Translation - Portugalski-Engleski - quem tudo quer tudo perde

I really don't know if the English proverb renders properly the sense of the Portuguese one. The latter has a sense of "losing for too much greediness", while the former sounds more like "nobody can be specialist in a large amount of things at the same time".

I agree with Goncin. I think that "Grasp all, lose all" renders it well. Quite a common saying in Britain.