Health advice can often be confusing, not to mention conflicting. With improvements in science and technology come new findings and information for optimising health and avoiding disease.
A new analysis has added to the understanding of why some obese people will not develop chronic illnesses compared with someone who has excess abdominal fat but is not considered too overweight.
Recent findings published by Frontiers in Public Health (FPH) ramped up the warning that identifying excess body fat was increasingly pointing to a preventable epidemic of chronic disease in developed countries.
The study is questioning total reliance on the body mass index (BMI) to predict health, even though it has for years been used to monitor optimal body weight. Your BMI is calculated by dividing your weight (in kilograms) by your height squared (in metres). For instance if you are 1.7m tall and weigh 70kg, the calculation would be 1.7 multiplied by 1.7 = 2.89. Divide this into 70 and you end up with a BMI reading of 24.2. This result indicates you are in a healthy weight range. Much lower than this suggests you are underweight and much higher means you are overweight or obese.
However, BMI alone is not always the best indicator, as it does not take into consideration age, ethnicity, gender, and body composition.
Waist circumference is perhaps a better indication of whether you are carrying excess body weight compared with BMI. Although it only measures for fat around the middle, this is the most risky area of the body to carry excess weight. Having too much fat around your waist places you at a greater risk of developing serious conditions including Type 2 diabetes, heart disease and some cancers.
The FPH research compared the chances of developing a disease in two distinct groups of overweight people – Metabolically Healthy Obese (MHO) and Overfat. MHO people, who despite having a BMI greater than 30, could process insulin better and had “fewer (or other) cardiometabolic abnormalities than typically obese people.
“Within these, being overfat is the critical factor that confers risk for Type 2 diabetes and CVD associated with adiposity,” the study said. The researchers analysed weight circumference comparisons in relation to hips and height.
It reported that abdominal fat distribution measured through waist circumference, waist-to-hip ratio and waist-to-height ratio (WHtR) were “very useful”.
“The WHtR may be the single best clinical indicator of health risk as it can be used throughout childhood, into adult life, as well as throughout the world (in all ethnic groups).
Here’s The Heart Foundation’s advice on how to measure your waist:
- Find the top of your hip bone and bottom of your ribs
- Breathe out normally
- Place a tape measure midway between these points and wrap it around your waist
- Check your measurement
Based on World Health Organisation and National Health and Medical Research Council guidelines, a measurement above 80cm for women and 94cm for men is an indication that you may be carrying excess belly fat and, therefore, are at risk of chronic disease. Unlike BMI, waist circumference does not vary based on your height.
The best way to ensure that you are maintaining a healthy body weight is to use BMI in combination with waist circumference ratios. As always, your GP is your best point of contact if you’re worried about your body weight.