Recent Posts
-
Admin
Feb
28
The Alphabet Soup
February 28, 2007 | Comments Off
…..or ways to tell you how fat you are.
We set out at the beginning of the year to alter our sedentary ways and set some aggressive fitness goals. J’s running a marathon in May, B’s knee problems have put an end to those aspirations, but she’s trying to become an ace swimmer and lifting some heavy weights. Then there are the winter weekend activities like skiing.
Getting back into the thick of things has not been that hard, although the urge to sleep in is high (this blog is keeping us up late too). And we’ve been lucky with no injuries.
At our local gym, they tugged our loose fat with calipers and told us that we both had roughly 25% body fat. We set a goal of getting that down to 18-19% in six months. Well, that was six weeks ago and in couple of weeks we will get another reading. J wanted to figure out whether there were other methods and metrics out there that could avoid getting pinched in seven spots.
Sure enough, BMI, BIA, DXA, HSW, HDL and LDL surfaced in addition to SMT (Skinfold Measurement Test) which is just a fancy term for caliper pinching. [It goes to prove that nothing is official unless you have a TLA (Three Letter Acronym) associated with it... ]
BMI (or Body Mass Index) is calculated very easily. Just divide your weight in Kg by the square of your height in metres.
For example, a person weighing 60 Kg and 1.7 metres tall has a BMI of 20.76. Calculate your BMI here. The normal range is supposed to be between 18 and 25, with people below 15 termed underweight and those over 30 deemed obese. Everyone from WHO to UNICEF to fast food corporations are interested in BMI for obvious reasons, but it seems like it has limited use beyond grouping people.
At an individual level, the BMI calculation just treats the body like a homogeneous cylinder which it most certainly is not. It therefore doesn’t compensate for differing body types and is especially problematic for athletes who have higher muscle mass. Additionally, for South Asians the range of acceptable BMI is lower than that for Caucasians. This goes hand in hand with the fact that South Asians have a tendency to have high LDL/HDL cholestrol ratio.
HDL or high-density lipoprotein is known as the “good” cholesterol because a high level of it seems to protect against heart attack. A HDL cholesterol level of less than 40 mg/dL increases the risk for heart disease. LDL or “bad” cholestrol of less than 100 mg/dL is the optimal level. A high LDL level (more than 160 mg/dL or 130 mg/dL or above (if you have two or more risk factors for cardiovascular disease) reflects an increased risk of heart disease.
BIA (Bioelectrical Impedance Analysis) is a technique where a small current is passed through the body. Muscle conducts better than fat owing to larger water and electrolyte content and this allows a water content measurement which is then converted to a body fat percentage. A high error margin in the calculation prevented the adoption of this technique until recently. You can get bathroom scales with inbuilt BIA for around 100 bucks.
DXA (Dual-energy X-ray Absorptiometry) is the most accurate technique to get a body fat reading and is typically used to scan for osteoporosis. Clearly is an overkill for this application, and needless to say it is prohibitively expensive.
HSW (Hydro Static Weighing) was traditionally used prior to DXA and still is the second most accurate technique. As the name suggests, the subject is weighed under water. Since muscle and fat have different densities it can be used to determine body fat percentage.
For now we have decided to continue with the SMT. Although this technique is not great for absolute measurements, it may work for measuring progress – provided the same pincher pinches the same spots the same way the second time around. Our next measurement is in couple of weeks – stay tuned.
Talking of soups, check out Alanna’s event at A Veggie Venture.
Filed Under: body-mass-index, fitness, MUSINGS, NUTRITION, skinfold-measurement-test
|
