Knowledge

By Christian Bitz, MSc in Human Nutrition

Now you are perfectly prepared and the depots are filled. But how much and how often should you eat on the trip? The body’s carbohydrate stores are limited to approximately 2000 kcal (=500g carbohydrate), which is only enough for a maximum of 1.5 hours of intense cycling, so it is important to replenish when you exercise for more than 1 hour. Overall, you burn approximately 800-1000 kcal/hour during intense training. This corresponds to 200-250 g of carbohydrates/h, which cannot be consumed without getting a stomach ache.
The maximum that can – and should – be consumed is 80-100 g of carbohydrates/h. Here are four examples of what you can consume per hour:

• 3-4 gels and water
• 1 gel, 1 bar, 500 ml water with 50 g. energy
• 1 banana, 2 gels, water
• 1 l water with 80-100 g energy drink

It is worth noting that some of the most skilled professional cyclists have developed an ability to consume up to 140 g of carbohydrates/hour, which is tremendous. Of course, it can push the boundaries of going sugar-cold, but it also requires a lot of training and getting used to.

Also remember that electrolytes (salts) are important – this is described after the After Training section.

By Christian Bitz, MSc in Human Nutrition

The body consists of 50-70% water and fluid balance is of great importance for performance. If you run really intensely in the heat, fluid loss through sweat can be more than 2 liters/hour. And when you sweat, minerals (also called salts and electrolytes) are also excreted. Sodium is the mineral that is most important for regulating fluid balance. Sodium is one part of sodium chloride, which everyone knows as common table salt.

There are large individual differences in how much we each sweat and how much sodium the body excretes. You can weigh yourself before and after a hard workout (where fluid intake is subtracted) to find out how many L/h you sweat. But it is not possible to determine the sodium content from a simple test. It can vary by about 0.5-1.3g sodium/L sweat. A good guess is therefore that we lose about 1 g sodium/L sweat. And this must be replaced equally with fluid. In other words, it is not enough to just drink water on long bike rides.

Using an electrolyte/salt mixture is therefore essential to regulate fluid balance. You should not drink more than you lose in sweat. BUT PLEASE NOTE:
The body can only absorb a maximum of 1-1.2 L of fluid per hour, so you should not drink more, even if your sweat loss is greater.

If you sweat more than you consume, you should drink fluids with electrolytes after exercise. You should do this continuously with 1.2-1.5 liters of fluid with 1 g of sodium/L for each kilogram lost during exercise.

Please note that most of us get some salt (and thus sodium) through the food we eat, so some of the fluid when you return may also be water. When foods, gels, etc. indicate the salt content, it is NOT the same as the sodium content, because table salt also contains chloride. Therefore, you should use the formula: sodium content = salt content x 0.4.