If one gulps down too much protein, it doesn’t go over into the body at all, but into the fecal waste matter. Even so, the body does get something from it: before it passes out, it lies there in the intestines and becomes poisonous and poisons the whole body. That’s what can happen from too much protein. And from this poisoning comes then very frequently arteriosclerosis-so that many people get arteriosclerosis too early, simply from stuffing themselves with too much protein.
It is important, as I have tried to show you, to know these things about nutrition. For most people are thoroughly convinced that the more they eat, the better they are nourished. Of course it is not true. One is often much better nourished if one eats less, because then one does not poison oneself.
Source: Rudolf Steiner – GA 354 – The Evolution of the Earth and Man and The Influence of the Stars – Lecture VI – Dornach, 31st July, 1924