If you've ever even thought about eating better or getting in shape, you were probably immediately bombarded from friends and websites with dubious advice about protein—so here is SciShow to quickly set the record straight. Nutrition is full of pseudoscience for a very simple reason: everyone eats, so everyone thinks they're an expert. So, here's what protein actually does.

The most common mistake people make is "muscle is protein, therefore the protein you eat gets added directly to your muscle." Wrong. The kinds of proteins muscles are made of have to be built from scratch inside your body. Protein you eat is broken down into amino acids, which are then rebuilt into stuff your cells can use. Your steak doesn't go to your biceps, because your steak is a cow, and your arms are not compatible with cow-muscle.