The most common carbo-loading mistakes

Joëlle Flück 14. July 2022


The purpose of carbo-loading is to maximise the carbohydrate reserves in the muscles for longer loads. By increasing the supply of carbohydrates beforehand, more energy in the form of carbohydrates is available during the load.

What is carbo-loading?

Carbo-loading involves adapting your training and diet to maximise the storage of carbohydrates in your muscles (muscle glycogen storage) before (endurance) competitions. The technique was developed in Sweden in the late 1960s and typically included a 3-4 days muscle glycogen "depletion" phase and a 3-4 days "replenishment" phase. Further research, however, has made it possible to simplify the method.

When is carbo-loading beneficial?

Carbo-loading can be expected to improve your performance in endurance competitions that last longer than 90 minutes. These typically involve sports such as cycling, long-distance running, triathlon, cross-country skiing, or long-distance swimming. In the case of shorter competition times, any advantage is unlikely because the body’s normal carbohydrate reserves are sufficient.

How was carbo-loading originally done?

Classic carbo-loading, also called the Swedish diet, initially included a phase during which the glycogen stores were depleted. This lasted 3-4 days with (at least) two tough training units and a low-carb diet. At that time, it was believed that this depletion phase was necessary in order to fully replenish the glycogen stores. The depletion phase was followed by a 3-4 days replenishment phase which involved no training and a carbohydrate-rich diet.

How is carbo-loading done today?

Further research has shown that the depletion phase is not necessary at all. A significant reduction in training for 48 to 72 hours while following a diet that is extremely high in carbohydrates (10-12 g carbohydrates per kg body mass per day) is sufficient to fill up the muscle glycogen stores to the maximum.

  • Carbohydrate intake target: 10-12 g per kg body weight. At a weight of 70 kg, you would therefore need to consume about 700-740 g of carbohydrates.
  • Incorporate several snacks. It’s not possible to consume a sufficient amount of carbohydrates in just three main meals.
  • Carbohydrates can also be consumed in the form of fluids (fruit juices, sports drink, sweet drinks, regeneration shake, carbo-loader drinks, etc.).
  • Eat foods low in fat and protein. Carbo-loading requires eating a lot of carbohydrates. If you add a lot of fat and protein, it becomes too much.

What are the most common carbo-loading mistakes?

Some athletes don’t quite achieve the goal of carbo-loading. The following are the most common mistakes.

  • Carbo-loading requires a reduction in training.
  • Many athletes fail to eat enough carbohydrates. Working with a sports nutrition specialist or devising a «carbohydrate plan» can be helpful. A pasta dinner in the evening before the competition is good, but at most just one aspect of carbo-loading.
  • Too much dietary fibre. To be able to eat a sufficient amount of carbohydrates, you have to avoid eating fibre and instead eat various foods that contain lots of carbohydrates, such as white bread, white rice, sugar, carbo-loader drinks, lemonades, sports drinks, jams, honey, etc.
  • Instead of water, you should drink sweetened drinks, sports drinks, fruit juices or carbo-loader drinks. It is almost impossible to eat enough carbohydrates in solid form (e.g. pasta).
  • Fear of weight gain. Carbo-loading actually leads to an increase in weight of around 1 to 2 kg. However, this additional weight is only temporary and consists of the additional glycogen and water, which is stored in the muscles (as glycogen).


Proper carbo-loading is beneficial and effective in endurance sports lasting 90 minutes or longer (competition). However, it needs to be well structured and planned to ensure the required amount of carbohydrates can be consumed and processed without causing gastrointestinal tract problems. A reduction in training is essential, otherwise the stores will be emptied again during training.