The Deipnosophists (2.41)

Nicander mentions also nuts of Pontus, which some writers call λόπιμα; while Hermonax and Timachidas, in the Dictionary, say that the acorn of Jupiter, or walnut, is what is called the nut of Pontus.

But Heraclides of Tarentum asks,

Whether sweetmeats ought to be put on the table before supper, as is done in some parts of Asia and Greece; or whether they ought to be brought on after supper is over.

If it is decided that they are to be brought on at the end of supper, then it follows, that when a great deal of food has already been put into the stomach and bowels, the nuts which are eaten afterwards as provocatives of drinking, get entangled with the rest of the food, and produce flatulence, and also cause what has been eaten to turn on the stomach, because it is followed by what is by nature unmanageable and indigestible; and it is from such food that indigestions and attacks of diarrhœa arise.