Dried berries and sunflower seeds.
I could eat endless salads with them, for every meal of the day! But they have more calories than the rest of the salad combined!
My MIL told me way back when, (When she would then give me the bag come spring) that her family literally lived on black walnuts they had gathered during the depression. It only took a small amount to get in all their necessary calories for the day. That and minimal produce they could grow during the dust bowl area kept them alive and healthy for years.
