It is a low fat food, but very high in protein (which is why it is so important for vegetarian/ vegan diets- it replaces the meat) and it is a good source of fiber which helps you clean out your system by increasing fecal matter (which is why it is also helpful if you struggle with constipation/ irregular stool). It contains iron- an essential mineral. Iron deficiency, especially if you are a woman (iron is contained in blood- more precisely, in hemoglobin, which in turn is a component of Red Blood Cells, which women lose every month while menstruating), may lead to exhaustion, and not enough red blood cells that carry oxygen throughout the body which is what we call anemia. Despite having all these good things that help you maintain good health, in the end beans are most useful for its high protein content.