What is Body Mass Index (BMI)?

BMI is a guideline that uses your weight and height to figure out whether you are at risk for weight-related health problems. BMI reflects body mass instead of body fat and is used to screen for health or nutritional disorders. For an individual, other data must be used to figure out whether a high BMI is linked to disease and death.

The relationship between fatness and BMI is influenced by age and gender. For example, women have more body fat than men at the same BMI and older people have more body fat than younger people at the same BMI.

BMI Categories

Limits to BMI

For most people, BMI provides a good measure of obesity. However, BMI leaves out a lot of relevant information including activity level, muscle mass, and percent body fat. It may overestimate body fat in athletes and others who have a muscular build or it may underestimate body fat in older persons and others who have lost muscle mass.

For the most accurate and personalized information on your body type and how to achieve a BMI that is right for you, consult with a registered dietitian, physician or health professional.

Why is BMI Important

BMI is used to evaluate if a person is at an unhealthy weight. If your BMI is high, you may have an increased risk of developing certain diseases, including

• High blood pressure
• Cardiovascular disease
• Diabetes
• Osteoarthritis
• Cancer

Other risk factors to consider that increase your chances of developing these diseases include:

• High LDL-cholesterol (this is the bad cholesterol)
• Low HDL-cholesterol (this is the good cholesterol)
• High triglycerides
• High blood sugar
• Family history of premature heart disease
• Physical activity
• Cigarette smoking

What Do These Numbers Mean?

Weight loss is recommended for adults who are obese and for adults who are overweight who have other risk factors. Even a small weight loss will help to lower your risk of developing diseases associated with obesity. Talk to your doctor to see if you are at an increased risk and if you should lose weight. Your doctor will evaluate your BMI and other risk factors for heart disease.