Know thyself. It was the philosophical underpinning of ancient Greek culture.

Know thy fat—a variation on the same theme—has particular application to our times.

There are two kinds of fat lurking beneath your skin. Learning to distinguish between subcutaneous and visceral fat is a vital first step along the path to good health.

Visceral fat gathers around the organs deep inside the abdomen. Subcutaneous fat lies close to the surface, just below the skin.

Knowing what makes them different from each other provides fresh insight into the nature of disease, since many illnesses are associated with visceral fat.

“It has more inflammatory markers than subcutaneous fat,” says Dr. Nir Barzilai, director of the Institute for Aging Research at the Albert Einstein College of Medicine in New York.

“Inflammatory markers are important in the development of diabetes and arthritis. When we examine visceral and subcutaneous fat, we find important biological differences between the two. Over 200 proteins are altered in one compared to the other. The differences point to visceral fat being more problematic. For example, if you have significant amounts of visceral fat, your blood will clot easier.”

It’s also been identified with insulin resistance and cardiovascular disease.

Weight gain results in the accumulation of both fats, however, as we age the distribution of fat changes and our levels of visceral fat increase. Dr.Barzilai suspects the problem may be caused by a decline in growth hormone.

Interestingly, women are subject to varied patterns of fat distribution throughout adulthood.

“Women experience two stages,” explains Dr. Barzilai. “They accumulate visceral fat after pregnancy, and then again during menopause. In both cases the onset is dramatic. With men it’s a little more gradual. We need to acknowledge that obesity is a risk factor in older people. Older individuals have more visceral fat. Even those who are lean can appear pregnant sometimes. This is an alteration with aging, and we’re interested in finding the reason for it, and to see if we can prevent it with drug therapy.”

Dr. Barzilai points to shortcomings in the Body Mass Index (BMI), arguing that it fails to address the issue of fat distribution. When doctors examine their patient’s BMI, they are unlikely to consider visceral fat. This is particularly true in respect to the elderly, whose health cannot be accurately accessed by calculating their BMI.

“People need to be more aware of abdominal obesity,” says Dr.Barzilai. “And the only way to deal with it is to exercise. Strive to be leaner. My advice is to be lean and exercise; that is the only way to modulate abdominal fat. I¹m afraid there is nothing else we can do.”

On a hopeful note, a study conducted by Duke University Medical Center in Durham, North Carolina, has determined that a moderate amount of exercise is enough to reduce visceral fat. More notable perhaps was how rapidly visceral fat accumulates when people are inactive.

Test subjects who remained sedentary increased their level of visceral fat by approximately eight-and-a-half per cent over a period of eight months. Conversely, visceral fat decreased slightly more than eight per cent in those who performed the most exercise.

According to researchers, just 17 miles of jogging each week will significantly reduce visceral fat and subcutaneous abdominal fat.

Dr. Cris Slentz, a senior researcher at Duke, explains the clinical implications of the study:

“The results of our investigation show that in sedentary overweight adults who continue to choose a sedentary lifestyle the detrimental effects are worse and more rapid than we previously thought. The data emphasizes the high cost of continued physical inactivity, the preventative abilities of modest amounts of exercise, and the substantial benefits to be gained by performing more exercise each week.”

Weighty Subject:

Surprising differences emerge when the study of visceral fat is extended to race, which is a key area of focus for researchers. Among the findings:

• A study undertaken by the State University of New York Health Science Center discovered an unusually high percentage of body fat in migrant Asian Indians. The report ends on this thought-provoking note: “Increased visceral fat in Asian Indians is associated with increased generalized obesity which is not apparent from their non-obese body mass index.”
• A comparison of visceral fat in African-American women and Caucasian women conducted by Louisiana State University confirmed what other studies before it had revealed—that African-American women have less visceral fat than their Caucasian counterparts.
• A joint research project involving Laval University in Quebec, and seven U.S.
universities concluded that Caucasians have greater visceral fat content than blacks.
• The International Journal of Obesity published a report indicating that Japanese men have larger areas of visceral fat than Caucasian men.
• The World Health Organization (WHO) projects that by 2025 half the world’s diabetics will be Asians.