Thomas Costain's history, The Three Edwards, described the life of Raynald Ill, a fourteenth-century duke in what is now Belgium. Grossly overweight, Raynald was commonly called by his Latin nickname, Crassus, which means "fat."
After a violent quarrel, Raynald's younger brother Edward led a successful revolt against him. Edward captured Raynald but did not kill him. Instead, he built a room around Raynald in the Nieuwkerk castle and promised him he could regain his title and property as soon as he was able to leave the room.
This would not have been difficult for most people since the room had several windows and a door of near-normal size, and none was locked or barred. The problem was Raynald's size. To regain his freedom, he needed to lose weight. But Edward knew his older brother, and each day he sent a variety of delicious foods. Instead of dieting his way out of prison, Raynald grew fatter.
When Duke Edward was accused of cruelty, he had a ready answer: "My brother is not a prisoner. He may leave when he so wills." Raynald stayed in that room for ten years and wasn't released until after Edward died in battle. By then his health was so ruined he died within a year. . . a prisoner of his own appetite.