BMI Isn’t Everything

I shared on social media the other weekend that I got a bit of a shock when I calculated my BMI and it was 24.2; too close to the overweight category for my liking. It would take a three kilogram gain to reach that status, which isn’t likely to creep up on me like the few kilo I had already gained, but I didn’t think that at the time!!

I had relaxed my usual eating standards over the recent school holidays, together with a  busy time with house renovations. Takeaways had increased, I was choosing quick energy options – even lollies! (we all have our moments) – and I was eating far too many crackers as a late afternoon snack (even if they were made from brown rice).

Anyway, back to BMI. Body Mass Index uses your height and weight to determine whether you lie within a healthy body weight range. It is calculated by the following formula:Related image

Between 18.5 and 24.9 is classified as a normal weight. Less than 18.5 is underweight. Between 25 and 29.9 is overweight and obesity is a BMI of 30 or greater.

Now for the average adult – like me – BMI is pretty accurate. Although it should be used as just one of the tools to measure healthy weight.

If you are an athlete or body builder with higher than normal levels of lean body tissue (muscle mass) BMI is less accurate as an indicator of being overweight. This is because muscle weighs more than fat and the BMI does not take this into account. Conversely, inactive people may seem to have an acceptable body weight according to their BMI, but have too much body fat. BMI is also less accurate in ethnic groups with smaller body stature (i.e. Asian ethnic groups).

WHERE your fat is on your body can also be an important sign of your risk of developing ongoing health problems, notably heart disease and diabetes. Carrying excess body fat around your middle is more of a health risk than if weight is on your hips and thighs.

Measuring your waist circumference is another great tool (and I would even go so far as saying a BETTER tool) that can help you to determine whether you are a healthy weight. To take your waist measurement simply find the top of your hip bone and the bottom of your ribs, breathe out normally, place a soft tape measure midway between these points and wrap it around your waist, then check your measurement.

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Regardless of your height or build, for most adults a waist measurement of less than 94cm for men and 80cm for women is what you want. Men with a waist circumference greater than 102cm and women with waist circumference greater than 88cm should definitely try to lose weight, as this is an indicator that a high level of fat coats internal organs such as the heart, kidneys and liver.

Waist to hip ratio takes things further. WHR is calculated by dividing waist circumference (in cm) by the circumference of the hips (in cm). As a general rule, the greater a person’s WHR the greater the risk the person will suffer from  health conditions associated with being overweight. A WHR of less than 0.9 for men and 0.8 for women is desirable.

Who needs to replace their scales with a measuring tape?


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