I am currently reading John Robbins' book called Healthy at 100, and he studied the Hunzas. Robbins says that much of their skills were to do with the soil. They did keep animals, but according to him:
"The Hunzans have minimal pastureland, which makes animal husbandry nearly impossible. So like the Vilcabambans and Abkhasians, they eat very little meat. On certain rare feast days they eat goat or sheep meat, and on other days they consume a fermented milk product made from goat or sheep milk. But according to Leaf, meat and dairy products together constitute only 1 percent of their total diet."