Study the Maya
The maya are a good study into this...
the Mayan poor, ate nearly a vegetarian diet and were considerably shorter and unhealthy, having reproductive problems, etc. as evidenced by their skeletal structure... the ruling class\wealthy, were much healthier, taller, stronger, and lived longer, as evidenced by their skeletal remains.
And this, while the poor also worked harder and thus got much more *exercise*... flies in the face of politically correct conventional thought.
BTW- Mayan medicine has some interesting sites on the web... this *medicine* was born out of the poor diets and digestive woes and health issues that the poor had to deal with.
In addition, every time one traces historical *disease*, the disease occurred primarily in cultures with an agricultural foundation and a grain (carbohydrate) dense diet. Of course resource mining and metal working in some cultures also contributed to *specific* diseases such as certain cancers, etc.
grz-