I am sure I am not the only one practicing this diet: I have only very occasionally eaten in the last two months, and I have not drunk anything.
I get my energy and mood from:
1) refill at the beginning of the game day
2) quoins in the ancestral lands (a major source) that I visit 1 to 3 times per game day
3) some high value quoins in the streets
4) meditation
5) emblems
6) icons
7) No-no powder (at the end of the game day)
Because of the maximum of 100 quoins per game day, I usually avoid quoins outside of the ancestral lands.