For many years, the experts, including our government have been telling Americans that obesity is a leading cause of preventable deaths. For example, as recently as January, the Center for Disease Control (CDC) ranked obesity as the second leading cause of preventable death, and estimated that about 365,000 Americans died as the result of obesity every year.

Now, however, the CDC has announced that obesity accounts for only about 25,814 deaths a year in the United States. So, what has caused the CDC to give a figure (365,000) that's nearly 14 times higher than the now estimated 25,814?

And just how did the Center for Disease Control overestimate the problem by nearly 340,000 deaths?

Obesity being extremely overweight can definitely be lethal. However, several smaller studies suggest that people who are just modestly overweight have a lower risk of death than those whose weight is considered normal.

One of the problems is that normal may be set too low for today's Americans. Also, it is thought that Americans who are classified as overweight are eating better, exercising more and doing a better job of managing their blood pressure.

Obesity is generally defined using a measurement called Body Mass Index (BMI). It is calculated by dividing a person's weight x 703 divided by their height squared or

BMI = Weight (lbs) x 703
Height squared (in2)

This means a woman weighing 173 lbs who is 5'6 would have a BMI of 28, making her overweight but not obese.

The error was created by the fact that the majority of the 400,000 deaths came from a definition of "obese" as a BMI 30 or higher. However, a substantial minority came from the "overweight" group of those with a BMI 25 to 29.9. Besides, the study failed to show a statistically significant relationship between being merely "overweight" and increased risk of death. So, if the deaths of overweight people had been excluded, the study would have reported 17 percent fewer deaths.

For that matter, the results of this study seemed indicate that being overweight could have a protective effect. In fact, most studies find no correlation between being overweight and an increased risk of death.

A new study attributes only 111,909 deaths per year to obesity, and subtracts the benefits of being modestly overweight, to arrive at the 25,814 figure.

What does all this mean to the typical American? It means it's a good idea know your BMI as it can be used as an indicator of coming problems. If your BMI is between 18 and 24.9 your weight is normal. If your BMI is 25 to 29.9, you are overweight. If it is 30 to 34.9, you are obese with a high risk of problems such as heart disease, diabetes and high blood pressure. A range of 35 to 39.9 puts you in the obese category with a very high risk of disease. And any BMI greater than 40 makes you extremely obese with an extremely high risk of disease.

For that matter, some estimates are that a BMI of 30 or higher increases the risk of death from any cause by 50% to 150%.

What can you do if you are in one of the at-risk categories? It's pretty simple. Lose weight. You can do this by cutting back in the foods you eat and by exercising more. The US Department of Agriculture (USDA) has just announced new food pyramids based on a person's age, sex and amount of exercise. You can find your pyramid by going to mypryamid.gov. Put in your age, for example, 40, the fact that youre a male, and that you exercise less than 30 minutes per day. Click on Submit, and you will see a food pyramided geared specifically to help you eat healthy. Follow these guidelines for a few months and youre bound to see a new, healthier, thinner you.