I am guessing that what you are really worried about is avoiding manufactured or fabricated 'food-product', so if the question is whether or not oat bran is a healthy, fairly natural, less-processed food-stuff, the answer is yes. Don't be taken in by meme buzz-words as often as not the bear out to be conceptually senseless. Bran is a product of the milling process. It is the husk of an oat grain. Removing the husk of a grain (hulling) is a process, as are grinding, milling, cracking, rolling, baking, boiling, etc. The only truly unprocessed food is the raw element straight from the source. Meaning all flours, rolled oats, steel cut, cracked wheat, bulgar, farro, rice, ect. ect. as found in the market are processed foods. It would be exceedingly difficult to get any grains into your diet were you to swear off processed foods altogether. Milling is an ancient art traditionally practiced with wind, water, or animal power. It does not have leave a heavy footprint. If you have the wherewithal do support a reputable miller dedicated to treading lightly.