Bais HaVaad on the Parsha, Parshas Mikeitz

The Law of Conservation of Mass

December 18, 2025

Excerpted and adapted from a shiur by Dayan Daniel Dombroff   

Then seven years of famine will arise after them and all the abundance in the land of Mitzrayim will be forgotten; the famine will ravage the land.

Bereishis 41:30

During times of plenty, may one reduce his food intake by choice in order to lose excess weight?

According to R’ Elazar Hakapar (Ta’anis 10b), a nazir is considered a chotei for refraining from wine, and the same is presumably true of other foods. The Shulchan Aruch HaRav indeed derives from there that one may not deprive or afflict himself, except for the purpose of spiritual growth and gaining control of his yeitzer hara. Indeed, Chazal note that Yosef’s brothers had not drunk wine for twenty years prior to drinking with him in Bereishis 43:34.

R’ Moshe Feinstein writes that dieting to improve one’s mental state, e.g., to gain confidence by improving one’s appearance, is permitted, just like undergoing surgery, because it is for his benefit.

The Radvaz discusses the propriety of refraining due to a chumra. He writes that if the chumra is extreme and not accepted by the mainstream, it might violate R’ Elazar Hakapar’s directive, because batlah dato (his opinion is negated by the mainstream opposition to it).