Detailed Explanation of Lipid Functions and Overview of Key Nutrients: From Protecting Internal Organs to Macronutrient Deficiencies

The main physiological functions of fat include: protecting internal organs, maintaining body temperature, buffering, providing energy, and storing energy. Excess energy ingested by the body, regardless of its nutrient source, can be stored as fat. Adults typically have 10%–20% body fat, while obese individuals may have 30%–60%. Studies have found that in a fasting adult at rest, approximately 25% of their energy needs are met by free fatty acids, 15% by glucose, and the remainder by the breakdown of endogenous fat, indicating a significant proportion is stored fat. Dietary fat can enhance the flavor of food, stimulate appetite, increase satiety, slow gastric emptying, and aid in the absorption of fat-soluble vitamins and carotene. Brief Nutritional Information:

Protein. Main functions: It constitutes essential substances for body tissues; it forms enzymes, antibodies, hormones, and other substances that regulate physiological functions in the body, promoting growth and development and providing energy. Food sources: Lean meat, eggs, legumes, and soy products. Symptoms of deficiency: Delayed growth and development, weight loss, fatigue, decreased resistance to disease, slow healing of wounds and fractures, slow recovery from illness, and nutritional edema.

Sugar. Main functions: Provides energy, helps burn fat in the body, and aids in the synthesis of proteins in the body. Food sources: Grains, tubers, and root vegetables such as potatoes. Symptoms of deficiency: Slow growth and development, weight loss, and fatigue.

Fat. Main functions: Provides energy, essential fatty acids, promotes the absorption of fat-soluble vitamins, and increases the palatability and satiety of food. Food sources: Vegetable oils, animal fats, fatty meats. Symptoms of deficiency: Essential fatty acid deficiency, fat-soluble vitamin deficiency.

Cholesterol. Main functions: An essential substance in the human body, maintaining the normal function of the spinal cord, brain, nerve cells, liver, kidneys, and skin. Cholesterol also has the effect of destroying tumor cells and other harmful substances. Food sources: Animal fats, egg yolks, shrimp, crab, and liver. In addition to food sources, the human body can synthesize some cholesterol itself. Symptoms of deficiency: Middle-aged and elderly people or those with poor fat metabolism should eat less food high in cholesterol.

Cellulose. Main functions: Stimulates digestive juice secretion and intestinal peristalsis, eliminates harmful substances from the body, affects lipid metabolism, lowers serum cholesterol levels, and helps prevent cardiovascular disease and diabetes. Food sources: Whole grains, legumes, vegetables, and fruits. Symptoms of deficiency: May cause intestinal cancer and cardiovascular disease.