In our time, the problem of obesity care for more than 50% of the adult population of the earth. There are lots of various ways to lose weight. But there are also those who want to recruit as it is not surprising. Statistics says that only Every sixth person was satisfied with his body. Gain weight, as practice shows, is much more complicated than it reset. And this little one wrote. Causes of underweight there are many, the main ones are: – – Malnutrition – – Wrong way of life and lack of rest – – Parasites – – Hormonal disorders – – Inflammatory processes and diseases – – Disorders of pancreatic function or thyroid glands and digestive system – – Type constitution and other things Before that can be done, we must clearly understand what area lies the problem lack of weight – health (you have a serious lack of weight) or aesthetic (you just do not like your exterior form or if you want to improve it). For this purpose the rate of body mass index (BMI), which determine the suitability of your weight to your height and weight to assess whether inadequate. It is calculated by the formula bmi (measured in kg/m2) = body weight / weight in meters. Currently, the correspondence between the mass and the growth of man and his mass index is usually taken as follows: bmi of 15 or less – Sharp underweight bmi 15-20 – Inadequate (lack of) weight bmi 20-25 – Standard bmi 25-30 – Overweight bmi 30-35 and over – Obese If your bmi says that your weight is less than acceptable standards – for you to go to the doctor, and you should not do anything on their own to find out why.