Fasting is the abstention from, or deprivation of, food and drink. It may result from a genuine desire to lose weight – in an attempt to improve one’s health and/or appearance – or from a MENTAL ILLNESS such as DEPRESSION, or from one of the EATING DISORDERS. Certain religious customs and practices may demand periods of fasting. Forced fasting, often extended, has been used for many years as an eﬀective means of torture.
Without food and drink the body rapidly becomes thinner and lighter as it draws upon its stored energy reserves, initially mainly fat. Body temperature gradually falls, and muscle is progressively broken down as the body struggles to maintain its vital functions. Dehydration, leading to cardiovascular collapse, inevitably follows unless a basic amount of water is taken – particularly if the body’s ﬂuid output is high, such as may occur with excessive sweating.
After prolonged fasting the return to food should be gradual, with careful monitoring of blood-pressure levels and concentrations of serum ELECTROLYTES. Feeding should consist mainly of liquids and light foods at ﬁrst, with no heavy meals being taken for several days.