All Those Numbers

You weigh 176 pounds.  Your BMI is 26.6.  Your waist to hip measurement is 0.8.  Your body fat is at 24%. What is one to make of all this?  First, let us deal with the scale which will give you your weight in pounds or kilo. And that is all it tells us.  It doesn’t tell you how much of that weight is because you are big or small framed (boned) and it certainly can’t differentiate between how much is muscle (healthy) and how much is fat weight (unhealthy).  The number on the scale gives us a good idea about our health and weight, but it isn’t the whole story—at all.  Numerous times I have witnessed my clients walking in and getting ready for a weekly weigh in.  They feel so much better in how their clothes fit (the belt went in a notch this week) but the scale is still in the same place.  That is the displacement of lost fat by new found muscle from the person’s working out properly. So even though the person lost no weight on the scale that week, they lost centimeters around their waist and that is far more important to your health. 

BMI--I am a BMI Basher.  The BMI, short for Body Mass Index, is an index used to measure our health risk by calculating height and weight.   It was devised between 1830 and is defined as the individual's body mass divided by the square of his or her height. The formula universally used in medicine produces a unit of measure of one’s weight in kilograms divided by their height in meters, squared.  In 1927, the BMI became a main measure of evaluation of one’s body mass.  For the last 25 years, it has been used by most health providers and doctors to assess their patient’s health risks vis-à-vis their weight.  When you read the all too frightening statistics about how much of the population is overweight and obese, these are based on BMI readings.  Here is how we interpret BMI results:

BMI	Weight Status
Below 18.5	Underweight
18.5 – 24.9	Normal
25.0 – 29.9	Overweight
30.0 and Above	Obese

The BMI is very easy to use, and that is one of the reasons that doctors like to use it.  It is simply using height and weight measurements which are relatively easy to obtain.  But the accuracy of the BMI  in terms of measuring overall health risk is questionable.

A 2010 study that followed 11,000 subjects for up to eight years concluded that BMI is not a good measure for the risk of heart attack, stroke or death. A better measure was found to be the waist-to-height ratio.

BMI is particularly inaccurate for people who are fit or athletic, as the higher muscle mass tends to put them in the "overweight" category by BMI, even though their body fat percentages frequently fall in the 10-15% category, which is below that of a more sedentary person of average build who has a "healthy" BMI number. Body composition for athletes is often better calculated using measures of body fat, as determined by such techniques as skin fold measurements or underwater weighing and the limitations of manual measurement have also led to new, alternative methods to measure obesity, such as the body volume index.

BMI also does not account for body frame size; a person may have a small frame and be carrying too much excess fat, but their BMI reflects that they are "healthy". Conversely, a large framed individual may be quite healthy with a fairly low body fat percentage, but be classified as "overweight" by BMI.  A further limitation of BMI relates to loss of height through aging. In this situation, BMI will increase without any corresponding increase in weight.

But to put it in simple terms, the BMI doesn’t measure important aspects of healthy living.  There is no calculation that includes how much exercise a person does or whether or not you include healthful foods in your diet.  A person with a 22-23 BMI may look good in the eye of the examining doctor, however, if this person happens to have a fast metabolism, eats unhealthy food and doesn’t exercise, he may be a lot less healthy and much more at risk for sickness and mortality than a person with a 27-28 BMI who exercises daily and tries to consume healthy foods. 

There is no question that the BMI can be an important calculation to help us have an idea of how our health is affected by our weight, but unlike the impression given by our public health officials, it is certainly not the beginning and end all of measurements related to our weight and health.  As I advise my clients all the time, if you need to lose weight, every pound and kilo that you lose is a pound or kilo improvement in your health and if your weight loss is coupled with doing even minimal exercise, then in spite of a BMI that may be higher than 25, you are doing wonders for your health.  The best measure of how you are doing is probably more how your clothes are fitting than anything else, because that is the best indication of fat-weight loss.  The BMI is probably heading the way of the original food pyramid which did more harm than good to the public health.  New and more accurate measures, that are not difficult to use, are on the way.

Your weight and BMI are important, but they are not the bottom line in assessing your health risk. If you keep doing what you need to in terms of proper eating and exercise, you will be doing wonders for your health.  Keeping your weight in check and exercising daily will “add hours to your day, days to your year, and years to your life.” 

Alan Freishtat is an A.C.E. CERTIFIED PERSONAL TRAINER and a LIFESTYLE FITNESS COACH with over 16 years of professional experience. He is the co-director of the Jerusalem-based weight loss and stress reduction center Lose It! along with Linda Holtz M.Sc. and is available for private consultations, assessments and personalized workout programs. Alan also lectures and gives seminars and workshops. He can be reached at 02-651-8502 or 050-555-7175, or by email at alan@loseit.co.il  Check out the Lose It! web site - www.loseit.co.il    US Line: 516-568-5027