There's no good answer to this one, because we humans need a range of nutrients from a variety of foods to be healthy.
However, among the perfect survival foods would be beans, which pack protein and a load of other good stuff. If you could pick two things to eat, go for kale as a healthy leafy green next. It's particularly rich in vitamins, minerals and fiber, says our Bad Medicine Columnist Christopher Wanjek.
A long list of other worthy candidates would include fish, barley and berries. Oh, and in a pinch, you can go about 3 weeks without any food, though we don't recommend trying. Nor should you limit yourself to just a few foods.