Not sure about variety effect, but overall they had much healthier diet from certain perspective (fruits + vegetables + lean muscles/whatever part of animal). No processed sugars, preservatives and other slow-poison crap. I don't think the diet was complete and for sure some vitamins/nutrients were often missing (ie in winter).

Combine it with much higher activity and they would look like superman with regard to fitness to average human these days. At least those who survived those harsh conditions, infancy and various easy-to-cure-now ails like tooth infection or appendicitis.