Total starvation includes complete deprivation of foods, salts and water. It results in death of the animal in the shortest possible time. Deprivation of water only follows death of the animal in approximately 7 to 10 days time, that of salts in two weeks time, whereas food starvation in 3 to 4 weeks or even longer depending on the reserve of fats in the body. The length of time, a man can survive, depends upon his fat stores, but the longest period of survival never exceeds 9 to 10 weeks.
Starvation induces a number of metabolic changes, some occurring within a few days and others occurring late. In addition to metabolic changes, a progressive fall in BMR occurs but pulse rate and blood pressure are affected much later. Ketosis develops and some retention of salt and water occurs and in prolonged starvation fatty liver develops.
Effects of food starvation
The effects of food starvation have been mostly observed in animals. But some direct observations have been carried out on volunteers and on professional fasting men.
• During the first few days, there is a craving for foods, particularly at meal times. But later on, this craving subsides, provided water and salts are freely allowed. Gradually, desire for food vanishes.
• “Weakness” gradually increases and a strong dislike to undertake any physical or mental effort develops. At about this time the subject falls into a state of semi-consciousness.
• The pulse rate and body temperature remain almost normal till before death, these are affected very late. The sleep increases and respiration becomes slower. Temperature falls before death.
• The amount of urine as well as its urea content falls
• The body weight is steadily lost. The daily loss in man during the first 10 days, amounts to between 1 to 1.5 per cent of the original body weight. At the onset of the fast, after depletion of glycogen stores, the fat depots and subcutaneous tissues bear the brunt. The extracellular fluid in large quantities is also lost.
• Dissolution of the muscular tissues and protoplasmic structures occurs much later. The muscle fibres are much reduced in size and many of the fibres are degenerated.
• Organs and tissues of the body are not affected alike. The more vital organs lose the least weight, whereas the less vital ones lose the most.