Biological Chemistry - Berezov T. T., Korovkin B. F. 1998

Lipid Metabolism
The Role of Lipids in Nutrition

Lipids are an essential component of a balanced human diet. On average, an adult human ingests 60–80 g of animal and plant fats daily with food. In older age, as well as under conditions of low physical activity, the requirement for fats decreases, whereas in cold climates and during heavy physical labor, it increases.

The Role of dietary fats is highly diverse. First and foremost, fats serve a crucial energetic function in Human Nutrition. Their caloric value is higher than that of Proteins and CARBOHYDRATES. It is well established that The oxidation of 1 g of fat yields 38.9 kJ (9.3 kcal), whereas the oxidation of 1 g of protein or carbohydrate yields only 17.2 kJ (4.1 kcal). In addition, fats act as Solvents for Vitamins A, D, E, and K; consequently, the body's supply of these vitamins largely depends on dietary fat intake. Fats also supply certain polyunsaturated Fatty acids (linoleic, linolenic, and arachidonic) classified as Essential Fatty Acids, since human and several animal Tissues have lost The ability to synthesize them. These acids are collectively referred to as "vitamin F."

It is also well known that fat enhances the palatability of food and is essential for food preparation and storage. As a result, fat consumption in highly developed countries is so high that it accounts for more than 35%, and in many countries over 40%, of total daily Energy Expenditure. In turn, this frequently leads to a high-fat intake that exceeds the body's physiological Energy Requirements, causing such adverse health issues as widespread obesity among a significant portion of the population. Therefore, understanding normal Lipid METABOLISM is crucial for comprehending the causes of numerous diseases. It is well documented that lipid metabolism disorders occur, for instance, due to excessive or inadequate fat intake, enzyme deficiencies, or hormonal imbalances, among other factors.