What's Your Body Mass Index? What Does It Mean?

One term we hear a lot about recently is "Body Mass Index", or BMI. It seems to be important, but many people are not sure what it is, what it means, or why they should be concerned about it. In this small article, we are going to try to shed a little light on:

1. What is Body Mass Index?

2. How is it calculated?

3. What does it mean?

Stated simply, your body mass index is a means of measuring your body fat relative to height. The basic reason for this is that weight alone is not a reasonable measure of fat or health. For years, men and women have looked at height/weight tables and been told that if they were of a certain height and weighed a certain weight than they were "overweight" and, by implication, in some sort of potential health crisis. However, the BMI calculation allows an individual or health care provider a means of making a quick assessment of potential health risks.

Calculating your Body Mass Index is a relatively simple process. You can calculate your BMI yourself, but you are more likely to get a more precise measurement of your health risk if you have it and other measurements done by your doctor or at a facility which has the necessary equipment and professionally trained personnel.

To calculate your BMI based on height and weight, divide your weight in pounds by your height in inches squared and multiply that answer by 703. If you are using the metric system, the weight will be in kilograms, and the height will be measured in meters. The equation is exactly the same (remember to square your height), but there is no need to multiply by 703.

However, the results still only involve height and weight and do not take other factors into account. For example: A muscular, weightlifting athlete in excellent health, i.e. someone like Arnold Schwarzenegger, would appear to be overweight.

While calculating a person's BMI is simple and immediately gives a health care professional an idea of the individual's potential health risks relevant to the fat on their body, there are still some other factors which should be assessed as well. The athlete mentioned above might have a very small waist, and indeed, the circumference of the waist should also be taken in addition to the BMI calculation itself. It is also possible to take some fairly specific fat measurements using calipers and other instruments. It is also important to view the BMI in the context of the individual's health history, life style, age, sex, smoking, drinking, and other factors. That is why having these measurements done by trained professionals is important.

For the moment, however, let's just look at our Body Mass Index measurements and see what they mean.

• A BMI of 18.5 is considered as being Underweight.
• A BMI range of 18.5 – 24.9 is considered normal.
• A BMI range of 25.0 – 29.9 is defined as overweight.
• A BMI of 30.0 and above is categorized as obese.

While a little too complicated to reproduce in an article which may be published on many different sites, there are charts available online which will allow you to add such measurements as waist circumference to the Body Mass Index calculation in order to get a slightly more accurate assessment of health risk due to being overweight or obese. A rule of thumb however, is that for men a waist circumference of more than 40 inches raises the health risk. For women, a waist circumference of more than 35 inches also raises the risk.

So, what does a high BMI mean in terms of potential health risks?

While there is no guarantee that obesity or an overweight condition in any one individual will definitely result in specific conditions, it has been statistically shown that there is a correlation between being overweight or obese, and the likelihood of incurring one or more of these conditions as a direct or indirect result:

• High blood pressure,
• High cholesterol
• Type II diabetes
• Heart Disease
• Some forms of cancer

The good news is, that should you find yourself defined as overweight or obese, a weight loss of just 10% of your current weight will have a definite impact on the health risks you face.

The best way to control your weight and minimize health risks due to obesity or being overweight is through regular moderate exercise and by making wise nutritional choices. Additionally, a lifestyle which includes regular exercise and healthy eating choices will produce other positive health changes in addition to the weight loss itself. Fad diets do not work for permanent healthy weight loss, and diet pills and potions are at best ineffective and can actually be dangerous in some cases. Some diet regimens may actually result in increased weight and a higher BMI in the long run.

In order to improve your health outlook, take a look at your BMI and use it as a reminder of the choices you need to make in order to live a longer and healthier life.