Asker Jeukendrup is a professor of nutritional sciences and has worked for FC Barcelona, PSV, Jumbo cycling team, and the NOC-NSF, among others. His down-to-earth view of nutrition and performance is enlightening. We discussed nutrition for endurance and strength sports, HIIT training and the role of fats, carbohydrates, proteins and caffeine.


Simply put, what is healthy nutrition? 

You start with your energy needs. Simply put, you should not eat more than you burn or you will gain weight. It happens that people do very extreme diets and really eat too little, but that is not sustainable. The question is: do you gain anything if it doesn't benefit you in the long run? That is the problem with many diets. You have to look for something that is not extreme but easy to maintain. Start by looking at what you are eating and determine the products with the highest calories. What things can you replace with healthier foods and can you keep that up? When do you eat and how much are you eating and why? You need to understand that better, and sometimes you need some help from a dietitian.


What nutrition do you use during endurance exercise? 

Your body can only absorb 60 grams of carbohydrates per hour, so taking more than that makes little sense. The more intense the effort becomes the more important carbohydrates become. The problem is that the supply of carbohydrates runs out quickly, after 90 minutes you are usually depleted. You do want to have carbohydrates left in the finale of your race at longer distances. Therefore, you want to utilize the fat burning early in the race. To do this, you need to do more than just long endurance efforts, but also train at intensity. Like high intensity interval training, for example, as contradictory as it sounds.


What if you want to get stronger and/or bigger? 

The combination of nutrition and training is crucial. Quality of nutrition is just as important, everyone pays attention to amount of protein. But in many cases, it's about protein of which you can't absorb more than 20-25 grams either. We eat relatively little protein during breakfast and in-between meals. It is important for muscle production that you get 20-25 grams of protein every 3 to 4 hours. You get this from dairy, meat, nuts or vegetable protein etc.


How does caffeine work and how do you absorb it? 

If you look back at all the studies from the 1970s onward, you can see serious effects of caffeine consumption. The way caffeine works and what effect it has on the brain, caffeine is a real stimulant. Also the reason why we take caffeine before an exam or when we want to wake up in the morning. There is another mechanism and that is at the muscle level. This does not work through the brain but directly through the muscles. The advantage of a gum is that it is absorbed at lightning speed. Normally caffeine takes as much as an hour to get into your bloodstream, but through chewing gum it happens in as little as 10 minutes.  



Elite sporters are always ahead of the rest of the world. If you look back at today 10 years from now, what will then (still) be applied to you're everyday activity?

""The progress of nutrition and its applications in the future is that nutrition is going to be adapted to your daily needs. Nutritional needs are different on a day when you are active, doing strength training or inactive. In the cycling team this year, we worked with all the equipment on the bike, that are like modern laboratories. For example, we tune the food to the measured energy the riders consume in a stage.""  The technology to measure this is becoming more and more accurate and therefore more useful.

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1 comment

Het is een heel fijn product en gebruik het met veel plezier. Het geeft mijn s ochtends een boost.

Joey Timmers

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