To use another analogy: someone said culture is like software and
biology-genes like the hardware of a computer. If you try to use software
that is not what the hardware was designed to use, you can get a distorted
view of the software, the hardware can't fully or accurately understand it.
Modern food is like software that does not fit the hardware and therefore
the food distorts the “health” of modern man, because our hardware was
designed for the foods of the Paleolithic age and not for the foods
developed in the Neolithic and beyond. Culture or software changes much
faster than the hardware-biology-genes, and natural selection eventually
decides through successful or unsuccessful breeding which cultural changes
will become part of the longer term genetic-hardware, and which will not.
This may help define evolution and diet.

Ken