Standards for obesity

More and more people have realized the serious harm that obesity brings to the body. Because obesity will increase the risk of patients suffering from cardiovascular and cerebrovascular diseases, as well as diseases such as arthritis, obese patients must lose weight in time. Although we often hear the term obesity in daily life, most people are confused when it comes to the standard of obesity. The following article will explain the specific standards for obesity.

Standards and methods for judging obesity in children and adolescents

1. Height standard weight method:

The standard is based on well-nourished children and uses the 80th percentile weight of people of the same height as the representative. The standard stipulates that taking this weight standard as 100%, plus or minus 10% is considered normal. Any weight over 10% is considered overweight, and any weight over 20% is considered obese. This standard is recommended by the World Health Organization (WHO) and is limited to use for preschool children for maternal and child health purposes. my country applied this method in the 1985 National Student Physical Fitness and Health Study to establish corresponding height and weight standards for school-age children and adolescents.

2. Broca's simple calculation method

Standard weight (kg) = height (cm) - 100 (applicable to those under 165cm)

Standard weight (kg) = height (cm) - 105 (applicable to those who are 166 to 175 cm tall)

Standard weight (kg) = height (cm) - 110 (applicable to those above 176cm)

Women weigh 2.5 kg less than men.

This method has certain limitations, but it is still useful in roughly estimating whether you are overweight or obese.

3. Body density method

The measurement of body fat composition currently mainly uses indirect measurement methods, the most commonly used of which are underwater weighing method and skinfold thickness method. Both methods measure the body density and then use Brozek's body fat percentage calculation formula to calculate the body fat percentage, thereby calculating the body weight and fat-free body weight, so it is called the body density method.

(1) Underwater measurement method:

Underwater measurement is a relatively accurate method, and its principle is mainly based on Archimedes' buoyancy principle. The specific gravity of fat is as low as 0.9g/cm3, which is lower than water, while the specific gravity of the fat-free part of the body is 1.2 ~3.0g/cm3, which is higher than water. When the human body is weighed underwater, those with more lean body mass weigh more underwater and have a higher body density. According to this method, a person's volume and density can be calculated through underwater weight, land weight and water density.

Calculation formula: Human body volume = (land weight - underwater weight) / water density

Human body density = land weight / human body volume

Body fat percentage = (4.570 / body density - 4.142) * 100%

(2) Skinfold thickness method:

Skinfold thickness is a simple and economical measurement method. About 2/3 of adipose tissue is distributed in subcutaneous tissue. Therefore, by measuring the thickness of subcutaneous tissue, namely skin folds, the total content of human fat tissue can be inferred. The skinfold thickness method can reflect the content of subcutaneous fat, but it cannot reflect the fat hidden in the muscles, so this method has a certain error. But it is still a good method in group measurement.

4. BMI body mass index method or Quetelet coefficient method

This is a standard weight measurement method that has become popular internationally in recent years, using body mass index to study human obesity. The characteristic of the index is that it is less affected by changes in height.

The calculation formula is as follows:

BMI= actual weight (Kg)/height (m2)

Assessment: BMI between 20-24 is normal weight; BMI less than 20 is underweight; BMI between 24-26.5 is overweight; BMI greater than 26.5 is obese.

Quetelet stipulated that the standard body mass index for the human body is "BMI22", which is formulated based on various data from an immunological perspective. He believed that the index of 22 is a relatively ideal height and weight ratio.

Standard weight (Kg) = height (m)2 * 22 Obesity (%) = [actual weight (Kg) / standard weight (Kg) - 1] * 100%