You might have noticed that somehow most relevant Dutch fighters are heavyweights. The Dutch have been described by the Romans as giants. The Dutch have formed the elite guard of the pope in the middle ages and the Dutch have the longest average height in the world. All in all, the Netherlands house a lot of huge fighters like Overeem, Schilt, Struve etc.
Why?
the answer is genetics, customs and nutrition.
Genetics is a thing that one cannot change. It is just there. The Dutch have evolved on flat, open lands and therefore being tall meant a better view. Just like the Masai in Kenya who live in open spaces. On the other hand, races that live on mountains tend to be stocky and small (like the French).
Riding a bike is the second thing. In Holland, no matter if you own a Rolls Royce, once in a while you grab the bike, and using a car for short distances is frowned upon. Children don't ride the bus to school, they take the bike. This way being active and sportive is embedded in Dutch culture.
Nutrition is the third and maybe most important part. In Holland the traditional meal consists of potatoes, vegetables and meat. We eat that shit every day. It is almost like a bodybuilder diet, the reason why there are not as much obese people in Holland.
Concerning nutrition, one of the key factors in our physical build is the tradition of weekly eating "hamburgers". This is a typical Dutch dish named after the city Hamburg when it was conquered bij Dutch King Willem III in 1756. It basically is a bun cut in half, salad, some baked horsemeat, onions, pickles, salmon and mayonaise.
It is a Dutch tradition to eat hamburgers every saturday to remember king Willem III. The horse meat is very important for muscle growth. I've noticed that most Americans find it weird to eat horse, which amazed me. Eating cow and chicken can never fuel the muscle like a horse does.
Well that is basically what makes the Dutch the Dutch. As always: excuses me if i made any grammar errors, English is not my native language.
Thank you very much.