BMI Explanation

A healthy BMI is obtained through healthy eating.

BMI, or body mass index, is a numeric value that is calculated using an individual's height and weight. The value provides an approximation of an individual's fat content and categorizes them into weight categories. Health care providers use BMI as a tool to determine risk for disease.

Categories

For adults, once BMI is evaluated, the number is categorized into one of four, or sometimes five, groups. A value less than 18.5 is underweight; a value between 18.5 and 24.9 is normal; a value from 25.0 to 29.9 is overweight; and a value exceeding 30.0 is obese. A fifth category is sometimes used in extreme situations: a value of more than 40.0 is morbidly obese.

Limits

Measuring BMI does have limitations, such as overestimating body fat in an athlete with a muscular build and underestimating body fat in an older individual who has lost muscle. Health care providers often use BMI in conjunction with waist circumference and family history of chronic illness to evaluate a patient's weight and health risks.

Considerations

According to the Centers for Disease Control and Prevention, a BMI of 25 or higher shows significantly increased risk of chronic diseases, such as heart disease, diabetes and high blood pressure. A person with a BMI exceeding 25 and family history of chronic disease should be especially diligent about losing weight. Even losing 10 percent of your body weight can significantly lower your risk for chronic disease.

References

• Centers for Disease Control and Prevention: Body Mass Index
• National Heart Blood and Lung Institute: Assessing Your Weight and Health Risk