You might be surprised to know that there are a lot of myths out there about Five Guys burgers. Some people think they are vegetarian, or made from soy or tofu. Others think they are made with real cow meat. Some people are under the impression that Five Guys burgers are made from a combination of real beef and soy protein. The truth is that a Five Guys burger is 100% real cow meat. It is fresh, never frozen, ground upchuck. It's not made from any soy products. There have been concerns about this because Five Guys use peanut oil to cook their burgers, which was determined by a study at George Washington University in 2011 to contain 0.8% soy protein. Five Guys claims that their peanut oil doesn't contain any soy protein but just in case, their food is cooked in a separate area from where they prepare the buns and fries so the burgers don't come into contact with it. There are some other interesting facts about Five Guys burgers. One thing is that they don't use ketchup or mustard, instead they use their special sauce. But more importantly, Five Guys burgers don't contain preservatives such as BHT and BHA. These chemicals keep foods tasting fresh and not damaged by heat or bacteria. The best way to find out if a Five Guys burger is what it claims to be is by eating it yourself.