The Roman Emperor Vitellius (15AD – 69AD) wolfed down three or four substantial meals a day. On his way out to assume the post of commander of the army of Upper Germany in 68AD he greeted passersby by asking them if they had had a good breakfast, and then did what?
Answer: Gave a great belch to show that he had breakfasted himself.
Source: Life and Leisure in Ancient Rome by J P V D Balsdon