Importance of fat synthesis and storage : As is clear from above account, all surplus nutrients, digested and absorbed from above the immediate need of body, are readily converted to fat and stored, Normally about 200 times more energy is stored as fat than as glycogen ,Storge of fat for energy ( reserve food ) is very advantageous for following reasons:
1. It helps in maintaining normal concentrations of all mutrients in the blood.
2. While glycogen storage capacity liver muscles and other body cells is limited fat storage capacity of major adipose tissues is unlimited,
3. Fats are concerntrated food reserves requiring less space for storage. Hence fat storage is economical.
4. Since fat contains more of hydrogen and less of oxygen a given weight of fat yield about 2.25 times more energy than that of carbohydrates or proteins.
Hormonal control of fat metabolism: Insulin hormone promotes fat storage, whereas contisol thyroxine epinephrine and growth hormone stimulate degradation of fats for energy production,
Obesity If blood in excess of the requirement of body is taken continuously .i.e. energy input or agin is continuously more than energy output or expenditure. Fat storage swells resulting into fattening of the body and increase in its weight. This is called obesity.
Atherosclerosis: It is a disease of arteries in which fatty lesions,,called atheromatous plaques, develop upon the inside of arterial wall by deposition of cholesterol connective tissue fibres and often calcium salts, This causes hardening of the arteries blocking of blood flow in these extensive damage to arterial wall, hemorrhage ,thrombosis heart attack and ultimate death. The main factor causing atherosclerosis is high blood concentration of cholesterol due to increased intake of saturated fat in diet. Diabetes mellitus, hypothyroidism, smoking and male sex hormones promote atherosclerosis. Most important preventive measure is to stop smoking and to eat a low fat diet containing unsaturated fats (vanaspati) with low cholesterol content and margarine ( a butter substitute made from vegetable fats.)