What health benefits are there to eating whole grains?

I have been hearing for years, especially recently, that I must have plenty of whole grains to keep my metabolism up, maintain a healthy weight, and aid in digestive health. I have always just believed these things without giving it much thought. I eat only whole wheat bread, have plenty of oatmeal, brown rice, whole grain cereal, etc. but is it really helping my health?

The definition of a whole grain according to the Whole Grains Council is that it contains "all the essential parts and naturally-occurring nutrients of the entire grain seed in their original proportions." Their website lists health benefits to regularly putting whole grains in your diet. The main health benefits they summarized are the reduction of health disease risks such as stroke, type 2 diabetes, heart disease, asthma, and helps regulate blood pressure. We should be getting at least three servings of whole grains daily because they contain nutrients that are vital to our health: protein, fiber, iron, magnesium, B vitamins, and many others.

Source:
http://wholegrainscouncil.org/whole-grains-101