We are but the veriest, sorriest slaves of our stomach. – Jerome K. Jerome, Three Men in a Boat (To Say Nothing of the Dog), 1889
The best General Rule for Diet that I can write, is to Eat and Drink only of such Foods—at such times,—and in such quantities—as Experience has convinced you, agree with your Constitution—and absolutely to avoid all other. – William Kitchiner (1775–1827), “Art of Invigorating Life,” The Art of Invi

