Survival skills
A human being can survive an average of three to five days without the intake of water. The issues presented by the need for water dictate that unnecessary water loss by perspiration be avoided in survival situations. The need for water increases with exercise.
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.