My personal top choice is the Mainstay 2400 Emergency Food Ration. This product is ready to eat, has a 5-year shelf life and tastes decent. In fact, it tastes a bit like lemon shortbread, which I love. This one-pound brick of six cubes is recommended to provide two days of food for one person. Each 2.67-ounce cube is 400 calories, with added vitamins and minerals. You will need ample water to drink with the rations, because as tasty as they are, they're also bone dry.