Stepping into modern society, many people have a high-fat diet and irregular meals. Some people like to eat midnight snack but don't like sports, and the pressure of life and work is great, which leads to the increasing number of overweight and obese people in China. According to statistics, China has more than 90 million obese people, surpassing the United States, and is known as the country with the largest obese population in the world. However, there are indeed a small number of people who are not fat and thin all the year round. What's going on here? In fact, there are many criteria to judge whether a person is fat or thin. At present, the most commonly used standard is body mass index. Body mass index is equal to kilograms divided by the square of meters. For example, a person's height 1.7m and weight 70kg, then his body mass index = 70 ÷ 1.7 ÷ 1.7 = 24.2. According to the regulations of our country, those whose body mass index is less than 18.5 belong to thin people; The body mass index of normal people should be greater than 18.5 and less than 24; Body mass index greater than 24 is overweight; A body mass index greater than 28 belongs to obesity. You can calculate your body mass index according to your height and weight. In addition to body mass index, there are many indicators to measure whether a person is fat or thin, such as body fat rate, waist circumference, muscle content, subcutaneous fat thickness and so on.

Generally speaking, the main reasons for weight loss are as follows:

First, genetic factors.

Why do some people always eat fat? That's because their genes are good. 20 1 1 year, the British magazine Nature published a research report completed by researchers from Britain, Switzerland, France and other countries. The researchers investigated the genetic data of more than 95,000 people, and found that about one person in every 2,000 people has an extra copy of a certain position of chromosome 16. The definition of ultrathin here is that the body mass index (BMI) is lower than 18.5, which is unhealthy. Explain why some people are thin, which is determined by their genes. Scientists are still studying how these lean genes cause human emaciation, and if the molecular mechanism is clarified, they can be used to treat obesity.

Second, the gastrointestinal function is not good, and the digestion and absorption ability is poor.

Long-term chronic gastritis, functional dyspepsia, enteritis, ulcerative colon cancer, Crohn's disease, etc., these patients have poor gastrointestinal function, poor digestion and absorption ability, and the nutrients they eat cannot be absorbed, which easily leads to weight loss.

Third, mental factors, anorexia.

People who welcome mental illness may also be thin. People who are in a state of anxiety, depression and mania for a long time don't eat at all and tend to lose weight. There are also anorexia patients, who deliberately cause and maintain eating disorders characterized by significantly lower weight than normal standards through dieting and other means. Anorexia patients mainly show strong fear of weight gain and obesity, extreme concern about weight and body shape, blind pursuit of slimness, obvious weight loss, frequent malnutrition, metabolic and endocrine disorders, such as female amenorrhea. In severe cases, cachexia and body failure may occur due to extreme malnutrition, which may be life-threatening. 5% ~ 15% patients eventually died of heart complications, multiple organ failure, secondary infection, suicide and so on.

Fourth, hyperthyroidism.

Hyperthyroidism patients tend to lose weight because of excessive secretion of thyroid hormone and accelerated metabolism. Although they eat a lot, their consumption increases and they tend to lose weight. Moreover, patients with hyperthyroidism often have poor gastrointestinal function and poor absorption ability.

Fifth, malignant tumors, diabetes, tuberculosis and other consumptive diseases.

Patients with malignant tumor are often malnourished in the late stage of tumor, which is seriously called cachexia. Because the tumor consumes a lot, or the tumor causes digestive tract obstruction, the patient can't eat it. For example, patients with gastric cancer, colorectal cancer and esophageal cancer. Malignant tumor, tuberculosis, chronic blood loss, systemic lupus erythematosus, diabetes, chronic atrophic gastritis, etc. All belong to chronic wasting diseases, resulting in negative balance of body energy.

Sixth, the diet is unbalanced.

Some people lose weight because they are picky eaters, partial eclipse, unbalanced nutrition, love snacks, do not eat staple food, and do not like fruits and vegetables. Cause malnutrition, lack of vitamins and trace elements in the body, and so on. This situation is common in infants and children.

These are common causes of weight loss. If you want to treat emaciation, you must first find the cause and then treat it symptomatically.