Whole grain breed is much more expensive, and some of it just containing 20~30% of whole grain flour and lest white flour.
Is it more economical sense that just eat normal bread + soymilk or sth which have enough fiber in it?

I always propose this approach when someone ask my advice
Same as omega-3. You can not just say ' i will eat fish 3 time a week from not on' and succeed it.
Some omega -3 rich oil like flaxseed or perilla would be better alternative or just simply take supplement without bad smell.