You can get fiber from a lot of places, it’s mainly that the claim of whole grains being part of a healthy diet is exaggerated. Technically your body doesn’t require grains at all, if you eat true vegetables you have fulfilled the purpose of grains in your diet. Notably, whole grains generally do not have a of micronutrients or even macronutrients. Compared to bleached white bread, which is whole grains with the exterior parts of the grain removed and then bleached and processed, you do get some additional nutritional benefits.

Whole grains are much easier for farms to produce because they already make up a large portion of the feed diet for livestock.