Hiking equipment
According to Tom Brown, the basic plan for survival is in the order of shelter (including clothing), water, fire, and food. Cody Lundin writes about the "Rule of 3s"; this relates to human survival without basics: three minutes without air, three hours without shelter, three days without water, or three weeks without food.
Inedia
Inedia (Latin for "fasting") or breatharianism is the belief that it is possible for a person to live without consuming food. Breatharians claim that food, and in some cases water, are not necessary for survival, and that humans can be sustained solely by "prana", the vital life force in Hinduism. According to Ayurveda, sunlight is one of the main sources of "prana", and some practitioners believe that it is possible for a person to survive on sunlight alone. The terms "breatharianism" or "inedia" may also refer to this philosophy when it is practiced as a lifestyle in place of the usual diet.