Why do people put oil/butter in pan when frying ground beef?

Question

I have always wondered why people put oil or butter in a pan before browning ground beef. It doesn't make sense since you end up having to drain the grease in the end anyways. What is the purpose of the oil or butter? Is it used for pans that are not non-stick? Flavor?

Answer

Transfer of heat. First you need a hot pan (sprinkle some drops of water on the pan, it should sizzle). Then you add a drop of oil and swirl it around. When the oil forms a striated pattern, it's hot. Then you put the meat in.

The hot oil helps to transfer heat from the bottom of the pan to the meat. You only need a spoonful of oil.

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