Food is to the body what fuel is to a motor vehicle. It provides energy, helps repair and rejuvenation and confers many other benefits. While excess of food and gluttony is not good, occasional fasting does the body a world of good, provided one undertakes it under medical supervision and follows some basic guidelines. Here's what some doctors have to say on how to go about it.
Does occasional fasting have any benefits?
Dr G. S. Sainani, Director, General Medicine Department, Jaslok Hospital and Research Centre, Mumbai: When one fasts, the digestive organs get rest and all body mechanisms are cleansed. While fasting, the natural process of toxin excretion continues, while influx of new toxins is reduced. The energy usually used for digestion is redirected to immune function and cell growth. Fasting helps you heal with greater speed, cleanses your liver, kidneys and colon, purifies your blood, helps you lose excess weight and water, flushes out toxins, clear the eyes and tongue and cleanses the breath.
Dr. Issac Mathai, Chairman, Managing and Medical Director, SOUKYA International Holistic Health Centre, Bengaluru: Fasting, even occasionally, helps in de-toxification. Through fasting we restrict digestive activity and so energy is utilised to cleanse different systems. Fasting improves metabolism sharpens the senses, calms the mind, helps lose weight, improves general immunity, improves concentration and mental clarity.
Dr. Kousalya Nathan, Age Management Consultant, Huma Hospitals, Chennai: Fasting, if understood and done under supervision, has tremendous benefits and impacts one at various planes; mental, emotional, physical and spiritual. Specifically it serves as an aid to effective detoxification, helps in repair and rejuvenation, offers rest to the gastro-intestinal system and promotes mobilisation of excess fat.
The crucial point to note is the difference between fasting and starvation. Research suggests there are major health benefits to calorie restriction. Among other things it slows down the aging process. According to the US National Academy of Sciences, other benefits include stress resistance, increased insulin sensitivity and increased lifespan.
Dr. Sanjiv Rao, Head, Department of Medicine, Manipal Hospital, Bengaluru: I am not aware of benefits conferred by occasional fasting. No benefits accrue from consuming calories in a liquid form rather than solid form.
What are the risks if the fast is continued for a long time?
Dr. Damanjit Singh Chadha, Head, Clinical Operations, Centre for Internal Medicine, Fortis C-DOC, Fortis Hospital Vasant Kunj, New Delhi: Glucose is the body's primary fuel source and is essential for the brain's functioning. When denied glucose for more than 4-8 hours, the body converts glycogen stored in the liver into a usable form of fuel and supplements it with small amounts of protein. This will last for up to 12 hours before the body turns to glycogen stored in muscles.
If glucose is still denied at this point, muscle wasting is prevented by temporarily switching to fat as the fuel source, meaning fat is converted into ketone. The body continues to use fat for as long as it is available.
If the fast is not broken, starvation occurs, as the body begins to use protein for fuel. Health complications associated with fast-induced starvation include electrolyte imbalances, thinning hair, cardiac arrhythmia and renal failure. Death can occur if fasting is pursued to the point of complete starvation.
Is fasting advisable for diabetics, elderly, children and pregnant women?
Dr. Damanjit Singh Chadha: Fasting can cause low blood sugar, which can be life threatening in diabetics. In pregnancy low sugar and lack of nutrients can harm the foetus. Children and elderly people run the risk of starvation. Hypothyroid patients should also avoid fasting as it induces a drop in thyroid hormones. People with pre-existing kidney and liver disease should not fast either.
Dr. G.S. Sainani: Diabetics may go into hypoglycaemia. Children and elderly people cannot withstand absolute fasts. They can have juice or miss one main meal a day. Patients with a previous history of gastro-oesophageal reflux disease (GERD), gastric or duodenal ulcer can suffer relapse. Some may feel giddy and suffer from lack of concentration.
Dr. Issac Mathai: Fasting done properly does not induce acidity. Even in cases of hyper acidity, if appropriate liquids are chosen it is safe.
What changes take place in the body?
Dr. Damanjit Singh Chadha: There can be side effects due to the range of physiological changes. These include headache, nausea, muscle aches, nutritional deficiencies, weakness and cramps due to deficit of minerals like sodium, potassium, magnesium, and phosphorus.
Blood pressure could drop leading to fainting spells. Uric acid levels may rise, causing severe attacks of gout or a uric acid kidney stone. Some people experience hormonal changes. Cardiac problems occur very easily as do deaths due to serious ventricular arrhythmias, usually during long water fasts.
How frequently can an absolutely healthy individual fast?
Dr. Issac Mathai: It varies depending on the type of fast and individual. A short fast can be done once a month. Long fasts can be undertaken once every few months. If it is a fruit fast or raw diet fast, it could be weekly or fortnightly.
Dr. Damanjit Singh Chadha: Once a week or 2-3 days a month. If one is determined and medically fit, then one week to 10 days fast every three months is very beneficial but it should not be a complete fast. A fruit diet is recommended.
Any precautions or dos and don'ts?
Dr. Damanjit Singh Chadha: Learn about the process, the various fasts and side effects. If you have a pre-existing health condition then find out if there are contraindications with fasting. A thorough medical check up should be done before and in between the fast. Undertake fasts only under medical supervision. Do not go for complete fast. Try to arrange your fast in a time period when you have low activity. When you resume eating, start very lightly and very gradually in exact relationship to the duration.
Dr. Issac Mathai: When done under medical guidance, fasting is discontinued after judging the signs of complete detoxification. If stopped mid-way, then there is a danger of impaired metabolism and over eating. One should certainly take enema during the fast every day. Take care not to over-exert and resort to minimal activity. Do not engage in argumentative and highly stimulating conversations. Eat and drink at the proper time and also drink at least 10 glasses of water every day to prevent dehydration.
What are the different types of fasts?
Dr Kousalya Nathan:
Short fast: one to three days
Intermittent Fast: Two days of fast followed by two days of restricted food (this can be done for months under supervision and by balancing nutrition)
Long fasts: More than a week
Absolute fast: Abstinence from all food and liquid usually for a defined period
Liquid fast: Only water, clear soups and fruit juices for a specified period
Mono diet fast: A specific food is chosen and had for a specified duration
Fruit fast: Only fresh seasonal fruits
Raw diet fast: Uncooked fruits, vegetables and sprouts
