Your Body Mass Index (BMI)
The Body Mass Index provides a simple numeric measure of your “fatness” or “thinness”, allowing health care professionals to discuss over- or under-weight problems with you more objectively.
BMI consists of measuring your body weight and height and plotting them using a BMI chart (See Figure 1). It is a practical way to assess if your body weight departs from what is desirable relative to your height.
|Your BMI is|
The BMI does not apply in certain cases, such as if you are pregnant, breastfeeding, very muscular or under the age of 18.
Stated targets are based on data from European populations and may not be appropriate for all ages and ethno cultural groups. Compared with Europeans, the BMI cut-point associated with increased risk of type 2 diabetes and cardiovascular disease is typically higher for Polynesian populations and lower for Aboriginal and Torres Straight Islander populations and some Asian populations (e.g. Hong Kong Chinese, Indonesians and Singaporeans).
It is important to speak to your doctor about your individual weight if you are unsure. This chart is just a guide and may not apply to everyone.
Your Waist Circumference (WC)
Waist Circumference The purpose of determining waist circumference is to gain a measure of your amount of abdominal (or visceral) fat. This fat has been linked to increased risk of coronary heart disease and diabetes.
Measurement of waist circumference also provides information about where body fat is stored. Most people store their body fat in two distinct ways, often called the “apple” and “pear” shapes. These terms refer to where you carry your weight – around your middle (apple) or around your hips (pear).
It is generally accepted that for most people, carrying extra weight centrally (“apple shape”) increases the risk of developing heart disease and type 2 diabetes.
Carrying weight around the hips or thighs (“pear shape”) is associated with a lower cardiovascular risk than with centrally carried weight (“apple shape”).
The Best Measure
You have just learned the importance of taking a closer look at some measures to assess your body size and whether or not you have increased cardiovascular disease risk.
For many years, BMI has been the most used method to determine if a person is overweight. However, in recent years, it has been suggested that Waist Circumference might be a better measure of having an increased cardiovascular disease risk.
Evidence on ‘the best measure’ is conflicting. If you have concerns whether you are overweight or underweight or at risk, please discuss this with a healthcare professional.
Measuring Waist Circumference 1) Measure waist circumference directly on the skin. Clothing will affect the accuracy of your measurement.
2) Place the tape measure around your waist — just above the hip bone (see Figure 2). Make sure the tape measure is at the same height for the entire circumference. If the tape is angled, the measurement will not be accurate.
3) Take a deep breath, let it out and completely relax your abdominal muscles. Contracted abdominal muscles will reduce the measurement. Pull the ends of the tape measure snugly, but not firmly, toward each other. If the tape measure is pulled too tight, the skin will indent and the measurement will be too small.
4) Record your measurement. In order to track your progress over time, mark down the date, time and measurement in the table provided as a printable pdf file. Compare your results and changes over time.
Special waist circumference tape measures with colour coded markings (Green, Yellow & Red) at the significant WC cut off values for males and females (often indicated by ♂ and ♀ symbols respectively) are available which allow you to easily see where your WC falls in relation to the presently recommended guidelines for WC values. Ensure you are using the correct side of the WC tape measure according to your gender, and that the colour coding is in line with those shown in table 1 below.
If a regular tape measure is used (i.e. without colour coded markings), you can use the cut-off values in table 1 below as a guide.
Table 1. Waist Circumference cut-off values to help determine those at risk, according to sex and ethnicity.
* Europeans, Sub-Saharan Africans, Eastern Mediterranean and Middle East (Arab) populations use European category
† South Asians, Chinese, Japanese, Ethnic South and Central Americans use South Asian category
# The IDF (International Diabetes Federation) consensus group acknowledges that these are pragmatic cut-points taken from various different data sources and that better data will be needed to link these to risk.