Bran is the outer layer of cereal grains. This layer is not processed and is a byproduct of the grains. In the past, this byproduct was discarded. It wasn't until the last 40 years that it was discovered to have beneficial qualities. Here is a nutrition guide to all bran cereal and why it's a good choice for you. Health Benefits. Bran is high in fiber and a good number of people use it for that benefit. It's also good for preventing heart problems, colon disorders and cancer. Fiber fills you up and keeps your body feeling fuller longer. Bran also has protein.