Body Fat Index (BMI) provides vital information about the possible state of your health and body metabolism. BMI has been the medical standard for obesity measurement since the early 1980's when government researchers developed it to take height into account in weight measurement.
Body Mass Index = Weight(kg) / Height(m)^2
BMI is a reliable indicator of total body fat, which is related to the risk of disease and death. The score is valid for both men and women but it does have some limits. The limits are:
- It may overestimate body fat in athletes and others who have a muscular build.
- It may underestimate body fat in older persons and others who have lost muscle mass.
Critical health risks may begin with a BMI of 25. Researchers say that, as BMI increases, blood pressure and total cholesterol levels also rise, along with the increased possibility of serious illnesses such as diabetes, heart disease, breast cancer, prostate cancer, colon cancer, and several other debilitating life-threatening diseases.
According to the National Health and Nutrition Examination Survey
Overweight is BMI of:
- 26 to 27.8 for men
- 26 to 27.3 for women
Obesity is a BMI of over:
- 27.8 for men
- 227.3 for women
30 and over is definitely obese for both genders
According to the National Academy of Sciences' diet and health report
- 22 to 27 BMI for persons 45 to 54 years of age
- 23 to 28 BMI for persons 55 to 65 years of age
- 24 to 29 BMI for persons over 65 years of age
According to the National Health and Nutrition Examination Survey of 1994
- 59% of American men and 49% of women have BMI's over 25.
- Extreme obesity (BMI of 40 or more) was found in 2% of the men and 4% of the women.
Another way to determine body fat is using your waist circumference
Determine your waist circumference by placing a measuring tape snugly around your waist. It is a good indicator of your abdominal fat, which is another predictor of your risk for developing risk factors for heart disease and other diseases. This risk increases with a waist measurement of over 40 inches in men and over 35 inches in women
Other Risk Factors
Besides being overweight or obese, there are additional risk factors to consider.
- High blood pressure (hypertension)
- High LDL-cholesterol ("bad" cholesterol)
- Low HDL-cholesterol ("good" cholesterol)
- High triglycerides
- High blood glucose (sugar)
- Family history of premature heart disease
- Physical inactivity
- Cigarette smoking
A 2005 study published in Lancet found that a waist-to-hip ratio is a better predictor of heart attack than the BMI. A waist-to-hip ratio (waist measurement divided by hip measurement) below 0.085 for women or 0.09 for men is average. Anything above that increases the risk for heart disease.