Beans are an awesome food. They are high in fiber and protein, and low in fat. They are also ridiculously cheap and very diverse in regards to their culinary role.
So, why are beans so fabulous?
Well, as I mentioned: they are high in fiber, particularily soluble fiber, which means they help to absorb, and then eliminate cholesterol in your body. Thus, lowering your cholesterol and improving you heart health. Also, fiber makes foods more filling, so high fiber foods, like beans, keep you feeling fuller longer, so you are less likely to overeat later on.
Beans, being a plant based food, also contain lots of good phytochemicals and isoflavins, which are basically components of food that are not ESSENTIAL to life, but certainly improve ones health. Different kinds of beans are higher in certain isoflavins and phytochemicals than others, so like all foods, eat a variety! Phytoestrogens in soybeans are probably the most well studied, and have been shown to decrease risk of cancer. (lots of research also shows that eating foods simply made with soy components may not have the same benefit, so as usual, I support eating the whole food or lesser processed versions.- edamame, tofu versus soy protein isolate.)
Beans are also a great source of folate. Folate (aka folic acid, B9) is a nutrient that extremely important to DNA and cell growth and division. This is most noteable during fetal development. If a mother is folate deficient, the baby will be born with neural tube defects which generally result in death to the fetus, or severely mentally and physically disabled. In the Western world, most refined grains are fortified with folate, if you are watching your whole grain intake, you are probably eating a lot of unfortified foods, so watch out for your folate intake by increasing your bean consumption! (leafy greens are also a good source of folate as well.)
So go forth, and get down with your beany self.