Obesity – Current Trends and Measurements Used to Define Obesity

Obesity may be defined as a condition in which excess fat in the body accumulates to the extent that health, both physically and psychologically, is affected. It is not merely a problem of aesthetics and beauty, but a condition which is chronic and relapsing, and can cause significant medical illnesses and a reduced lifespan. The estimated cost of obesity in developed societies is between 2 and 7% of total health care cost.

In all developed countries, the prevalence of obesity is increasing across all age groups. What is of particular concern, is that, our children are also becoming increasingly obese. In 2000, the School Health Survey in Singapore reported that the prevalence of obesity was 10.8% in children aged 6-7 years, 14.7% in children aged 12-13 years and 13.1% in those aged 15-16 years. Onset of obesity in childhood increases the likelihood of obesity in later life.

Obesity is most commonly caused by a combination of excess dietary calories, the lack of physical activity and genetic susceptibility. A small proportion of cases are due to secondary causes such as genes, endocrine disorders, medication or psychiatric illness.

Diagnosis and Classification of Obesity:

The Body Mass Index

The Body Mass Index, or BMI, is the recommended index to define overweight and obesity, as it is highly correlated with body fat percentage. It is derived by the simple formula:

BMI = Weight (in kg) divided by Height2 (in m2)

The current WHO guidelines for adults uses a BMI cut-off of 25 to define overweight and 30 to define obesity. Based on body fat equivalence and risk of associated diseases, the cut-off for Asians is 23 and 27.5 respectively.

Waist Circumference

Visceral fat, or intra-abdominal fat, is strongly associated with cardiovascular risks, however, it can be measured only by CT and MRI scans. The most practical way for assessing this intra-abdominal fat, is to measure waist circumference, an approximate index of intra-abdominal fat.

You would be considered High Risk if:

You are male and your waist circumference is 102 cm (90 cm for Asians) or more.

You are female and your waist circumference is 88 cm (80 cm for Asians) or more

Look out for articles coming up on: Conditions associated with Obesity and Management of Obesity.