Life finds a way.

I know a vegan with like 6 kids who tries to lecture me for eating meat.

Also, “proven” is a minefield these days. There are so many agents with so many agendas conducting these so-called medical studies. It’s difficult to know what to trust. For example, for decades the sugar industry has been paying “scientists” to conduct dodgy studies into the effects of fat in your diet in an attempt to deflect from the true horrors of added sugar.