Body Mass Index

Body Mass Index


The Body Mass Index or BMI

is another important tool to help ascertain how overfat you are. Sometimes the BMI can be misleading. For example, a 240-pound bodybuilder who is 5 feet 11 inches would have a BMI of 34, which would appear to put him in the very highest risk category. But if that same person has only 8 percent body fat, this changes the entire story. However, for most readers of this book, a high BMI will be a red flag predicting many health risks. For example, a recent study published by the American College of Sports Medicine has shown a direct correlation between a high BMI and increased levels of C-reactive protein. High CRP is an accurate indicator of inflammation in the body, which increases the risk of a first cardiac event (heart attack), even after adjustments have been made for risk factors such as age, smoking, and body weight.

Exercise and increased levels of physical activity, which result in weight loss and lowered BMI, have been shown to reduce a person’s level of CRP. So while the BMI is not an infallible standard by which to measure how fat you are, taken together with other factors it is a useful tool for helping to create an accurate health profile and can serve as an early warning system for heart disease. 

BMI is defined as your weight in kilograms divided by your height in meters squared. To save you the trouble of converting pounds to kilograms and inches to meters, I have done the math for you. Simply look up your BMI in the chart provided. Your height can be found in the left-hand column and your weight (in pounds) runs along the top of the chart. Your BMI is where both points intersect. Because people between 5 feet and 5 feet 2 inches tall generally have a lighter frame, we have included a different chart for them.

Interpret Your BMI

  • If your BMI is below 20. Unless you are an athlete with a very high ratio of lean muscle–to–body fat, a BMI this low might mean that you are too thin and are possibly compromising your immune system.
  • If your BMI is between 20 and 22. This range is associated with living the longest and having the lowest incidence of serious illness.
  • If your BMI is between 23 and 25. These numbers are still within the acceptable range and are associated with good health.
  • If your BMI is between 26 and 30. Now you are entering the zone where there are serious health risks. A BMI this high puts you at risk for developing heart disease, stroke, type 2 diabetes, and some kinds of cancers. You should definitely lower your weight through diet and exercise.
  • If your BMI is over 30. This is the worst-case scenario where you are definitely putting yourself at risk for all of the diseases mentionedabove. It is imperative that you begin to lose weight and exercise.