A combination of a lower requirement for energy and careful use of what fuels are available (including some recycling, for example of red blood cells) allows fasting to continue for many weeks before any vital tissues become threatened (unless at the starting point the faster is already emaciated or malnourished). The longer the fast continues the more efficient the body function in reducing its dependence on glucose and the more efficiently it uses fatty tissues for its reduced energy requirements.⁶ Changes seen on a fast
A wide array of biochemical changes occur during fasting, some of them unpredictable, being dependent on your state of health at the outset. Many, however, are predictable, including hormonal changes of particular significance to longevity.⁷ Except in very overweight people, one of the key changes seen is an increase in the production by the pituitary gland of Growth Hormone (GH), of which much more will be heard in our continued exploration of life extension mechanics.

From the viewpoint of enhanced health there are the many beneficial changes which take place in immune function during fasting.⁸ Most of these improvements, notably affecting immune function, carry on into the period after the fast. This is perhaps the most important aspect of fasting for better health.

What fasting can achieve
Among the conditions successfully dealt with by fasting alone are the following: diabetes,⁹ gangrene,⁹epilepsy,^10,11obesity (although this condition requires counselling and lifestyle modification for continued benefit),¹²heart disease,^13,14,15pancreatitis,¹⁶poisoning with toxic chemicals (dramatic benefits with seven to ten day fasts),¹⁷autoimmune disease such as glomerulonephritis, ¹⁸ rheumatoid arthritis,^19,20,21 (a 1984 study in the US²² showed remarkable improvement after seven-day fasts), food allergy,²³ psoriasis, varicose ulcers, bronchial asthma, schizophrenia and many more (references to these are given by Salloum and Burton, reference 6 below).

Recent proof from Norwegian research
A one year study of people with rheumatoid arthritis was carried out in Norway. The researchers stated that while fasting is proven as an effective treatment for rheumatoid arthritis, many patients relapse when they start eating again. In this study they followed the four week semi-fast with a one year vegetarian diet, and it was found that all the benefits of the fast (marked reduction in number and intensity of swollen joints, pain and stiffness; increased strength; improved blood chemistry and overall health status) were maintained at the end of the year. The fast itself was not total but included herbal teas, vegetable broth and vegetable juices (no fruit juices because of sugar content). The calorie intake during the fast ranged between 800 and 1,250 per day. When eating was resumed the participants were, for the first three to five months, asked to avoid meat, fish, eggs, dairy produce, refined sugar, food containing gluten (e.g. wheat), citrus fruits, strong spices, tea, coffee, alcohol and preservatives. After this they were allowed dairy produce and gluten-containing foods, unless there was any reaction to them (swollen joints or pain etc.) in which case these foods were stopped again.