This isn't limited solely to vegetarians/vegans. Any diet that goes against your social group is difficult. Take keto/low-carb diets. It's amazing how snacks and foods I've been offered from friends and family that are just pure sugar.
I think that's true, but the same statistics of people on diet can be found, and I think (without any statistics of my own) that culture and group mentality plays a role there as well.
