Body mass index (BMI) is a number derived from an individual's weight and height. It is one way to determine body composition (amount of body fat.) The medical community uses this number as an indicator of health. There is not a specific or ideal weight that applies to people of a certain height. Though there are advantages and disadvantages to using the BMI method, it will provide a general guideline for how much you should weigh.
Significance
According to the 2009 report, "F as in Fat: How Obesity Policies are Failing in America," 66 percent of adults are overweight or obese. Obesity rates are expected to rise in 2010. Controlling your weight is important considering more than one-quarter of health care costs are related to obesity. Diseases that are related to obesity include heart disease, stroke, type 2 diabetes and hypertension.
Classification
BMI is classified in four categories: underweight, normal weight, overweight and obesity. A BMI of less than 18.5 falls into the underweight category. When your BMI is between 18.5 to 24.9, you are considered "normal weight." BMI in the range 25.0 to 29.9 is classified as overweight. A BMI greater than 30 is deemed as obese. If you are outside of the normal weight category, the addition or loss of a few pounds usually brings your BMI into the desirable range.
Advantages
BMI is widely used due to its correlation to level of body fat. It is a good predictor for risk of developing a variety of health problems. As such, it is found on health history questionnaires both in the gym and the doctor's office. It is quick and easy to determine your BMI by using web-based calculators.
Disadvantages
The major disadvantage to using BMI is that it does not account for different body types. A person who has well-developed muscles and low body fat could be classified as overweight. This is due to the fact that gross weight is used in the calculation. Therefore, BMI should be used in conjunction with other body composition assessments such as percentage of body fat.
Prevention/Solution
Carrying extra weight can be detrimental to your health. Though body weight is influenced by genetics, the best way to prevent weight gain is to lead a healthy lifestyle that includes regular exercise and nutritious eating. A 5 to 10 percent reduction in total weight can improve health. The journal, "Medicine & Science in Sports & Exercise" states, "The most successful studies in terms of weight loss have been those that combined diet and exercise to optimize the energy deficit."
References
- Healthy Americans: "F as in Fat: How Obesity Policies are Failing in America;" 2009
- Ace Fitness: American Council on Exercise BMI Calculator
- "Medicine & Science in Sports & Exercise"; ACSM Position Stand: The Recommended Quantity and Quality of Exercise for Developing and Maintaining Cardiorespiratory and Muscular Fitness, and Flexibility in Healthy Adults; June 1998
Member Comments