Sometimes a trip can last much longer than anticipated, and having extra food and an additional one litre of water per person can make the difference between an extended stay and a survival situation. Outdoor activities require energy, and having extra food can give us the boost we need to get out of an unplanned situation. Water is even more important, and is needed by the body even more than food. A loss of 10% of total body fluid will cause extensive disruption of bodily functions; a loss of 20% usually results in death. Under “normal” circumstances, a person can survive for only 3 minutes without air, 3 days without water, and 3 weeks without food.