Normal Weight Obese: How Thin Can Still Be Fat

Just when you thought that losing a significant amount of weight was the end goal -- enough to improve your overall health and keeping you looking svelte -- a Mayo Clinic study reveals that people considered "average" weight can still be considered "obese."

According to Mayo Clinic research reported by ABC News, as many as 30 million Americans considered average weight may have "normal weight obesity." That means a higher risk of obesity-related diseases, such diabetes, high cholesterol and heart disease. Yikes!

"The concept of normal weight obesity isn't necessarily new," said Marisa Moore, registered dietitian and spokesperson for the American Dietetics Association. "You can have a normal BMI and appear to be slim, which makes people think that they are at less risk for things like heart disease."

The study's research lead, Dr. Francisco Lopez Jimenez, followed 6,171 Americans over nine years, and found that 20 to 30 percent of people considered "normal" weight and BMIs have a surprisingly high ratio of body fat to lean muscle. These findings, published in November 2009 in "European Heart Journal," suggest that reducing heart risk requires increasing the percentage of lean muscle mass at the expense of body fat.

Translation: losing weight is not enough, and exercise -- particularly weight lifting and resistance training -- is an integral part in maintaining cardiovascular health and building lean body mass.
Moore said that a primary factor in determining whether you are a healthy weight or "normal obese" is making sure that you're are looking at an overall picture. "I think your midsection is a great place to start," she said, "since extra weight in this area can be a marker for heart disease."

She suggests measuring your waist circumference for an accurate measure of body fat. For women, this number should be less than 35 inches, and for men it should clock in at less than 40. According to the Mayo Clinic, women should have a body fat percentage below 30 percent, while men should have a fat to muscle ratio of less than 20 to 25 percent.

Of course, Moore is also a proponent of maintaining an active lifestyle and healthy diet if you're not already. "Even if you have a normal BMI," she said, "if you're not active or eat whatever you want, then you might want to go further."

Interested in calculating your body mass index? Here's why it shouldn't be the only factor you use to determine your weight range.