Storing fat primarily in your belly increases your chances of suffering heart attacks and diabetes. People who store fat primarily in their bellies are called "apples", while those who store fat primarily in their hips are called "pears". The apples have higher blood insulin and sugar levels that raise levels of the bad LDL cholesterol that causes heart attacks, and lower levels of the good HDL cholesterol that prevents heart attacks.

Fat cells in your belly are different from those on your hips. The blood that flows from belly fat goes directly to your liver, while the blood that flows from your hips goes into your general circulation. The livers of those who store fat in their bellies are blocked from removing insulin by the extra fat, so they do not remove insulin from the bloodstream as effectively as the livers of people who store fat primarily in their hips.

A study from Denmark shows why having a fat belly and elevated triglycerides markedly increases your chances of suffering a heart attack (Circulation, Volume 111, 2005.) Your body makes triglycerides from sugar. Abdominal obesity comes from high blood insulin levels. When you eat, your blood sugar level rises. To prevent blood sugar levels from rising too high, your pancreas releases insulin, which converts blood sugar to a type of fat called triglyceride. Insulin also drives triglycerides into the fat cells in your belly. So having high triglycerides and a fat belly are signs of high blood insulin levels, and high blood levels of insulin constrict arteries to cause heart attacks.

If you store fat primarily in your belly you should restrict refined carbohydrates found in foods made with flour, white rice or milled corn, and all added sugars.

Sit-ups are fine for strengthening your belly muscles, but don't believe they will get rid of a fat stomach. Exercising a muscle does not get rid of fat over the specific muscles that are exercised. If it did, tennis players would have less fat in their tennis arms, but they don't. The only way to reduce a fat belly is to lose weight overall.

Gabe Mirkin, M.D.

Dr. Gabe Mirkin has been a radio talk show host for 25 years and practicing physician for more than 40 years; he is board certified in Sports Medicine and three other specialties.

Dr. Mirkin's daily features on fitness have been heard on CBS Radio News stations since the 1970's. He has written 16 books including The Sportsmedicine Book, the best-selling book on the subject that has been translated into many languages. His latest book is The Healthy Heart Miracle, published by HarperCollins.

Dr. Mirkin is a graduate of Harvard University and Baylor University College of Medicine. A Boston native, Dr. Mirkin did his residency at the Massachusetts General Hospital. He has served as a Teaching Fellow at Johns Hopkins Medical School, Assistant Professor at the University of Maryland, and Associate Clinical Professor in Pediatrics at the Georgetown University School of Medicine. He has run more than forty marathons and is now a serious tandem bicycle rider with his wife, nutritionist Diana Mirkin.