The Tisha B'Av Diet

תנו רבנן כשחרב הבית בשניה רבו פרושין בישראל שלא לאכול בשר ושלא לשתות יין נטפל להן ר' יהושע אמר להן בני מפני מה אי אתם אוכלין בשר ואין אתם שותין יין אמרו לו נאכל בשר שממנו מקריבין על גבי מזבח ועכשיו בטל נשתה יין שמנסכין על גבי המזבח ועכשיו בטל

Bava Batra 60b:11

...The Sages taught in a baraita (Tosefta, Sota 15:11): When the Temple was destroyed a second time, there was an increase in the number of ascetics among the Jews, whose practice was to not eat meat and to not drink wine. Rabbi Yehoshua joined them to discuss their practice. He said to them: My children, for what reason do you not eat meat and do you not drink wine? They said to him: Shall we eat meat, from which offerings are sacrificed upon the altar, and now the altar has ceased to exist? Shall we drink wine, which is poured as a libation upon the altar, and now the altar has ceased to exist?

בבא בתרא ס׳ ב:י״ב

אמר להם א"כ לחם לא נאכל שכבר בטלו מנחות אפשר בפירות פירות לא נאכל שכבר בטלו בכורים אפשר בפירות אחרים מים לא נשתה שכבר בטל ניסוך המים שתקו

Bava Batra 60b:12

Rabbi Yehoshua said to them: If so, we will not eat bread either, since the meal-offerings that were offered upon the altar have ceased. They replied: You are correct. It is possible to subsist with produce. He said to them: We will not eat produce either, since the bringing of the first fruits have ceased. They replied: You are correct. We will no longer eat the produce of the seven species from which the first fruits were brought, as it is possible to subsist with other produce. He said to them: If so, we will not drink water, since the water libation has ceased. They were silent, as they realized that they could not survive without water.

בבא בתרא ס׳ ב:י״ג

אמר להן בני בואו ואומר לכם שלא להתאבל כל עיקר אי אפשר שכבר נגזרה גזרה ולהתאבל יותר מדאי אי אפשר שאין גוזרין גזירה על הצבור אא"כ רוב צבור יכולין לעמוד בה...

Bava Batra 60b:13

Rabbi Yehoshua said to them: My children, come, and I will tell you how we should act. To not mourn at all is impossible, as the decree was already issued and the Temple has been destroyed. But to mourn excessively as you are doing is also impossible, as the Sages do not issue a decree upon the public unless a majority of the public is able to abide by it...

Lyndall Miller