In the past, we all think that a person becomes fat because he eats too much, and the energy he eats cannot be consumed, so it all becomes fat stored in his body, and this is indeed the root cause of obesity. However, over the years, with the understanding of obesity and research more and more in-depth, people began to find that, although fat is caused by excess energy intake, but will be affected by many factors, such as obesity genes, some people are born is easy to fat body, making them more likely to become fat than ordinary people. But it is not only genes that can influence obesity, our birth weight also determines whether we are prone to become fat. Physiologically, we gain weight because we have bigger fat cells or more fat cells. When a person has too many fat cells in his body, he has a greater ability to gain fat, so it is easier to gain weight and more difficult to lose it. And normally, the growth of the number of fat cells are before adulthood, because during this period the body is developing, cell division is stronger, and the body metabolism is also very strong, so with enough energy, fat cells will be secreted in greater numbers, and this process begins when we are still fetuses. Many mothers will eat a lot of nutrient-rich food when they are pregnant so that their children can get enough nutrition, resulting in excess nutrition, which not only makes them fat, but also allows the fetus to get an excessive amount of nutrition, although it is to meet the needs of development, but also forms a large number of fat cells, and once the fat cells are formed it is difficult to disappear, so those babies with high birth weight tend to be more likely than others become fat. Therefore, mothers should eat reasonably during pregnancy, rather than just supplementing nutrition, which not only reduces the pressure to lose weight after delivery, but also reduces the probability of the child becoming fat later, so that they can grow more easily.