Skip to content

19-02-2021 - Reading time: 4 minutes

How many carbohydrates do I need during training?

Carbohydrates are the most important supplier of energy for an endurance athlete. How much do you need if you go for a run or a bike ride, for instance? Our specialists gladly explain it all to you.

No doubt you have heard of the term ‘carbohydrates’. But do you know what it means exactly? Carbohydrates are the umbrella term for sugars and starch. They are present in many common foods such as rice, pasta, bulgur, potatoes and cereals, like oatmeal and quinoa. Examples of products that contain no carbohydrates at all are meat, cheese, egg, fish and poultry.

Source of energy

The most important purpose of carbohydrates is supplying energy. Are you a busy bee? Then you need more carbohydrates than non-athletes. The higher your heart rate, intensity or speed, the more fuel from carbohydrates your body needs. The good thing about carbs is that they supply energy quickly. Much quicker than fats which need more oxygen before they have the energy available. With (intensive) exercise it is therefore important to look at the intake of carbohydrates.


Prior to an intensive training session or important competition you can eat (extra) carbohydrates, i.e stacking carbohydrates. But is not a case of ‘the more you eat, the better it is’. If your body is not used to it, a high intake can cause gastrointestinal problems.

The body is able to store a small amount of carbohydrates in the liver and muscles, in the form of glycogen. Depending on the fitness and the amount of carbs eaten, the stored amount is usually enough for one to one and a half hours of exercise. How long exactly depends on the intensity. Before you run out of reserves, you will have to refuel.

How many carbohydrates?

So the demand for carbs depends on different factors: intensity, length and fitness. If your level of fitness is lower, your body will use more carbohydrates for fuel compared to someone whose level of fitness is higher.

There are some basic rules of thumb for carbohydrate intake after the first hour to hour and a half of exercise. If you exercise for between one and two hours, it is advised to take 30 grams of carbohydrates per hour. For exercise between two and three hours, the amount is 60 grams and for longer 90 grams is recommended. Your body can’t absorb more (or much more) than 90 grams of carbs per hour. If you eat and drink significantly more then this can cause gastrointestinal complaints.

  • 1 Eurosport nutrition Energy Bar supplies around 32 grams of carbohydrates
  • 1 Eurosport nutrition Energy Gel supplies around 26 grams of carbohydrates

2:1-ratio between glucose and fructose

When choosing your sports nutrition, it is important to look at the 2:1-ratio between glucose and fructose. These are both sugars. Products with a 2:1-ratio contain twice as much glucose as fructose. That is important for a reason: when a product contains only glucose your body can convert a maximum of 60 grams of sugar to fuel per hour. Quality sports nutrition with this specific ratio can increase this to 90 grams or even more. How is this possible? The body has different transporters in the intestine for glucose and fructose, so it can process more fuel. How much exactly depends, among other things, on how well your gastrointestinal tract is trained.

  • The formulas of all Eurosport nutrition Energy Bars, Energy Gels and Isotonic Sports Drinks have the 2:1-ratio between glucose and fructose.

Calculation example

For example: you are riding a granfondo that will take you exactly five hours. When exercising for 5 hours it is recommended to take in 90 grams of carbohydrates per hour. This means a total of 450 grams of carbs. Assuming your body loses around 500 millilitres of fluids every hour (depending on temperature, humidity and intensity), Isotonic Sports Drink will provide 33 grams per sports bottle (500 ml). The total of five sports bottles: 165 grams of carbohydrates. This means you need to get another 285 grams from other products. For example, you can take 5 Energy Bars (160 grams) and 5 Energy Gels (130 grams).