Visceral fat accumulates inside the abdomen, often surrounding the internal organs, including the heart, liver, kidneys and intestines. This type of fat accumulates around the middle and is associated with a large belly and waist circumference. However, waist size isn’t an exact correlation with visceral fat because it’s hidden deep inside the body. Gary Hunter, Ph.D., Exercise Physiologist with the University of Alabama at Birmingham, says the only way to see how much visceral fat is in the body is to do a CT or MRI scan.
Researchers say visceral fat cells are very active. They release fatty acids into the blood and promote inflammation. Visceral fat is associated with a reduced sensitivity to insulin (the hormone that enables the body to use glucose for fuel), a risk factor for development of type 2 diabetes. Visceral fat deposits are also associated with elevated triglycerides, higher LDL levels (the “bad” cholesterol), low HDL levels (the “good” cholesterol), high blood pressure, cardiovascular disease and death from all causes.
Reducing Visceral Fat in Women
Hunter says as we grow older, we tend to put on more visceral fat. Between 25 and 65, the amount of visceral fat on a woman’s body almost quadruples. Researchers at the University of Alabama at Birmingham wanted to see if diet and exercise had any effect on visceral fat loss in pre-menopausal women with a BMI of between 27 and 30 (overweight, but not obese). All the women were given a CT scan to measure visceral fat levels. Participants were then put on a weight loss diet and randomly assigned to one of three exercise groups: resistance exercise, aerobic exercise or no exercise.
After one year, all the women lost weight, bringing their BMI down to normal levels (less than 25). CT scans also showed nearly equal changes in visceral fat loss among the three groups.
The researchers then followed the women for another year. During that second year, participants in the aerobic and resistance exercise groups gained back an average of seven pounds. However, they didn’t regain any visceral fat. On the other hand, the non-exercisers gained more weight, an average of 12 to 15 pounds, and put on a significant amount of visceral fat.
The study results show how important exercise is for preventing the accumulation of visceral fat. Hunter says resistance training slows down muscle loss associated with aging. Muscles burn more calories than other tissues. So the more muscle mass a person can maintain, the fewer calories that are going to be stored as fat. Aerobic exercise also helps burn extra calories and improves the body’s sensitivity to insulin.