Health Topics

Healthy Living

March 2012
Fasting Fundamentals
Ishi Khosla
The reason why individuals or groups of people take to fasting can be very varied. It may be observed in thanksgiving, to seek something from a deity, as a prayer, as a celebration, as a remembrance or even for a cause.

Fasting patterns vary vastly with traditions, religions and cultural practices. Almost all fasts seem to be based on the fact that fasting helps build self-discipline, purify the body and
establish some sort of connectivity with the inner conscious. It is also about the satisfaction and strength gained through austerity. Good health does not seem to be the obvious intent.

  • Traditional fasts are usually followed by feasts and there are wide variations in the way people observe and break their fasts. The definition of a fast is therefore very
  • In its true sense, diet during a fast must be restricted in calories. The health benefits of fasts depend on the way they are observed and broken.
  • In general, breaking a fast is more critical than the fast itself. Breaking a fast should be done very slowly. Start with water, fluids and soft foods taken at short intervals and build-up the quantity gradually. This allows the body to recover its normal
    digestive capacity.
How does fasting affect the body?
  • The changes that occur in the body in response to a fast depend on the length of the fast.
  • Technically, one’s body enters the fasting state eight hours or so after the last meal, when the gut finishes absorbing the nutrients from the food.
  • In the normal state, body glucose, which is stored in the liver and muscles, is the body’s main source of energy. During a fast, this store of glucose is used up first to provide energy. Later in the fast, once the stores of glucose run out, fat becomes the next store source of energy for the body. Small quantities of glucose are also ‘manufactured’ through other mechanisms in the liver.
Do NOT starve yourself!
Only prolonged fasting (many days to weeks) causes the body to eventually turn to protein for energy. This is the technical description of what is commonly known as ‘starvation’, and it is clearly unhealthy.
  • Prolonged fasting must not be done to reduce body weight. Food deprivation also leads to a tendency to overeat or binge once food becomes available. The effect seems to last beyond a point when weight is restored to normal, sometimes for
  • People with eating disorders often report that fasting or a severely restricted diet heralded the beginning of their loss of control over eating. This indictment applies to extreme dieting and fasting but not to the moderate weight management strategies.
  • Fasting is not the best ways to lose weight. While the body’s lean tissue continues to be degraded, tissues are deprived of nutrients.
  • The body also slows its metabolism to conserve energy - wrong effect for weight loss.
  • A diet that moderately restricts calories promotes a faster rate of fat loss and the retention of more lean tissue (muscle and bone) than a severely restricted fast or a very low calorie diet. If at all fasting, it must be medically monitored.
Long-term fasting
  • Can have serious effects on the body -- weight loss, diarrhoea, vomiting,
    stomach pain, acid in the blood and urine, kidney overload, dehydration,
    increased heartbeat and low blood pressure, rapid breathing, change in
  • Some of the symptoms can be delayed if one takes salts and fruit juices periodically during the fast and maintains a 400-600 calorie intake.

Short-term fasting
  • Body tolerates better t Upsets the acid base balance of the blood and promotes excessive mineral loss through the urine. t In as little as 24 hours of fasting, the intestinal lining begins to lose its integrity.
  • Under normal conditions, the brain and the nervous system devour glucose –
    400 to 600 calories worth each day.
  • After about 10 days of fasting, the brain and nervous system can meet most of their energy needs using these ketone bodies.
  • Thus, indirectly, the nervous system begins to feed on the body’s fat stores.
  • Ketosis reduces the nervous system’s need for glucose, spares the muscle and other lean tissue from being quickly devoured and prolongs the starving
    person’s life.
  • Thanks to ketosis, a healthy person starting with average body fat content can live totally deprived of food for as long as 6 - 8 weeks.

Benefits of fasting
  • Fasting, in general, is believed to help inculcate discipline at physical, mental and spiritual levels and improve general health.
  • Some recent scientific studies report that fasting on alternate days and caloric restriction improves insulin resistance, lowers blood sugar levels, blood pressure and cancer cell proliferation.
  • A recent study in California (2007) reported that alternate day fasting may effectively modulate several risk factors, thereby preventing chronic diseases.
A sensible fast for health and well-being should include plenty of vegetables, fruits and fluids, and modest amounts of dairy, nuts, seeds and sprouts for the body to function effectively.

CAUTION: Fasting must not be undertaken by the chronically ill, under-nourished, pregnant and lactating women, and those suffering from serious illnesses. Those on long-term medication must consult with their physicians.
Ishi Khosla is Clinical Nutritionist and Director Whole Foods India New Delhi
  • The information on this site does not constitute medical advice and is not intended to be a substitute for medical care provided by a physician.
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