Everyone loves a good feast from McDonald’s now and then. Sure, we all know eating fast food isn’t so great for our health, but we all do it anyway. Who can resist a chocolate milkshake, or value menu cheeseburger, or perhaps just a few fries?

I doubt anyone has ever had “just a few” fries, especially if those fries came from McDonald’s. Somehow that red cardboard box is always empty after a visit to the fast food chain.

McDonald’s fries seem to be in a category all on their own. No one else has quite managed to emulate the perfect thin-cut, slightly crispy fry with just the right amount of salt like they have. But did you know they used to taste totally different?

Back in 1990, McDonald’s had to change the way they made their famous fries. In fact, they used to taste way better! Those of us born prior to that date will never know the deliciousness of the original recipe.

Twenty-seven years ago, McDonald’s started using vegetable oil to cook their french fries. Prior to that date they used beef tallow, which is a rendered form of beef fat, and happens to be super tasty.

Malcolm Gladwell dedicated an entire episode of his podcast, Revisionist History, to the historical fast food moment. He reveals that the switch was made all because of one man named Phil Sokolov.

Sokolov was an American businessman who suffered a heart attack in 1966 at the age of 43. He had been a big fan of McDonald’s fries, but blamed the beef tallow they were cooked in for causing his poor health.