Then there are ‘medical vegans’ I went to university with a guy who is one of those supersensitive to any form of animal fat and had a quad bypass at some seriously young age. To this day, he eats the strictest totally vegan and incredibly low fat diet. Without knowing his exact diet diary, I woud have to say that if he gets a total of more than 1 tablespoon of assorted added fat in his daily meals I would be amazed. His wife and kid eat whatever they want in addition to his cooking his meals, and I have seen his kid eat the occasional burger or ice cream.
I will say that within the parameters of his required diet, he is an incredible cook=)