Moderation and Self-Control

I shall speak first about control of the stomach, the opposite to
gluttony, and about how to fast and what and how much to eat. I
shall say nothing on my own account, but only what I have received
from the Holy Fathers. They have not given us only a single rule
for fasting or a single standard and measure for eating, because
not everyone has the same strength; age, illness or delicacy of
body create differences. But they have given us all a single goal:
to avoid over-eating and the filling of our bellies... A clear
rule for self-control handed down by the Fathers is this: stop
eating while still hungry and do not continue until you are
satisfied.

St. John Cassian