Biochemical Foundations of Human Life Activity - Volkov, N.I., Nesen, E.N. 2000

Biochemical Foundations of Human Life Activity
Biochemistry of Lipids
Fat Metabolism in the Body

Fats enter the body through animal and plant-based foods. An adult requires from 70 to 145 g of fat per day (primarily in the form of triglycerides), including 15 g of Unsaturated Fatty acids and 10 g of Phospholipids. Daily fat requirements depend on gender, climatic conditions, physical activity, or nature of work.

The average fat content in an adult body is 7–8 kg for men and 5–6 kg for women, or 10–15% of total body weight. In cases of obesity, this figure can reach 30% of body weight or more. Fats provide 25–30% of a person's energy needs. Furthermore, animal fats supply Fat-soluble Vitamins A, D, E, and K, while vegetable oils provide unsaturated fatty acids (vitamin F), which serve as precursors to BIOLOGICALLY ACTIVE SUBSTANCES such as Prostaglandins, as well as the Starting Material for the Synthesis of phospholipids and Other Compounds.

Dietary fats entering the body undergo enzymatic breakdown in the gastrointestinal tract down to structural monomers—glycerol, fatty acids, and other constituents—which are then absorbed into the intestinal wall. Partial synthesis of triglycerides occurs directly within the intestinal mucosa. From there, the majority of Lipids enter the intestinal Lymphatic system, then into the Thoracic duct, and subsequently into the bloodstream. A certain portion of triglycerides is deposited in fat depots and the Liver. When the body requires energy, these undergo Hydrolysis followed by The oxidation of glycerol and fatty acids. The main Stages of Lipid METABOLISM in the Body are schematically presented in Fig. 69.