Beef usually gets a bad reputation for being unhealthy food. This is mostly thanks to its high content of cholesterol and the fact that it can cause heart diseases, but it remains one of the richest foods in iron, protein, and vitamins. Beef is especially rich in vitamins B6 and B12. In fact, meat whether from beef, fish or poultry remain the main source of vitamin B12, and unless you take vitamin B12 supplements, you are at risk of developing vitamin B12 deficiency if you are on a vegetarian diet. Beef also varies both in nutritional value and caloric content depending on its site. For example, a tenderloin has double the number of calories for the same weight as brisket.