According to Femail First website Prince Charles eats only one meal a day. Can it be true?:

Prince Charles eats just one meal a day to stay slim. The royal dad-of-two told fitness guru Rosemary Conley that his lithe princely body is down to a strict diet of virtually nothing. Conley, who became famous for her fitness videos in the 80s, says she was so stunned by his reply she thought about inviting the prince and his wife Camilla round for a healthy dinner fit for a king. She revealed to Britain’s Now magazine: “I met Prince Charles. He was fantastic. He made me feel like the only person in the room. I said, ‘I work hard at trying to get the nation healthier and fitter and if they were all as active as you, they wouldn’t have a problem’. He laughed and said, ‘I can only keep my weight down by eating just one meal a day.’ I came away thinking, ‘Ooh. I’d really like to invite Charles and Camilla round for dinner.’ “

Clearly the Prince inherits few of the genes of Henry VIII.