1.) Did most of the american public who stuffed themselves full of thanksgiving turkey, ham, and mashed potatoes objectively commmit mortal sins?
2.) Is it a mortal sin of gluttony to eat two really full plates of dinner and be very full afterwards for hours?
3.) Is it a mortal sin of gluttony to purposely stuff oneself during dinner because one did not have enough calories during lunch or dinner?
Father Alphonsus the redemptorist who gives missions for the SSPX told us that gluttony is almost always a venial sin.
Maybe something like bulimia, the old roman feasts, would be mortal sins.
We still need to avoid venial sins. I've been gluttonous throughout much of my life, and I think the solution is to cut down one's eating so that it's under one's control. An occasional feast is fine, so long as one doesn't gobble one's food like an animal, eat hugely excessive meals, many pieces of pie, oversized steaks, more than one large hamburger, a whole large pizza, that sort of thing.
Part of the problem with recognizing the evil of gluttony today is that food is plentiful, so the harm we do is mainly self-inflicted harm. It's not like olden times when rich fat people ate enormous meals while peasants ate porridge, peas and black bread and counted themselves lucky if they could eat enough to not be starving.