It's a Minhag for so long it's equivalent to Din.
WHATTTT?? Who are you, R chaim kanievsky???
Yes. I recently discovered the internet. Pleased to meet you.
Maybe you should change your name to Menachem614 in honor of your newfound mitzvos...
http://www.dailyhalacha.com/m/halacha.aspx?id=509
IIRC the gemara records someone giving two portions of (different) meat. Discussion closed?
MB says drink is fine, not water or seltzer
Since you brought it up... well sort of...You can't make a brocha on water if you're not thirsty because water has no taste. The only hana'ah is from the quenching of thirst.Well...what about seltzer? I remember in yeshiva, we had a big fight about this.