The number on the scale rarely tells the whole story. It signifies the total weight of your body, which includes your organs, bones, water content, muscles and fat. But it isn’t a good way of judging your body composition, or the distribution of that weight. It does not, for instance, take into account the ratio of fat to muscle tissue. That skinny cousin you envied may actually have reason to worry, because she may have a far higher fat percentage than you do, if you work out every day and she doesn’t. And your bulk could be muscle, which weighs more than fat does.
Going beyond the weighing scale, here are other ways to assess weight. The idea is to use a combination, because nothing tells the absolute truth. The ultimate goal is to attain optimal health through an active lifestyle.
Body mass index
Usefulness in
estimating obesity
The BMI may be used to make a simplified differentiation between someone of normal weight, versus a person who is over-weight or obese. We don’t use it for children, and use it as a rough guide for young adults who are still developing. The number does not take into account muscle mass and fat percentage. The danger is that it could be misleading for very thin or very muscular people. It is, however, a good way of gauging those who are at risk for lifestyle diseases, such as diabetes and hypertension.
You measure your BMI by dividing your weight in kg by your height in metres squared. The current cut-off values for India are lower than the ones for our Caucasian counterparts, because we seem to be at greater risk of lifestyle diseases (diabetes, hypertension).
In the Indian scenario, anyone with a value under 18.5 kg is said to be underweight; 18.5 to 23 is within the normal range; 23 to 27.5 is overweight and over 27.5 is obese. There are then three levels of obesity as well.
Waist circumference
Usefulness in
estimating obesity
An easier and better way of gauging health risk is to measure the waist. Why waist circumference and not the circumference of the thigh or arm? Abdominal obesity is known to be a high-risk factor for heart disease, unlike fat accumulation in the limbs.
Again cut-off values for the India are lower than our Caucasian counterparts: 85 cm for men and 80 cm for women. Anything above, and you are at risk. Measure at the level of the upper margin of your pelvic bone, the edge of which you should feel at the side of your waist. This usually (not always) corresponds to your navel. Don’t compress the skin or drift towards the narrowest part of the waist.
Waist-hip ratio
Usefulness in
estimating obesity
If you measure your waist and the hips (around its broadest part), divide the two to get a value considered another measure of health. However, a person who has a waist circumference of, say, 28 inches (within the normal range) and has wide hips, measuring say 32 inches, falls in the .87 or not normal range. What is considered acceptable is .85 and below for men, and .75 and below for women.
Body composition
Usefulness in
esti mating obes ity
Bioelectrical impedance analysis (BIA) is a method of assessing fat percentage in the body. It is typically measured with a machine that you often find at a gym. The machine evaluates the amount of fat, both within the cavity of the body and beneath the skin. Within a minute or so, it provides an approximate value. Discrepancies occur, depending on the level of hydration or water accumulation in the body, time of day, and gender. Values may be used for follow-up and progress.
A minimum amount of fat is required for the human body: 13-14% in women and 5-6% in men. When fat percentages drop lower than these values, other health issues develop. The absorption of fat-soluble vitamins A, D, E and K is compromised, gut and brain health deteriorate, immunity falls, susceptibility to disease and infections increases and fertility decreases. There is also an increased risk of heart disease and you begin to age faster.
As per the American College of Sports Medicine, an athletic fat percentage is less than 17 in women and less than 10 in men; lean is 17-22% in women and 10-15% in men; normal is 22-25% in women and 15-18% in men; above average is 25-29% in women and 18-20% in men; over-fat is 29-35% in women and 20-25% in men; obese is 35+ in women and 25+ in men. You may be just the right weight, but your body fat percentage may reflect that you’re obese.
The other methods are skin calipers for skin fold thickness at various points (different for men and women) and girth measures, again at different points. These are calibrated according to standard formulae and charts, but are not accurate. A reliable method of measuring fat percentage in a clinical setting is by a DEXA scan, which is neither practical nor easily affordable. The most reliable method is by hydrostatic weighing in a lab setting . It is both impractical and unavailable for everyday use, but is interesting in that it is done underwater (yes, the person needs to get dunked in a tank and push out all air), using Archimedes’ principle.
The writer is an obstetrician/ gynaecologist, fitness, lifestyle consultant and author of Get Size Wise and Gain to Lose
