There seems to be a LOT of confusion about the reason that we refrain from meat and wine during the week of Tisha B’av or, more commonly, during the ‘nine days’. The common reason is that these foods are associated with ‘simcha’, and ‘mi-shenikhnas Av mema’atin be-simcha’ – we refrain from joy once the month of Av begins.
The second reason, which, to my mind, makes a lot more sense, is to commemorate the destruction of the Temple, when animal sacrifice and libations ceased. Both of these reasons are alluded to in the halakhic literature (see, for example, Beit Yosef Orach Chaim 551:10.
As I’ve noted before, the famous Talmudic dictum ‘ein simcha ela be-basar ve-yayin’ (there’s no joy without meat and wine) DOESN’T EXIST. It is a paraphrase, and arguably a poor paraphrase, of a longer Talmudic statement. A non-existent Talmudic statement doesn’t seem to be a likely source for this custom. The IS a Talmudic account of those who stopped eating meat and drinking wine after the destruction of the Temple, to commemorate the loss of the sacrifices and libations, until R’ Yehoshua rebuked them that there’s no limit to that impulse, and that life must go on.
Furthermore, refraining from meat and wine has no other application. Mourners may eat meat and drink wine, even though most other customs of the ‘three weeks’ and ‘nine days’ have their parallels in the Laws of Mourning.
A potential ramification between the two reasons, as the title indicates, is eating fancy milechig meals during the nine days. If it’s about feeling the loss of korbanot, then it still does the trick. If it’s about excessive joy, then if eggplant parmesan floats your boat, then cross it off the Av menu. Of course, one can maintain (as the Kol Bo cited in the Beit Yosef) that even if it’s about joy, as long as there’s some form of discomfort, the mission is accomplished. That sort of begs the question, though; why would meat and wine specifically be the method by which we torment ourselves?
Personally, I find the korbanot rationale to be much more satisfying than the other. This period, to my mind, is about experiencing loss. It’s like a temporal zecher le-churban spot, in which this pervasive sense that things are out-of-whack creeps up on us (though, a friend of the ADDeRebbetzin said, “I don’t get depressed not doing laundry for a week; I get depressed the day after, looking at the accumulated pile!”), and the normal routine of things is intruded upon by this sense that something is amiss. That can be accomplished even while enjoying a nice fettuccini Alfredo.