Not many people do, that's why they eat margarine instead of butter. There was a huge push (that's still ongoing) against fats, and everything is labelled "fat-free" where instead they just fill it full of sugar, but the damage is done, and people avoid animal fats in general if they're trying to be "healthy". At the end of the day, you have to do your own research. Understand that a lot of stuff comes from paid research that it meant to push a product rather than in the interests of science and truth. Also, different people can and will respond in different ways depending on age, race, sex, etc. The only way to know for sure is getting a blood test done, doing your diet for a while, retesting, and comparing the results. Anything else is just guess work.