Chapter 42: 4-6
The Laws Pertaining to a Meal
4. A person should not display anger when eating. This will cause guests and the members of his household to be embarrassed to eat, lest their host has become upset and angry at their eating.
5. A person should not talk during a meal, even words of Torah, lest he choke, the food going down the windpipe rather than the esophagus. It is even forbidden to wish a person who sneezes "good health."
[This applies only while actually eating.] While one is not eating, it is a mitzvah to recite words of Torah at the table, and one should take great care regarding this. After partaking of the bread over which hamotzi is recited, it is a proper custom to recite [Psalms 23]: Mizmor l'Dovid: Ado-noi Ro'i lo echsor ... ("A Psalm of David: G-d is my Shepherd, I shall not want..."). This is considered as both words of Torah and a prayer for one's sustenance.
On a weekday, after the meal is concluded, it is customary to recite [Psalms 137]: Al naharos Bovel... ("By the rivers of Babylon...). On the Sabbath, festivals, and any days on which tachanun is recited, we recited [Psalms 126]: Shir Hama'alos: b'shun Ado-noi - ("A Song of Ascents: When G-d returned...").
A person should take care when studying from a book at the table, because it is possible that small worms will be found in the bindings. [They might fall into his food] and he may eat them and transgress a prohibition, Heaven forbid.
6. When a number of people sit down to eat together, it is proper to wait and allow the person of greatest stature to begin eating first. This applies even if each person was given his own separate plate or serving of fruit. A person who begins eating before a person of greater stature is considered a glutton.