» The accumulation and utilization of fat
The accumulation and utilization of fat
The accumulation of fat or obese in any person occurs when energy intake exceeds its costs over time. Very minor, but constant excess energy leads to a marked accumulation of fat in the body. Thus, the use of only 5% of "extra" calories can contribute to the accumulation of about 5 kg of fat per year. If within 30 years the consumption exceeds the cost of just 8 calories per day, it can lead to an increase in body weight of 10 kg. These figures reflect the average weight gain during 30 years (from 25 to 55 years) adults.
Triglycerides are the primary fat reserve fuel in the body. In lean adults have up to 35 billion fat cells - the cells of adipose tissue containing 0.4-0.6 mg of triglycerides in people with severe obesity, adipocytes in 4 times (125 billion), and each contains twice as much fat (0.8-1.2 mg of triglycerides). High energy density and hydrophobic properties of triglycerides make them 5 times more fuel efficient per unit mass than glycogen. Triglycerides in the oxidation of release 9.3 kcal / g energy and packaged in the form of oil droplets in fat cells, making up 85% of the total mass of adipocytes. For comparison, the oxidation of glycogen (animal starch) is allocated only 4.1 kcal / g energy. Glycogen is located extracellularly in the form of gel containing approximately 2 g of water for every gram of glycogen.
Thus, adipose tissue represents a model of effective conservation of fuel cell and ensures the survival and the ability to move in the absence of food. In fact, life in conditions of hunger depends on the amount of adipose tissue in the body. The thin man dies after about 2 months of fasting, losing weight more than 35% (about 25 kg). At the same time, obese people are exposed to therapeutic fasting for over a year, had no significant adverse effects. There is evidence of a long and fast, when a man weighing 207 kg, is used not have contained liquid calories, vitamins and minerals for 382 days reduced their weight by 61% (126 kg).
The fundamental principle of treating obesity is to consume less than the costs, the amount of calories to gain use of endogenous energy stores as fat. During the diet of almost 75-85% of the weight lost as fat, and only 15-25% due to non-fat components. Although an energy deficit of 3,500 calories 450 g requires the oxidation of fat is actually an energy deficit of 3,500 calories can lead to loss of more than 450 g body weight, due to the oxidation of tissue containing no fat, and due to water loss. In addition, loss of body fat is uneven, depending on its distribution: for men and women with predominant accumulation of fat in the abdominal weight loss is largely due to a reduction in the number in this area.
In general decrease in the amount of adipose tissue caused by the reduction in size (due to the fatty component) of fat cells. It is also clear that weight loss in humans leads to a decrease in the number of fat cells. But perhaps a significant reduction in the size of adipocytes in patients with severe weight loss makes it impossible to detect them using standard techniques, so that might get the wrong impression about reducing the number of cells.
Reducing the number of fat cells at weight reduction could be possible due to conversion of the latter. Although the morphological and biochemical transformation of adipocytes was obtained in the experiment, there was no evidence of the existence of this process in the body.