Scientific Assessment of Obesity: Mastering the Standards Lays the Foundation for Effective Weight Loss

Criteria for Determining Obesity

Different measurement methods have different criteria for determining obesity.

(1) Relative Standard Weight

Obesity degree = Standard weight / (Actual weight - Standard weight) × 100%

An obesity degree of ±10% is within the normal range; >10% is overweight; >20% is obese; 20%–30% is mild obesity; 30%–50% is moderate obesity; >50% is severe obesity; >100% is morbid obesity.

(2) Body Mass Index (BMI): The World Health Organization (WHO) (1989) recommended standard is shown in Table 2-6. This standard was developed based on data from Caucasians in Europe, and there was no internationally unified standard before that. The BMI for obesity and overweight in the Asia-Pacific region is significantly lower than the WHO standard (Table 2-7). China's BMI also differs from other countries in the Asia-Pacific region, but currently there is no independent BMI standard; the Asia-Pacific standard can be temporarily adopted. (3) Waist circumference: Compared with weight, BMI, and WHR, waist circumference better reflects body fat distribution. The WHO recommended in 1998 that waist circumference standards for European men and women should not exceed 94cm and 80cm respectively, while the Asia-Pacific region currently recommends 90cm and 80cm.

(4) WHR: In Caucasians, a WHR greater than 1.0 and 0.85 is defined as obesity. In the Asia-Pacific region, a WHR greater than 0.95 and 0.85 is used for abdominal obesity in men and women, but waist circumference is more suitable for detecting abdominal obesity than WHR.

(5) Obesity is defined as a waist circumference greater than hip circumference or an abdominal height exceeding the height of the sternum when lying flat.

(6) Density method measurement standard

(7) Childhood obesity: The methods for detecting obesity in children and adolescents differ from those for adults. The age-height-weight standard method is recommended. Internationally, an age-corrected BMI-age chart is proposed, with BMI greater than 95% and 85% of the corresponding age's BMI being considered obese and "risk state," respectively. Currently, there is no BMI-age chart in my country.

(8) In recent years, some people have proposed the concept of metabolic obesity with normal weight, which is classified according to height and weight. These patients have a BMI between 20 and 27. These patients have a normal BMI but only abdominal fat accumulation.