by Nicholas Bacon

Created on: May 03, 2009   Last Updated: May 11, 2009

What is BMI? Many people know that it has something to do with your weight and health, but not as many have a comprehensive understanding of BMI. In order to grasp the effects BMI has on your health we must first discuss what it means.

BMI stands for Body Mass Index. Body Mass Index is a number derived from a formula based on a person's height and weight that is used to measure the amount of fat a person has on their body. Although BMI may not always be an entirely accurate measurement it is considered by the CDC (Centers for Diseases Control and Prevention) to be a reliable alternative to other forms of direct body fat measurement.

BMI is a popular tool used by professionals and non-professionals due to its simplicity and low or no expense. In order to determine your BMI all you need to know is your height in inches and weight in pounds. The simple formula is: weight/ (height in inches)2 x 703. For an example we will use John. John is a 6'2" male who weighs 200 pounds.

- First John would need to figure out his height in inches is 74.

- John would then have to square his height of 74. Therefore 74 x 74 is 5,476

- Now John can divide his weight by his height in inches squared. Therefore 200/5,476 is equal to about 0.0365

- Lastly we will multiply 0.0365 by 703.
Therefore 0.0365 x 703 is equal to about 25.66.

Once your BMI is calculated you must then compare your final number to a scale. This scale was created in an attempt to categorize a person's BMI as underweight, normal, overweight, or obese. These definitions were based on studies that have shown that health risks increase greatly in persons with a BMI of 25 or greater.

- Persons with a BMI below 18.5 are categorized as underweight.

- Persons with a BMI between 18.5 and 24.9 are categorized as normal.

- Persons with a BMI between 25.0 and 29.9 are categorized as overweight.

- Persons with a BMI 30.0 and above are categorized as obese.

Therefore according to this scale John would be considered overweight.

An important detail to note is that BMI itself does not diagnose any sort of health risks or problems. It is used purely as a measurement tool and to determine the possibility of risks and problems. Once a health professional has found that your BMI is high, there are other tests and evaluations that are used to determine if you are at risk for or have health problems. A high BMI does not always mean you are unhealthy. For example John, who is considered overweight by the BMI scale, may be in very good physical condition. In his case his BMI may be due to a higher muscle mass as opposed to fat.

What are some of the health risks and problems that can occur due to being overweight and obese?

- Hypertension (high blood pressure) which can cause many other issues including damage to the arteries, heart, brain, kidneys and eyes.

- High cholesterol

- Type 2 diabetes

- Heart disease

- Stroke

- Gallbladder disease

- Osteoarthritis

- Sleep apnea and respiratory problems

- Endometrial, breast, and colon cancers

The BMI test has been found to be a reliable, accurate and simple way to assess the possibilities of the risk of health problems due to excess body fat.
However, every person's body is different and therefore it is best to have these risks fully evaluated by a medical professional.

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