I agree steady also the type of fiber matters a whole lot in my opinion.
I dont buy the whole grains are good for you argument.
If you couldnt eat it as it is I would avoid it.
Rather stick to fruits, and vegetables that do not need to be cooked, is ok to but they dont need to be.
I doubt our hunter gathering friends were chewing on rice, beans, wheat, "real corn" not the fake modern version, as their teeth would have broken down, and gotten bean poisoning.
Most of these foods are relatively new to humans, we have adapted to eating them because of the technology of fire, being able to break them down and soften them.
But it has only been consuming for a few thousand years, I doubt we evolve that fast.
For now I'll let the birds and other animals enjoy them, and I'll enjoy the animals, among the other things I mentioned.