Ad Acorn: 75 % of some nations lived just on them! 850 grams have 3300 kcals (mostly fat) so you can live just on them. A mature oak (Quercus spp. as well as tanoak, Notholithocarpus densiflorus) can produce almost
1000 pounds of acorns in one growing season during normal weather conditions in a good year–which usually occurs every four to five years (Ortiz 1991). They are reliable source of carbohydrates, protein, 6 vitamins, 8 minerals, and 18 amino acids, acorns are more carbohydrate than protein, and functionally more like a grain than a nut.