Two things necessary for continued survival when living out of Nature's pantry are fat and vitamin C. There are but few small animals, birds and fish with enough body fat to provide for man's needs. The 'possum is one that does and was cherished in the diet of those who lived off the land. Sumac berries dried naturally in the sun are high in vitamin C and will keep the scurvy at bay. You can quench your craving for tart foods with Sumac, Sheep shire and many wild fruits and green plants.
While there are many things Nature provides that taste good when you eat them, they mostly are subsistence foods; you can survive eating them but the palate is not pleased. Some exceptions to this are the lowly Poke weed, sumac, 'possum and persimmons. There are many others that make up the best of the wild foods, but these are the best of the best!