You have to unpack what "plant based" means. Food weight? Almost certainly. Majority of digestible calories? Doubt it. And there is no evidence a meat heavy diet is bad for us. Epistemological association studies. Give me cohort of high meat eaters who arent eating French fries and soda but are also eating fruits, vegetables, lowish starch and no/low sugar and I bet in an rct they'd be healthier than vegans. Meat is selection effects for fast food. It would make zero sense if meat was bad for us as we are human because of meat.