First of all, most thin people have no basic diseases, which is a process of our physical development. Especially for some junior high school students and senior high school students, they are in the period of physical development. If all nutrients are used to support bone development and metabolism, most people may lose weight if there is no overnutrition at this stage.
Especially for some boys, the developmental period is even extended to 18-20 years old. It is particularly difficult to gain weight during this period. We can all recall that in junior high school, high school or university, there are only one or two precious fat people in the class.
Secondly, if you are 30-35 years old, most people are used to being content with the status quo and have taken root in various positions. If you have worked in a post for a long time, the shortest way is to finish the work at hand, and your body will form a certain muscle memory and complete the daily workload with the least energy. Over time, coupled with relatively more social activities, it will naturally become obese.
If the body has been thin, then these problems are explained:
First, the congenital constitution is poor, the qi and blood are insufficient, and the acquired spleen and stomach transport and absorption function is poor. The nutrients eaten and the subtle nutrients of whole grains can't reach all organs of the body.
The second is the lack of certain nutrition. In today's modern society, overnutrition is greater than undernutrition. I wonder if you intend to control it.
If it is "thin", the nutritionist's understanding is lower than the value of "healthy weight". (Healthy weight is standard weight, which is lower than standard weight 10%- 15%, body fat is about 17% of body weight, and body fat content is less than one third of normal content) We call it "thin" or "too thin".
Of course, we still recommend those who are thin, as long as they live a normal life, because after all, they can't lose weight if they are fat. If you want to look plump, stick to exercise and gain muscle!