Anna Hazare during his fast in New Delhi

Fasting is common in India. Hindus fast on certain days of the week, Jains after six in the evening, Muslims during the month of Ramadan and Christians during Lent. Politicians and activists have traditionally used it as a means to an end.

Some fasts involve total avoidance of all food and water. In some others, food is avoided at specific times of the day. Yet others restrict the type of food. Fasting is different from involuntary starvation due to famine or illness. Voluntary fasting isn’t advisable for people under 15, over 70, pregnant women, people involved in outdoor or heavy labour, and those suffering from illnesses. Some medicines dangerously accelerate the biochemical effects of fasting.

Any food that we eat is digested and broken down into its components — glucose, fatty acids and amino acids. Glucose is the body’s main source of energy and is required by all tissues. When the body is deprived of food, any excess glucose stored in the body is accessed and utilised to get energy. Once these stores are depleted, the body starts to break down fat and use it. This is around 7 per cent of the body weight of males and 10 per cent in females. When is used up, there is an intense craving for food. If this is still not enough, the muscles in the body start to get metabolised. The person develops a wasted and emaciated appearance.

Deprived of food and water, a healthy adult can survive about 10-12 days. With water, survival can extend to 50-60 days. Children and the elderly succumb more rapidly. Women and obese individuals (both sexes) are able to withstand starvation better as they have more body fat reserves. Extremes of temperature (heat or cold) accelerate the ill effects of starvation.

Stopping food and water abruptly causes changes of “acute starvation” in the body within 24 hours. Thirst and hunger pains set in. The mouth gets parched, the saliva thickens and the urine is high coloured and scanty. After 48 hours, the voice becomes feeble, the pulse weakens, the temperature drops and dehydration sets in. As the days pass by, the blood pressure and temperature drop, the hair and nails become brittle, the eyes sink and the pupils dilate. Constipation is usual, but diarrhoea may occur. The intellect can remain clear and unclouded, but delirium and convulsions may precede death.

The medical complications associated with prolonged fasting are electrolyte imbalances, cardiac arrhythmia and kidney failure. Death can occur if fasting is pursued to the point of complete starvation.

Some medical tests have to be done upon “fasting” or on an “empty stomach”. There is often ambiguity and confusion between these two terms. Medically, fasting usually means an overnight fast of eight to 12 hours. That’s because metabolic adjustments occur in the body during fasting. The normal values of the results of some tests like lipid profile and sugar tests are standardised for fasting conditions. “On an empty stomach” typically means three to five hours after a meal, when the meal has left the stomach and digestion is complete.

Extended, intermittent, regular fasting has been recommended from the ancient times to preserve health. Today we know fasting improves the blood lipid profile and reduces total cholesterol. Research done on human volunteers at the US National Institute on Aging suggests that fasting every alternate day offers major health benefits. The cumulative calorific restriction reduces the risk of cancer, cardiovascular diseases, diabetes, insulin resistance and immune disorders. It also actually slows the aging process, and seems to have the potential to increase the life span. People do tend to lose weight with alternate day fasting, but on the negative side they tend to be irritable on the fasting day. Also, repeated fasts can result in the body going into a “conserve mode” and the metabolism slowing down to conserve energy. There will be no weight loss despite repeated intermittent fasting.

It is possible to “starve in the midst of plenty”. This occurs in diabetics who are unable to utilise the food they eat. In some others, the food may be unhealthy (just fat and sugar) and lacking essential proteins, vitamins and minerals.

Teenagers may resort to excessive fasting to prevent obesity. This can result in mental changes and anorexia nervosa.

Dr Gita Mathai is a paediatrician with a family practice at Vellore. Questions on health issues may be emailed to her at yourhealthgm@yahoo.co.in