Does In and Out Burger use MSG?
Similarly, you may ask, what kind of meat does in n out use?
According to In-N-Out's official website, the beef is "100% USDA ground chuck—free of additives, fillers and preservatives." To give you some perspective, not all fast food places can truthfully make this designation about their burger meat.
Just so, wHY DOES IN N OUT ask if you want onions?
Onions are polarizing. Customers rarely check what actually come on a sandwich/burger, and get mad when there are onions on it when they didn't expect them. Onions are not something you can just take off and not leave a taste, so they demand another burger. It's easier to just ask. this is why.
The most obvious thing that sets In-N-Out apart from its competitors is the scant menu, which ostensibly features nothing but burgers and cheeseburgers, plus fries, shakes and soft drinks. The very basic, thin fast-food patties housed in generic buns are nearly identical to those at McDonald's or Burger King.