BMI is an objective measure of body weight using the ratio of height to weight, which has been proven to be highly correlated with the amount of body fat in a typical person. Body fat refers to the fat in the human body, and the amount of body fat expressed as a percentage is called percent body fat.
Body fat can be divided into visceral fat and subcutaneous fat, and the average man has a body fat percentage of 15-20%, while the average woman has a body fat percentage of 20-25%. Body mass index is used as a way to measure obesity. Although BMI does not take into account age, gender, and body size, this measurement became commonly used in the early 1990s.
2. What is BMI?
BMI is an objective measure of body weight using the ratio of height to weight, which has been proven to be highly correlated with the amount of body fat in the average person. According to the World Health Organization (WHO), a BMI of 30 kg/m2 or more is considered obese.
Body fat refers to fat in the human body, and the amount of body fat expressed as a percentage is called percent body fat. Body fat can be divided into visceral fat and subcutaneous fat. The average man has a body fat percentage of 15-20%, and the average woman has a body fat percentage of 20-25%. A higher than average body fat percentage increases the risk of cardiovascular diseases such as diabetes, hypertension, and hyperlipidemia.
Body fat percentage is used as an important indicator to evaluate physical performance and personal health, and it is used as an obesity index to quantify the percentage of fat in the body.
3. Overeating and Obesity
Obese people tend to eat more than people of normal weight. Although overweight people say they eat less than others, their reports are not accurate and objective measures usually show that obese people eat more.
Obese people especially eat foods rich in fat, which has a higher caloric intensity than carbohydrates or proteins, so they may eat less, but they are consuming more calories. Overweight people also tend to be less physically active than lean people, and this can contribute to their excess weight.
Weight alone should not be considered when measuring obesity because some people have smaller skeletons and others have larger skeletons, and some people’s weight may be muscle and some may be fat.
Muscle tissue and bone weigh more than fat, which is why some people can weigh more than a normal weight person but be leaner. Traditionally, charts that provide normal weight ranges for different heights and body sizes are used as a basis for determining normal weight and overweight.
One way to measure obesity is by measuring body mass index. BMI is expressed in kg/m2. BMI does not take into account age, gender, or body size, but it became commonly used in the early 1990s.
The U.S. National Task Team for the Prevention and Treatment of Obesity (2000) agreed that while neither weight charts nor BMI measure body fat, BMI can provide a baseline for measuring overweight and obesity. They defined overweight as a BMI of 25-29.9 and obesity as a BMI of 30 or higher.
4. Is obesity unhealthy?
Overweight and obesity are undesirable from a social perspective. However, their health effects are less clear. These effects depend in part on the degree of overweight and the distribution of fat in the body.
In general, the relationship between weight and poor health is U-shaped, meaning that people who are very lean or very heavy have the highest risk of all-cause mortality (Glegal, Graubard, Williamson, & Gail, 2005). It has also been argued that being underweight is not as dangerous as being obese and that being underweight may be healthier than being of normal weight (Pinel et al., 2000).
In a large German study (Bender, Trautner, Spraul, & Berger, 1998), there was no association between obesity and all-cause mortality in men with a BMI of 32 or less, and only a weak association in women in this range. Only at BMI scores of 40 and above did the odds of all-cause mortality more than double for both men and women.