Depending where people evolved their diets are very different. People up in the extreme north only eat animals and fish most of the year without any veggies, grains, or fruits and were very healthy until grocery stores moved into the primitive life styles.
People who ate more veggies and grains and could avoid animal products because of warmer climate and longer growing seasons were very healthy, until grocery stores ...(fast foods with very little nutrients and very easy access to large quantities of food).
We have not evolved for fast chemical laden foods and easy access to large portions of food all day long!