we eat quite a lot of bread and pasta. A common mistake is to pile on more carbohydrates than that and especially more. Everything you can’t store is stored as fat and that’s of little use to you as a cyclist.

Weight gain

What you should keep in mind is that every gram of stored carbohydrate is accompanied by 3 grams of water. So with a full tank of carbohydrates you also drag along 2 liters of water. Therefore, stacking carbohydrates really only makes sense for very long hard efforts and is better left out for a short race or time trial.

Eating too much

Another common mistake is to eat huge amounts of carbohydrates on the day itself. The night before D-day, the carbohydrate stacking should have been completed. On the morning itself, a ‘normal’ breakfast with about 60 to 90 grams of carbs should be sufficient. Make sure you have eaten up to about 2 hours before the start and avoid fats and proteins in the morning. These overload the digestive system. You can have a sports drink (carb-loader) with around 40 grams of carbohydrates in the two hours before departure, but more is really not necessary. With a huge stack of pancakes you actually eat yourself out of chances before it even starts.

Eat a variety of foods

Finally, it is very important to stack carbohydrates in a varied way. After all, you absorb carbohydrates best when they come from many different sources in many different forms. Especially the slower carbohydrates that your body absorbs more slowly, such as brown rice, spelt pasta and whole grain bread, your body can better store in glycogen.
If you want more information nutrition advice you can contact our sports dietician Mariette or check out our personal nutrition plans over here. If you want to be better prepared for your event you can check out our coaching services our download our app JOIN Cycling.