There's been criticism about using BMI (body mass index) to determine if a person is obese or overweight, and to predict how it might indicate risks to health and longevity. After all, the weight of a super-muscular body may register as "obese" when the percentage of body fat may be extremely low.

And now a study published in the Annals of Family Medicine reveals that your BMI also fails to predict your risk of future heart issues or death.

What does do the job?

Well, there's the traditional (and still accurate) measure of your waist size in relation to your height. You want your waist to measure less than half your height. If it's larger than that, you're carrying around excess fat.

You can also obtain a direct measure of your body fat using a bioelectric impedance device that evaluates the resistance of your body tissue to a small electrical current.

Tracking people ages 20-49 for 15 years, researchers found that if that reading indicates a person has a high level of body fat, they're 78% more likely to die from any cause and 350% more likely to die from heart disease than folks with a healthy body-fat level.

Using a person's BMI to figure out their risks didn't accurately predict anything.

Check your waist vs. height measurement and ask your doctor about getting a bioelectric impedance analysis.

If you are carrying excess body fat, discuss lifestyle and medical weight-loss options.