“After years of trial and error Franz [Kafka] has at last found the only diet that suits him, the vegetarian one. For years he suffered from his stomach; now he is as healthy and as fit as I have ever known him. Then along come his parents, of course, and in the name of love try to force him back into eating meat and being ill—it is just the same with his sleeping habits. At last he has found what suits him best, he can sleep, can do his duty in that senseless office, and get on with his literary work. But then his parents… This really makes me bitter.”
Letter to Felice Bauer (22 November 1912), in Letters to Felice by Franz Kafka, translated by James Stern and Elizabeth Duckworth (New York: Shocken Books, 2016), p. 57 https://books.google.it/books?id=EwVSqTfHdEAC&pg=PA57.
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Max Brod 2
author, composer, and journalist 1884–1968Related quotes

Characters, ch. 9 (12); translation from R. C. Jebb and J. E. Sandys (trans.), The Characters of Theophrastus (London: Macmillan, 1909), p. 75.
“Poets, Critics, and Readers”, p. 109
No Other Book: Selected Essays (1999)

After visiting such Nazi strongholds as were found in Berchtesgaden and Kehlsteinhaus; Personal diary (1 August 1945); published in Prelude to Leadership (1995)
Pre-1960

Quoted by reporter Thomas Watkins for the Associated Press http://www.contracostatimes.com/nationandworld/ci_7045394.

To Leon Goldensohn, February 4, 1946, from "The Nuremberg Interviews" by Leon Goldensohn, Robert Gellately - History - 2004.