As soon as you secure both shelter and a water source, the pressure for survival shifts to food. This is the long game. In extended emergencies, the daily quest for food can quickly become your all-consuming task. Foraging, fishing, trapping and hunting can be fulfilling activities, and give you a full belly if you're lucky. In a multi-day ordeal, you'll probably spend most of your time looking for food (that is, when you're not signaling for help). In the right season and location, wild plants might give you all the protein, fat and carbs you'd need. Using a book like Peterson's Field Guide to Wild Edible Plants can help you to safely identify and prepare tree nuts, seeds, roots and many other edible plant parts. And if you don't have that book and you're not sure about your local wild edible plants, then stick with animal foods. Fish, worms, crickets and many other critters are safe for human consumption. Just make sure that you cook them thoroughly, as many of them are loaded with parasites or disease causing pathogens. Try to focus on calorie-dense foods, like fatty animals, tree nuts, bone marrow, and organ meats. At the end of the day, survival is about calories, so I hope you're not picky! Get enough calories to stay strong, and avoid calorie loss through hypothermia and dysentery.