From: Rabbi Moshe Sofer
To: Unknown recipient
Questions about whether one who eats on Erev Yom Kippur fulfills a positive commandment and how this interacts with other mitzvos of the day. The Chasam Sofer develops the concept that eating on Erev Yom Kippur is a form of 'innui' (affliction) by contrast.
Source: Shu"t Chasam Sofer OC §159