A study published in the Journal of the American Medical Association (JAMA) provides new evidence suggesting that mildly overweight people live longer than those who are too thin. However, body shape -- not weight -- is the single most powerful predictor of women's future health, according to women's health expert Dr. Marie Savard, who draws on extensive research in her new book, Apples & Pears: The Body Shape Solution to Weight Loss and Wellness. Dr. Savard noted that body shape was not included in the JAMA study's analysis.

"Apple-shaped women -- who gain weight around their middle -- are more likely to develop disorders like heart disease, diabetes and breast cancer. Pear-shaped women -- who add pounds around their hips, buttocks and thighs -- are more susceptible to problems like osteoporosis," said Dr. Savard.

Gut or butt? Why does it matter? According to Dr. Savard, it all boils down to where we store our excess fat. Fat stored within the abdomen is a hormone and chemical powerhouse that can lead to increased risk of serious medical disorders. Excess fat stored in the "pear area" is actually protective.

"Women need to throw away the scale and dig out the tape measures in order to better measure health risks and get a jumpstart on preventing them," suggests Dr. Savard. "By knowing if they are an apple or a pear, women can make smarter decisions about their diet, exercise and other health strategies, including which medical tests they need by the time they turn 40. The first step is to discuss their body shape with their doctor -- even bring a tape measure to their next appointment."

To determine body shape: measure around the narrowest part of your waist to determine your waist circumference. Then measure around your hips -- about three or four inches below your pelvis bone. Divide your waist circumference by your hip measurement to get your waist-to-hip ratio, or WHR. A WHR higher than 0.80 means you are apple-shaped.

Apples & Pears author Dr. Marie Savard is a nationally-known internist, women's health expert and advocate for patients' rights. She is the award-winning author of How to Save Your Own Life and the creator of The Savard Health Record. She lives in Philadelphia.

* * * Marie Savard is also a regular contributor here at the Thyroid site. Click here to read her articles and interviews.