It often gets brought up that Hitler was a vegetarian and occasionally someone will go so far as to claim Hitler was a vegan (even though the term was only coined in 1944).
The issue itself isn't a particularly large one for vegans. Attempting to use Hitler's diet to make any point about vegetarianism is using the reductio ad Hitlerum logical falacy (really ignoratio elenchi). I've been told that Hitler didn't smoke either and this doesn't bother me in the least as a non-smoker.
Nonetheless, this is an interesting question relating to veganism and skepticism. What was Hitler's diet like? Was Hitler in fact a vegetarian?
On May 30, 1937 the New York Times published an article titled "Where Hitler Dreams and Plans", written by Otto D. Tolischus. In the article Tolischus writes, "During breakfast, which usually consists of milk, bread, oatmeal, honey, and cheese, [Hitler] reads the newspapers, especially his own Voelkische Beobachter."
Hitler's diet certainly was not light on the animal products, but at least for breakfast it appears Hitler tended to stay vegetarian. Tolischus continues, "It is well known that Hitler is a vegetarian and does not drink or smoke. His lunch and dinner consist, therefore, for the most part of soup, eggs, vegetables and mineral water, although he occasionally relishes a slice of ham and relieves the tediousness of his diet with such delicacies as caviar, luscious fruits and similar tidbits."
Hitler certainly considered himself to be vegetarian, as is written here and is repeated by a number of other sources. At the time this article was published, his diet appears to have been low, but not absent of meat, and high in other animal products. He could most appropriately be described by today's language as a flexitarian.