Weight War: BMI vs BVI
There’s a weight war, did you know? The weight war will become more intense over the coming months with BVI taking center stage. So what is BVI? BVI means Body Volume Index, a measure considered to be more accurate than the more often used BMI.
Background: BMI was developed by Adolphe Quetelet over 150 years ago to measure body fat percentages. It’s a very long story but the index was effective in his day because most people were height and weight proportionate and participants of his sample data sets were homogeneous by nationality and occupation -namely soldiers (sources cite both Scottish and US soldiers so I don’t know but suspect Scottish to be more likely being that Quetelet was Flemish). These days, BMI is considered a poor alternative to measure body fat in its most common context namely that of assessing one’s health risks.
BVI isn’t the first BMI alternative (and contrary to claim wasn’t invented by Aston University but they did come up with a competing catchy acronym which as you know means everything). Another reason reason BVI may be increasingly used as a tool to measure body fat is that the technology they use (body scanners) is sexy. Okay, I’ll play it straight; BVI will be more accurate than BMI because it computes measurements of the body beyond height and weight. [Aston U. didn’t invent that either; innumerable others like the US Navy have been doing that for years.]
If you’ve been dissatisfied with your BMI results, I’m guessing you’ll be even less satisfied with BVI based on my trial run using a variety of calculators this morning. If you’re fat under BMI, you may be even fatter under BVI. I was.
My results showed appreciable differences between BMI and BVI calculations of body fat. Actually, there were big differences between BMI calculators period. For example, this site says I’m underweight (vanity weighing imo) and didn’t give me a percentage while another site reported my weight as normal (20.8%) but I could gain another 24 pounds and still be of “normal” weight within their reported range. Hmm. The last site I used reported my body fat percentage as 31.8% (!) meaning technically obese. I played with that calculator awhile. Either it is broken or the site is selling diet plans. I put in Sally’s measurements (she’s slender, built like a prima ballerina) and it also said she was over 30%. The summary conclusion of online BMI calculator results means you could shop around to find a percentage more to your liking. But I digress.
An official BVI calculator isn’t available online yet so I used an abbreviated calculator developed by the US Navy. I warn you the results will be painful. This calculator requires height, waist, hip and neck measurements. My score was 24.8% body fat. I think that was the most accurate result of them all. Just for grins, I put in my measures from five years ago when I knew my hydrostatic weight (the most accurate of accessible indices) and it came pretty close to it.
If you want to do the math yourself, the rough-cut BVI calculation (via) is:
Men: %BF = 495/(1.0324-0.19077(log(waist-neck))+0.15456(log(height)))-450
Women: %BF = 495/(1.29579-0.35004(log(waist+hip-neck))+0.22100(log(height)))-450
One last method used to calculate health risks –not to be confused with percentage of body fat– is the waist to hip ratio.