Horrifying. Racism applied to food
According to current theories, indeed, meat-eating had a profound effect on race Commentators asserted that it was meat that had nourished white intellectual and linguistic development over the course of evolution and that it was reliance on meat that had given Britons, "nicknamed "beefeaters", Anglo-Saxon racial traits. In contrast, the "lower races" allegedly ate mostly vegetable diets, and some said vegetarianism itself accounted for their humble place in the racial pecking order. According to the rather confused logic surrounding these discussions, meat had made whites the superior race that they were, and in turn, their superior racial identity made meat their natural food: wheat and beef were "the natural diet of the white man in the temperate zone," and white Americans were supposedly "born" with a desire for meat.23 The association between meat-eating, whiteness, and power helps to explain the wartime vitriol toward vegetarianism. Even as the government urged its citizens to eat less meat, those who exalted the martial virtues went out of their way to link vegetarianism to inefficiency, effeminacy, and cowardice.
From Moral Food, Modern Food, a book on 1900-1930s food beliefs. It's extensively cited from primary source documents.