Visceral fat is the fat around the abdominal organs. Because such fat is under the abdominal muscles, it cannot be detected by pinching the skin over the abdomen. In contrast, subcutaneous fat is located right under the skin and can be detected by a pinch and quantified by using a skinfold-caliper. Unfortunately, visceral fat is the most dangerous kind in that it produces hormones and inflammatory agents. Framingham heart study researchers reported that visceral rather than subcutaneous fat was associated with an indicator of cholesterol deposits in the aorta, the body's main artery.
Fortunately, exercise can have an impact on visceral fat. A study by Gary Hunter Ph.D., of the University of Alabama at Birmingham, showed that, among a group of women who lost an average of 24 lb by dieting, only those who stuck to an aerobic or strength-training exercise program of 40 minutes, twice a week, managed to keep off all of the visceral fat they lost. Those who did not exercise or who quit their exercise programs increased their visceral fat an average of 33% in the year following their weight loss.