BMI ,Waist Size, Body Fat Indications of Your Healthy Weight

How Does Your Healthy Weight Measure Up?

We all come in different shapes and sizes. The healthy weight of one person could be far too low or high for another. Body Mass Index (BMI) , waist size and body fat are three measurements widely used today that together work as a good health indicator. They inform us how weight is distributed among muscles, bones and fat mass.

1. Body Mass Index (BMI)

   BMI was invented by the Belgian statistician Adolphe Quetelet in the 19th century. At the beginning, he created it only to help the French and Scottish armies to sort out the "average body size" suitable for joining the army. After prolonged development and promotion, the BNI indicator has been widely used worldwide. The calculation method is as follows:

   • A calculation that uses height and weight measurements to gauge how much body fat a person has.
   • Calculated by dividing your body weight (in kilograms) by your height in squared meters (m²).

   The World Health Organization revised the BMI index for Asians in 2000, because the physique of Asians is different from that of the people from Western countries. Most Hong Kong residents have Chinese ancestry, thus better to refer to the Asian standard:

   Western Standard1	Asian Standard2
   Below 18.5: underweight	Below 18.5: underweight
   18.5-24.9: normal	18.5-22.9: normal
   25-29.9: Overweight	23-24.9: Overweight
   30 or more: obesity	25 or more: obesity

   Click here to the BMI calculator to check your value and health risk.

   BMI can reflect the degree of obesity to a certain extent, it is worth noting that the data does not apply to children under 18 and women during pregnancy. In addition, BMI tends to overestimate the proportion of body fat in athletes and ignore their muscular physique; meanwhile, underestimates the degree of obesity in the elderly, or some adults that have less muscle.

   Generally speaking, even the appearance is similar in terms of height and shape, the athlete's BMI will be higher than that of the average person, because of the more muscles in the body. Relatively speaking, as the elderly or some people have less muscles, their BMI index will be lower.

2. Waist size

   Studies show that we carry extra fat around our belly rather than the thighs and hips. This increases the risk of developing health conditions associated with obesity, like high blood pressure and diabetes.³In other words, the measurement of waist circumference reflects the degree of abdominal fat accumulation and predicts the risk of various diseases in advance. Men with a waist circumference of more than 40 inches (about 90 cm) and women with more than 35 inches (about 80 cm), are considered "abdominal obesity". Special attention must be paid to diet, exercise, and weight control.

   Correct waist measurement method⁴

   1. Remove the clothing covering the waist, stand easily, and let your hands droop naturally.
   2. Use a soft ruler to go around the waist and adjust the height so that it can pass between the upper edge of the left and right intestinal bones and the lower edge of the ribs. At the same time, pay attention that the measuring tape is level with the ground, not squeezing the skin.
   3. Maintain normal breathing. At the end of exhalation, measure the waist circumference.
3. Body fat

   Unlike the traditional BMI method that is based on calculations of body weight and height, the body fat percentage measurement is based on a range of methods from the clinical-based hydrostatic test to the Caliper test at the gym and the home-use body fat scale. A healthy body fat percentage falls between 25 to 32%, while 33% or more is overweight.

   It must be noted that physiological differences predispose women to a higher percentage of body fat, while the ideal percentage also differs by age. Therefore, fitness experts recommend that women pay attention to where their fat is stored. For example, abdominal fat is bad and a sign of metabolic syndrome including heart disease.

How much body fat is ideal?

Age(years)	Body fat (%)
	Men	Women
20	8.5	17.7
25	10.5	18.4
30	12.7	19.3
35	13.7	21.5
40	15.3	22.2
45	16.4	22.9
50	18.9	25.2
55	20.9	26.3

How can I achieve a healthy weight?

BMI of over 25? Notice extra inches around your waist? Why not make some positive lifestyle changes today to bring the number down. Expert advice includes reducing the intake of oil, salt, sugar, alcohol; steam or roast instead of frying. In addition, each person is advised to exercise 3-5 times a week for at least 30 minutes and increase daily life activities such as walking and climbing stairs, etc.

A combination of regular physical activity + a low-fat balanced diet = the best way to achieve a healthy weight.

Sources

1. What's your BMI. NHS Choices. July 2013
2. Centre for Health Protection - ContentBody Mass Index Chart
3. Balkau B et al. International day for the evaluation of abdominal obesity (IDEA): A study of waist circumference, cardiovascular disease, and diabetes mellitus in 168,000 primary
4. 量腰圍 測三高 中老年病不上身