BMI and Healthy Weight
Body Mass Index (BMI) is a tool indicating the ratio of body weight of a person to his/her height. BMI is calculated on the following formula: weight(kg)/height2 (m2).
Initially BMI was introduced for statistical estimating of population, especially of people leading sedentary life.
BMI standard hasn't been the same since it was first introduced. As a result of the third National Health and Nutrition Examination Survey (NHANES III, 1988-1994) BMI cutoff points changed. So if you had considered your weight to be normal with BMI up to 27.8 (for a man) or 27.3 (for a woman) after the changes everybody with BMI over 25 became overweight.
Due to the changes introduced during NHANES III almost HALF of the USA population is overweight. According to the Survey, about 59% of American men and 50% of women have BMIs over 25, so they are regarded as overweight.
According to his/her BMI a person can be regarded as underweight, normal or overweight to a greater or lesser extent. The BMI table below will help you estimate your present body state.
|Category||BMI range ( kg/m2 )|
|Severely underweight ||less than 16.5|
|Underweight||from 16.5 to 18.5|
|Normal||from 18.5 to 25|
|Overweight||from 25 to 30|
|Obese||from 30 to 35|
|Clinically Obese||from 35 to 40|
|Morbidly Obese||above 40|
Body Mass Index is often used by physicians and also by general public as an indicator of whether a person is in a health risk group or not. Modern doctors tend to attribute higher health risks to people whose BMI indicates that they are either overweight or obese. Being overweight or obese can lead to increased risks of:
- Certain cancers
- Fatty liver disease
- Gallbladder disease
- Heart disease
- High blood pressure (hypertension)
- High cholesterol
- Sleep apnea
- Type 2 diabetes.
If you turn out to belong to a risk group remember that even a slight weight loss can decrease health risks.
Besides, BMI is not a universal perfect tool. It has a number of limitations so you can't rely on it totally.
- BMI standards are applicable to people of the European type. So if you are an American or European person these standards are more or less correct for you. But Southeast Asian body types require lower standards. For example, normal BMI in this case ranges from 18.5 to 22.9.
- BMI standards are different for kids. Besides, there are special Child Growth Charts of height weight and body mass index. They help you judge a child's height and weight in relation to other children of the same age and race/ethnicity.
- Gender also influences figure types. It is generally known that women have higher body fat percentage than men. But there are no officially accepted BMI standards different for men and women.
- BMI doesn't demonstrate body fat or body muscle percentage. That means that a healthy strong athlete can be ranged as overweight.
BMI and attractiveness
A lot of people tend to think that normal BMI is a guarantee of physical attractiveness. Some research works have been carried out to find the interdependence of BMI and attractive appearances. But still there is no comprehensive evidence showing that people with lower BMI are more attractive.
Scientists have discovered that the idea of female attractiveness is often connected with Waist-Hip Ratio. Women with a 0.7 WHR (waist circumference that is 70% of the hip circumference) are usually rated as more attractive by men from European cultures (Singh, Devendra; Young, Robert K. (2001-Jun-27). "Body Weight, Waist-to-Hip Ratio, Breasts, and Hips: Role in Judgments of Female Attractiveness and Desirability for Relationships". Ethology and Sociobiology 16: 483-507). It turns out that a proportional female body is very attractive irrespective of a woman's BMI.
BMI is not the only way of body measuring. Waist-Hip ratio, Body Fat and Body Water percentage are also used for estimating body attractiveness, health and health risks.
Most of body's weight is made up by water (50-70%). So after drinking much liquid you may be surprised by weighing more than usual. Nevertheless changes in your weight would not mean that you've become fatter. In comparison to BMI, which is based on your weight, Body Fat and Water percentage will actually indicate how fat you are. Thus a healthy athlete with an "overweight" BMI will be far from being fat according to Body Fat percentage.
Body Fat and Water percentage can be estimated by the bioelectrical impedance analysis. The analysis is based on the fact that fat-free body mass (muscles, water) is a good electricity conductor. During the bioelectrical impedance analysis the body tissues opposition to an electric current flow is measured. It gives the idea of fat-free body mass percentage together with the percentage of Body Fat.
Body Fat and Water can be easily counted at home nowadays. There are various body fat meters available today. And one of the easiest devices to use is modern bathroom scales.