Is Body Mass Index or BMI a Reliable Measurement for Weight Loss Programs?

If you are into weight loss programs and diet plans, you probably have run into the term BMI or Body Mass Index. It is the ratio of your weight to your height. It is computed by dividing your weight (in Kilograms) by your height (in meters²). I am now 79 kilograms and I'm 1.70 meters tall. So that's 79 / (1.7) ² therefore my BMI is 27.34 (nice improvement from a BMI of 42.56 two years ago). Since my BMI is over 25, I'm considered overweight. However, is it reliable to base your fitness level using BMI? Does this mean that I'm not fit or am I just simply overweight?

Well, in my point of view, BMI is probably an ideal but not necessarily an accurate basis of a person's fitness level since it basically considers the weight of a person relative to his or her height alone. However, there are several other factors that can affect the computation of the Body Mass Index and if your BMI falls under a certain category it doesn't always mean that you really are in that category's fitness level.

Come to think of it, we have different body orientations. Some of us have long and big bones which can add up to the weight or vice versa. Muscles are heavier than fat and a body builder may be heavier than his/her ideal weight based on a BMI computation but he/she could very well be healthy. We also have to consider persons with disability. They may not have arms or legs but a lot of them are very inspiring and are leading happy and very healthy lives.

And of course, we should also consider several medical conditions especially those that affect height and weight. Dwarfism and Gigantism may generate a BMI that doesn't actually reflect the person's fitness. He/she may also be very healthy. The same goes for pregnant women. This may be naive but if you get the BMI of the mother, with that extra weight from the baby, you really can't say if she's healthy or not.

Lifestyle comes into play as well. A person with a BMI of 23, which is just right based on the charts, may not be as healthy as someone who has a BMI of 27. The former may be smoking, drinking, using illegal medications, etc. but the latter may be eating healthy foods, sleeping well and based from that, the latter that has a BMI of 27 may actually be healthier and has lesser risk of having illnesses relating to lifestyle such as hypertension, stroke and heart attack.

I asked our family doctor when I started working out a couple of years ago if I can rely on BMI to measure my overall fitness. He told me that, it's fine since Body Mass Index may actually indicate your fitness level and he had the same point of view as I am. He also said that as your weight goes down, so does your BMI. It is just the ideal proportion between height and weight and is what a lot people use as a basis.

The question I guess is, "Can you use BMI as a measurement guideline for your weight loss program?" My answer would be yes. Regardless of your body's orientation, the computation of the BMI will be relative. As you lose those extra pounds, your BMI will definitely go down since your height will most likely be the same. You can even use BMI as part of your goals. I am using BMI in my weight loss program and I can see my BMI going down significantly. I'm actually targeting a BMI of 25 and a few more pounds. In a month or two, I'll most likely be able to reach that goal.

Source:

Dr. Ramon A. Reyes M.D., Internal Medicine - Cardiologist
St. Luke's Medical Center, Philippines

Wikipedia - Body mass index
http://en.wikipedia.org/wiki/Body_mass_index