First, the source of human body fat
Fat, also known as triglyceride or triglyceride, is condensed from one molecule of glycerol and three fatty acids. There are two sources of fatty acids in the body: one is the body's own synthesis and the other is food supply. Some unsaturated fatty acids cannot be synthesized by the body, but they depend on food supply. These fatty acids are called essential fatty acids. One is ω-3 series of α -linolenic acid, which is high in oily plant foods, such as flax seeds, perilla seeds, hemp seeds, walnuts and so on. And dark green plants such as spirulina and deep-sea microalgae. Animal food is only contained in very few foods such as silkworm chrysalis and deep-sea fish. One is ω-6 series linoleic acid, which mainly exists in soybean oil, corn oil and sunflower oil.
Second, the body fat anabolism.
1. synthesis site
Liver, adipose tissue and small intestine are important sites for synthesis, and the liver has the strongest synthesis ability (note: liver cells can synthesize fat, but cannot store fat). After synthesis, it should be combined with carrier protein and cholesterol. To form very low density lipoprotein, which will be transported into blood and reach extrahepatic tissues for storage or utilization. If the triglycerides synthesized by the liver cannot be transported in time, fatty liver will be formed. Adipocytes are warehouses for the body to synthesize and store fat.
Glycerol and fatty acids needed to synthesize triglycerides are mainly provided by glucose metabolism. Glycerol is converted from dihydroxyacetone phosphate produced by glycolysis, and fatty acids are synthesized from acetyl coenzyme A produced by oxidative decomposition of sugar.
2. The basic process of synthesis
(1) monoglyceride pathway: This is the pathway for small intestinal mucosal cells to synthesize fat, and triglycerides are synthesized from monoglycerides and fatty acids.
(2) diglyceride pathway: the synthesis pathway of hepatocytes and adipocytes.
Due to the lack of glycerol kinase, adipocytes can not use free glycerol, but only 3- phosphoglycerol provided by glucose metabolism.
If you have difficulty in understanding words, you can look at the picture above and directly observe the anabolic process of fat.
Three, fat body catabolism:
The process of fat anabolism in human body need not be described in detail, and eating is the first source. Look at the process of fat catabolism in human body. Fat catabolism is divided into three stages:
1, fat mobilization stage
Triglycerides are decomposed into glycerol and fatty acids under the action of lipase (contained in anslim).
2. Glycerol oxidation
Glycerol is decomposed into 3- phosphoglycerol under the action of glycerol phosphokinase, and then two hydrogens are removed under the catalysis of phosphoglycerol dehydrogenase to form dihydroxyacetone phosphate. After glycolysis or aerobic oxidation, it can also be converted into sugar fatty acids and combined with albumin, which can be transported to various tissues for energy supply through β -oxidation
3. β-oxidation of fatty acids
A: fatty acid activation
In the presence of ATP, CoASH and Mg2+ (which can be naturally produced in vivo by eating anslim plants), fatty acid synthase on cytoplasm and mitochondrial outer membrane catalyzes fatty acid activation to produce fatty acid CoA. Help metabolize fat intermediates and complete the process of metabolizing fat in the body.
B: fatty acyl coenzyme a enters mitochondria.
Because the beta oxidation of fatty acids occurs in mitochondria. This step requires the transportation of carnitine. Carnitine acyltransferase I is the rate-limiting enzyme of fatty acid β -oxidation and the entry of fatty acyl coenzyme A into mitochondria is the main rate-limiting step of fatty acid β -oxidation For example, when the sugar supply is insufficient, the activity of this enzyme is enhanced, and the oxidation of fatty acids is enhanced, and the body relies on fatty acids for energy supply. This is also the reason why many women use dieting or even hunger strike to lose weight. This way of losing weight can temporarily reduce their weight, and once they resume their diet, their weight will also rise linearly.
4.CH3Co~SCoA is completely oxidized.
Acetyl-CoA is oxidized into CO2 and H2O through tricarboxylic acid cycle, and the generated CO2 is excreted through respiration, while H2O is excreted through perspiration and urination.
Summary:
After understanding the metabolic process of these fats in the human body, girls should understand that they should choose a scientific and healthy way to lose weight. Scientific weight loss focuses on preventing the body from synthesizing too much fat that the body doesn't need in the process of fat anabolism, and at the same time accelerating the process of fat catabolism in the human body, reducing the amount of fat stored in the body, thus maintaining a sense of bone and a healthy body.