All over we say that there are only 2 mitzvos asei that if you don't do them, one is Chayiv Kares- Korban Pesach and Bris Milah. Why isn't eating on Yom Kippur also because there's no lav not to eat but rather a bitul of the Mitzvas Asei of V'inisem?
Sholom Twerski, Phoenix, AZ
Dear Sholom,
Great question. The Rambam demonstrates [1] that really there is a negative commandment associated with fasting on Yom Kippur, and a portion of his argument is based on your very point.
I hope this helps.
Best wishes,
Yishai Rasowsky
Sources:
1. https://www.sefaria.org.il/Sefer_HaMitzvot%2C_Negative_Commandments.196.1?ven=Sefaria_Edition_2021,_Translated_by_Rabbi_Francis_Nataf.&lang=bi&with=all&lang2=en
Dear Sholom,
I would add that the main source to help address issue would be in Yoma 81a-b [2], which the Rambam codifies [3].
Best wishes,
Yishai
Sources:
2. https://www.sefaria.org.il/Yoma.81a.7?lang=bi&with=Rashi&lang2=en