4) The Chasam Sofer (Shu”t, siman 157)
establishes that a sick person who is permitted to eat on Tisha B’Av may not eat more than his medical needs require. If he needs one koseves, he may not eat a second.
The Shu”t Maharil Diskin (Kuntras Achron, s.k. 75) agrees with the above. He writes that if one is sick on a regular fast day, he doesn’t need to fast at all, however, on Tisha B’Av even if one is sick, he must fast, and he is only allowed to eat that which is strictly necessary.
R’ Moshe Sternbuch shlita (Shu”t Teshuvos V’Hanhagos 2:261) brings from the Brisker Rav not like the above. He writes that even on Tisha B’Av, if one is ill and fasting will be dangerous to his health, he doesn’t need to go to the doctor to be assessed if he can fast. Such a person is exempt from fasting, as Chazal never included such a person in the obligation of the Tisha B’Av fast.
R’ Moshe writes that he was once walking with the Brisker Rav a few days before Tisha B’Av when they came across a Jew suffering from diabetes who required daily insulin injections. They Brisker Rav turned to this Yid and told him: “Tisha B’Av is approaching, and you will not fast at all — Chazal’s decree does not apply to you.”
With this background we can address our original shailah: A person is sick and he must eat on Tisha B’Av. If he eats bread, he will need five koseivos throughout the day. If he eats meat, being that meat is more calorie-dense and nutritionally efficient, he will suffice with three. According to the Chasam Sofer that one should minimize food intake, should such a person specifically choose meat?
R’ Yitzchak Zilberstein (Chasukei Chemed, Yoma 73b) brings that the Brisker Rav is medayek from the Rambam (Hilchos Taanis) that the main prohibition to eat meat and drink wine is on erev Tisha B’Av during the seudas hamafsekes [the final meal before the fast] because at that moment one carries the status of mesoi mutal lefanav (one whose deceased lies before him). However, on Tisha B’Av itself this status does not apply, and eating meat or drinking wine is, min hadin, actually permitted. According to this, certainly if eating meat saves two koseivos of food consumption, the sick person should certainly choose meat and eat only three koseivos rather than five.
However, R’ Elyashiv (Kovetz Teshuvos, siman 57) argues on the chiddush of the Brisker Rav and writes that from the Ohr Zarua we see that Tisha B’Av also has the status of mesoi mutal lefanav, and eating meat is prohibited min hadin. Therefore, the original doubt returns.
R’ Zilberstein then brings that his brother-in-law R’ Chaim Kanievsky zt”l leans towards prohibiting the consumption of meat, even if doing so will minimize the amount one is required to eat.
R’ Zilberstein then brings, that there may be a case where eating meat may be preferable even according to the stringent position. If the ill person would need either half a koseves of meat, or a full koseves of bread, then perhaps in such a case he should eat meat. The Biur Halachah (554, sif 6) establishes that the shiur for the issur of eating on Tisha B’Av is koseves hagasah (a large date-measure). Therefore, perhaps eating half a koseves of meat is better, as one who eats less than a koseves is still considered to be fasting.
