By Dr. Sundus Morgan

Many people want to know the answer to this question: how much should I weigh? However, there is not one ideal healthy weight for each person, because a number of different factors play a role. Arguably, a more accurate indication of whether we are at a healthy weight is the Body Mass Index (BMI) which takes into consideration both weight and height. Dr. Sundus Morgan at IMC, Katong, tells us about what we need to know.

What does ‘BMI’ stand for? What do the various

BMI categories mean? BMI gives you an idea of how your weight compares to common values and is calculated as your weight in pounds divided by the square of your height in inches, multiplied by 703: BMI = lbs/in2 x 703.

Body mass index (BMI):

Underweight - BMI is less than 18.5

Normal weight - BMI is 18.5 to 24.9

Overweight - BMI is 25 to 29.9

Obese - BMI is 30 or more

Can I calculate BMI myself?

This is very simple to do and there are many online tools that can be used. All you will need is your height and weight, then use the formula BMI = lbs/in2 x 703. If you feel you would like support with your BMI or would like a health screening International Medical Clinic offers a variety of health checks which could be a starting step to managing your weight and overall health.

What does a BMI tell doctors and are there limitations in what it tells us?

BMI is a useful tool that allows doctors to objectively look at weight and evaluate how this affects risk of diseases that are linked to obesity or being underweight. Together with other tests, BMI values can be helpful when discussing healthy lifestyle measures and treatment options.

There are limitations when using BMI that need to be considered. The measurement is based on an average distribution of body fat, including ‘intra-abdominal fat’ – the fat deep inside your stomach cavity rather than under your skin. People of Asian origin, have higher intraabdominal fat, so BMI calculations will give inaccurately lower readings. The World Health Organisation has recommended that some Asian groups should be considered overweight if their BMI is 22-25 and obese with a BMI of 26-31.

Likewise, for people who are very muscular BMI may be inaccurate because these people have lower body fat levels, which means BMI results may be inaccurately high. For people over 60, muscle mass tends to drop and body fat rises so this will affect BMI calculation and should be taken into consideration, as well.

Alternatives to BMI are ‘waist to hip’ and ‘waist to height’ ratio, which take into account intra-abdominal fat and abdominal waist circumference. A recent study found that the most accurate way of predicting your whole-body fat level was waist to height ratio.

Can we calculate BMI for children?

Yes, BMI be can used for children using the same calculation, however it is interpreted differently compared to adults. Age and gender specific percentile charts are used to interpret a child’s BMI and show a child’s relative position among children of the same age and gender.

What are the risks associated with a high BMI?

Having a high BMI and being in the ‘overweight’ or ‘obese’ category, significantly increases your risk of a number of medical conditions including type 2 diabetes, heart disease and cancer.

What are the global trends of BMI in western countries?

It is evident to see that the global trend of BMI in Western countries is rising mainly due to the overconsumption of food. Consequently, there has been a rise in medical conditions related to obesity. In the United States obesity is responsible for 6–10% of national health expenditures and is 2–4% in other developed countries.

What should I do to reduce my BMI?

Make realistic and sustainable changes now. Walk the few stops instead of taking the bus to your destination, use the stairs instead of the escalator or set a timer and get up from your desk every so often to walk around the office rather than sitting at your desk for hours on end. Find a sport or activity you enjoy that does not feel like a chore and that fits into your lifestyle.