Coca, Silman told me, made a heavy pack feel lighter. It also staved off hunger, alleviated aches and pains, and helped counter altitude sickness. I had been given little to carry besides my own gear; still, anything that would lighten my pack seemed worth trying. I took a handful of leaves and a pinch of baking soda. (Baking soda, or some other alkaline substance, is necessary for coca to have its pharmaceutical effect.)
