How To Check Your Body Mass Index
One of the most important aspects to losing weight is keeping track of your progress. If you can’t tell if you’re losing weight, how are you going to know if your current calorie intake is too much or not enough.
How To Check Your Body Mass Index
The easiest way to track progress is by
monitoring your BMI – or Body Mass Index. This tells you how much of your total
body weight is actually fat. We need to track this because if you’re burning
off fat but gaining some muscle mass as well (from your workouts), your body
weight could remain the same, but your level of body fat could be reducing. So
weighing scales are not the best way to monitor your progress.
Here are some of the different ways you can
check and monitor your BMI:
Waist Circumference
Body fat tends to distribute differently in
men and women. In men, fat tends to accumulate around the inner organs of the
abdomen, such as the intestines, kidneys and liver (android fat distribution),
giving the body an apple-shaped appearance. This pattern of fat distribution is
described as abdominal, truncal or central obesity.
In women, on the other hand, fat tends to
accumulate around the hips and thighs (gynaecoid fat distribution), giving the
body a pear-shaped appearance.
While we all have some subcutaneous fat
(under the skin), this type of fat is not as harmful as infra-abdominal, or
visceral, fat. In sumo wrestlers, for example, the fat is mostly subcutaneous,
which means a low risk of heart disease. The heavy physical training that their
sport demands minimizes intra-abdominal fat.
Doctors have noted that certain conditions,
such as abdominal obesity, elevated triglycerides, low HDL (good) cholesterol,
high blood pressure and elevated blood glucose levels (diabetes), tend to
cluster in people.
The underlying cause of this cluster of
conditions (called metabolic syndrome) is thought to be abdominal obesity and
insulin resistance. Insulin resistance is a condition where the body does not
respond fully to insulin circulating in the body. This results in high blood
sugar levels. (Insulin is a hormone that the pancreas produces to lower blood
sugar levels.)People with metabolic syndrome are at increased risk of heart
disease, stroke and other conditions that result from a build-up of plaque in
the arteries. Blockages in the arteries can stop the flow of blood to the heart
and the brain. A gauge of the amount of intra-abdominal fat can predict if a
person has metabolic syndrome.
One way of estimating this is to measure
your waist circumference. If you reduce your waistline, even if your weight
stays the same, your risk of cardiovascular disease will fall. To get reliable
measurements, it is important to standardize the way you measure your waist
circumference.
What is the ideal waist circumference? Like
the BMI, body proportions differ in different populations, so each has its own
set of cut-off points:
Waist circumference and BMI together serve
as convenient and fairly accurate measures of body fat. If the BMI is high but
the waist circumference is normal, as with bodybuilders, there is no worry of
excessive body fat. If the BMI is normal but the waist circumference is large,
as with elderly men who have little fat around the face and arms but carry
around a pot belly, there is a worry of excessive high-risk intra-abdominal
fat.
Waist-to-Hip Ratio
This method requires the hip circumference
measurement in addition to the waist circumference measurement. In spite of
this extra step, there is no added benefit compared to measuring the waist
circumference alone.
Skinfold
This technique involves pinching the skin
and subcutaneous tissue in three to seven places on the body and using handheld
calipers to measure the skinfold thickness while exerting constant pressure.
The measurements are entered into a regression equation to estimate the body
fat percentage, which should ideally be less than 25% for men and less than 30%
for women.
There are a few drawbacks. First,
regression equations commonly used are derived from studies using Caucasian
cadavers, but we know that body composition differs between ethnic groups (and
between the living and the dead). The equation also assumes that subcutaneous
fat makes up a constant proportion of total body fat, but we know that the
distribution between subcutaneous and intra-abdominal fat is variable. Second,
unless the person performing the skinfold measurement is well-trained and
experienced, the results will not be very reproducible. Third, the greater the
degree of obesity, the harder it is to pinch a fold of skin to apply the calipers.