Yatu yamam gata-rasam puti

Yatu yamam gata-rasam puti paryusitam ca yat |
Ucchistamapi camedhyam bhojanam tamas priyam ||
                                                           -Gita XVII -10

Meaning: Stale, tasteless, decomposed, putrid and leftover foods are dear to a person of Tamsik nature. Jatayu's conversation with Ravana as scripted in the Ramayana also has some reference to the quality of food. Talking of moral principles, Jatayu says  "Eatable food is that which is completely digested in a natural way, without producing any harmful effect inside the body". Some scriptures also comment on the best quantity of food intakes. For example, the Vishnu Purana suggests

- Gita XVII -10