Whole grains are different from refined grains in that they contain all three parts of a grain kernel: the starchy endosperm, which provides carbohydrates, protein and some B vitamins and minerals; the germ, rich in healthy fats and vitamins; and the bran, a concentrated source of fiber, minerals and B vitamins. When we eat whole grains, the fiber and healthy fats slow digestion, resulting in smaller spikes and dips in blood sugar. Fiber can also reduce blood cholesterol levels, support a healthy gut and lower the risk of developing colorectal cancer, cardiovascular disease and Type 2 diabetes.