Diet is largely a matter of fashion. It is very much influenced by completely unsuspected influences. In the Middle Ages, the healthiest food was considered to be that which was closest to God. That is, birds. Conversely, what grew underground was attributed to the devil. That's why peasants in Europe refused to grow potatoes for so long.

Today, something else is considered healthy. Who knows what will be considered healthy in 500 years.
!HUG
!HBITS