How do these people stay alive?

I'm sure you know someone like this. Perhaps you are one of these people. They never eat vegetables. They eat only junk. Burgers fries, etc. They never eat anything that isn't completely processed. It boggles my mind how they don't develop severe dietary deficiencies like scurvy or beriberi. Personally I'm an omnivore. I had a salad today that included spinach, 5 different kinds of peppers, avocado, tomato, 2 different cheeses, kippered herring, green and black olives and blue cheese dressing. My resident junk food eater thought it was "disgusting".