How is body fat formed?

The accumulation of fat in the body will cause obesity, and obesity not only affects the body shape, but also poses a threat to health. Therefore, we also need to understand the reasons for the formation of fat in the body so that we can better lose weight and maintain our figure.

1. First of all, it should be pointed out that the process of fat synthesis itself is complex and not easy to explain. The following is an inference made under the most simplified circumstances: Theoretically, 1 gram of fat can release 37 kJ of energy, about 9 calories, when completely oxidized in the human body. According to the calculation that the human body's efficiency in converting carbohydrates into ATP is about 30%, carbohydrates containing 1,000 calories can generate a maximum of about 300 calories of energy in the form of ATP when completely converted in the body, and the rest is dissipated in the form of heat.

2. Assuming that all 300 calories are used to synthesize fat, and 9 calories can synthesize 1 gram of fat, then 1000 calories can be converted into 33.3 grams of fat. However, in fact, de novo fat synthesis is not the reverse process of fat oxidation. It requires more energy. That is to say, 1 gram of fat can be oxidized to release 9 calories of energy, but 9 calories of energy are not enough to de novo synthesize 1 gram of fat. If the synthesis of fat requires twice the energy of oxidation, that is, 18 calories of energy are required to synthesize 1 gram of fat, then 1000 calories of carbohydrates can ultimately only synthesize 16.7 grams of fat.

3. According to your requirements, in addition to meeting the daily needs of the body, to synthesize 10 grams of fat, you need to consume an additional 600 calories, which is equivalent to 100 grams of potato chips, or 300 grams of steamed buns or 550 grams of rice. Simply put, if you want to gain 10 grams of fat, you have to force yourself to eat a pound of rice after you are full (this also requires good absorption, because the previous assumption is that the food is completely converted). Supplement: The de novo synthesis of fatty acids is a very energy-consuming process. In fact, the body synthesizes fatty acids from some lipid precursors in most cases. For example, the synthesis and decomposition of glycogen. It is a very wasteful process to synthesize glycogen from monosaccharides and then decompose glycogen into monosaccharides. Because the amount you consume is large enough, the body cannot absorb it and it has to be "wasted". Do you understand what I mean? The fat conversion efficiency mentioned above is an estimate and is not accurate enough.

4. In addition, the synthesis of fat varies from person to person and between men and women. The human body has other ways to regulate the synthesis and decomposition of fat and will not allow it to continue to accumulate. Those who are overweight have a disordered regulatory system in their bodies in addition to excessive nutrient intake.