Certainly it is not for anthroposophy ever to assume a fanatical or a sectarian attitude. Its task is only to tell how things are. One simply cannot say that people should eat only plants, or that they should also eat animals, and so on. One can only say that some people with the forces they have from heredity are simply not strong enough to perform within their bodies all the work necessary to destroy plant fats, to destroy them so completely that then forces will develop in their bodies for producing their own fat. You see, a person who eats only plant fats — well, either he’s renounced the idea of becoming an imposing, portly fellow, or else he must have an awfully good digestive system, so healthy that it is easy for him to destroy the plant fats and in this way get forces to build his own fat. Most people are really unable to produce their own fat if they have only plant fats to destroy. When one eats animal fat in meat, that is not entirely destroyed. Plant fats don’t go out beyond the intestines, they are destroyed in the intestines. But the fat contained in meat does go beyond, it goes over into the human being. And the person may be weaker than if he were on a diet of just plant fats. [….]
But it is no use being fanatic about these things. There are people who simply cannot live if they don’t have meat. A person must consider carefully whether he really will be able to get on without it. If he does decide he can do without it and changes over from a meat to a vegetarian diet, he will feel stronger than he was before. That’s sometimes a difficulty, obviously: some people can’t bear the thought of living without meat. If, however, one does become a vegetarian, he feels stronger — because he is no longer obliged to deposit alien fat in his body; he makes his own fat, and this makes him feel stronger.
I know this from my own experience. I could not otherwise have endured the strenuous exertion of these last twenty-four years! I never could have traveled entire nights, for instance, and then given a lecture the next morning. For it is a fact, that if one is a vegetarian one carries out a certain activity within one that is spared the non-vegetarian, who has it done first by an animal. That’s the important difference.
Source: Rudolf Steiner – GA 354 – Nutrition and Health – Dornach, 31st July 1924
Translated by Gladys Hahn