The study, published in the American Journal of Clinical Nutrition, determined a diet using either whole grains -- whole-wheat flour, bulgur, oatmeal -- or refined grains -- white flour, white bread, white rice -- resulted in significant decreases in waist circumference and in body weight.

Both groups of 25 obese men and 25 obese women lost between 8 to 11 pounds on average, but weight loss in the abdominal region was significantly greater in the whole-grain group.

Lead author Heather Katcher, a Pennsylvania State University doctorate recipient and now at Tulane University, also found those eating whole grains experienced a 38 percent decrease in C-reactive protein levels in their blood. High levels of this inflammatory marker have been linked to a higher risk for diabetes, hypertension and cardiovascular disease.

All 50 participants were asked to consume five servings of fruits and vegetables, three servings of low-fat dairy foods, and two servings of lean meat, fish, or poultry daily for a 12-week period.