McDonalds used to fry their fries in beef fat. That used to be an industry secret until a lawsuit that was filed in India that disclosed they were using the fat of their sacred animals (McD's wouldn't serve beef patties because of their culture, but forgot about the fries).

After the lawsuit, health critics forced McD's to stop using beef fat to fry the fries in. Now they taste like crap like every other fast food restaurant.