Thinness or underweight is one of the health conditions that lead to many complications in many cases, and the incidence of thinness in many areas of the world because of poor malnutrition of the population of those regions, and in developed countries there are many cases of thinness Which have very different causes from those in poor countries.
There are many reasons that lead to the disease of thinness, but you must differentiate first between the thinness of disease and normal thinness, as the normal thinness that can be in the nature of any person or in the framework of maintaining the body from obesity is not harmful at all, but there are Many studies recommend that an adult be closer to thinness in order to avoid future cardiovascular disease and tumors. As for excessive thinness or pathology, it leads to many health complications that affect the human lifestyle and prevents him from exercising his daily activities normally.
Genetic factors control the formation of bone and muscle mass in humans, and control the efficiency of the internal organs of the body in terms of storage of energy and fat and burning calories, does not mean that the genetic factor that the thinnest father and mother reason But there are several other factors that control the inheritance of the gene from the family, where the father and mother can be completely non-hospitable and have children or one of them as well, and vice versa.
The other, most prevalent, factor in the world is malnutrition, the most prevalent because millions of people in poor and developing countries in Africa, Asia and South America suffer from poverty and the inability to provide basic life requirements, as well as natural and climatic conditions that often do not allow Except that the body is in that form.
The third factor in the order is the incidence of some diseases that lead to the loss of the body weight and turn to extreme thinness, such as anemia, chronic anemia, anemia, liver and kidney disease, as well as tumors and treatments that lead to weight loss significantly. These cases are more prevalent in developed countries where tumors are more likely than other poor countries due to the nature of food and the heavy production of industrial products and the impact on the health of the individual.