Subcutaneous vs. visceral fat: Which matters most when battling the bulge?

There are an estimated 97 million adults in the US that are overweight or obese (NHLBI). The battle of the bulge is a unique challenge for both sexes looking to achieve weight management goals.

Perhaps, an increased understanding of the etiology of the different sources of fat may help guide the dieter to achieving a successful end result.

According to the National Heart Lung Blood Institute’s Obesity Education Initiative, body mass index (BMI) is a measure of body fat on height and weight in both adult men and women (NHLBI). It is important to note that these measures are suited for adults only and not applicable to children. The aim of BMI has always been to assess weight against respective height standards established by the Department of Health and Human Services (DHHS). Furthermore, clinical evidence suggests that a weight loss of 5-10% of initial weight will lower the risk of disease (DHHS). As a result, physicians and other health care providers utilize the results of this tool as a baseline to guide effective weight management. In addition, clinical guidelines also assess relative risk and weight circumference. Understanding these outputs, allows the health care provider to suggest a treatment plan to the dieter.

What is interesting about the process of weight management; there appears to be a scarcity of information on the differences between subcutaneous fat and visceral fat-and the tenuous relationship with the dieter’s goals. The aim of the article is to shed more light on both types of fat and perhaps, justify why it is important for the dieter to have a basic understanding of these two types of fat, as the dieter progresses on the path to weight loss.

Subcutaneous fat is found beneath the epidermis (outermost layer of skin) and is the protective wrap over the body’s surface. The body surface is made up of stratified squamous epithelium with an underlying basal lamina. Subcutaneous fat can be measured using body fat calipers, which provide a rough estimate of total body adiposity. There is much discussion on the effectiveness of body fat calipers. The tool is considered to be the most popular tool to assess body fat.

Adipose tissue is loose connective tissue. In humans, obesity does not depend on t body weight, but the amount of body fat-specifically adipose tissue (Kershaw, 2004). In this light, where is adipose tissue distributed the most? Are there distinctions between men and women and adipose accumulation? There are gender differences in adipose or fat distribution. The pear scenario in women is often contributed to adipose accumulation in women’s thighs and buttocks compared to men-where fat accumulation is prevalent in mid-section and chest. Interestingly enough, the lipoprotein lipase, is correlated with more women compared to men. This is primarily due an enzyme that is necessary for fat storage in women. Lipase does have a secondary role in men, but due to lack of enzyme that evades most men, the observation appears to more prevalent in women.

Consequently, there has been considerable debate over the role that subcutaneous fat plays in loosing weight and an individual’s overall appearance. Based on (Abe, T., Sugita, M & Fukunaga T, 1997; Hickey et al, 1997) a study examined the role of exercise (anaerobic and aerobic) in women: Study results revealed that the cohort that exercised 3-4 days a week compared with those who exercised just 1-2 days lost more subcutaneous fat in a 13 week exercise and diet regimen.

Visceral fat also known as organ fat is located inside the peritoneal cavity. Peritoneal cavity is the serous membrane that invests viscera. It is comprised of parietal and visceral peritoneum. In other words, visceral fat is located between the organs and contributes to belly fat. Compared with subcutaneous fat which is found beneath the epidermis. Visceral fat is composed of several adipose depots which may contribute insulin resistance, glucose intolerance, dyslipidemia, hypertension and coronary artery disease (NIH). Several studies have linked visceral fat to elevated triglycerides levels (Wirth et al, 1996). New methods are under review to appropriately measure visceral fat. One method that has gained traction is bioelectricity impedance method (Onda, T, 2006). Researchers in Japan believe that voltage which generated at the lateroabdominal area of the waste, will calculate visceral fat area more effectively. Clinical trials are still in progress, but researchers also hope that the device will address metabolic syndrome.

Considering that coronary artery disease is a condition that in which plaque builds up inside the coronary arteries and the plaque comprises fat, cholesterol and calcium that may lead atherosclerosis; visceral fat should get more attention. Furthermore, heart disease is the leading cause death in women 47.1% and 53% in men respectively (MMWR, 2008) with a cumulative cost at $500 billion (CDC) in 2005. These costs include health care expenditures, lost productivity, hospitalization costs for Medicare beneficiaries and health care spending attributed to high blood pressure. As a result, mortality and financial trends associated with heart disease seem to suggest that future efforts in conjunction with Healthy People 2010 and it leading health indicators; should increase r social marketing awareness of visceral fat and the associated effects in men and women. Which matters the most in the battle of the bulge? In my opinion, based on current health trends and leading health indicators in Healthy People 2010; the dieter’s arsenal should include a detailed action plan to address visceral fat.

References
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National Heart Lung and Blood Institute. [Online]. Obesity Education Initiative: Calculate Your Body Mass Index. Retrieved from http://www.nhlbisupport.com/bmi/ on March 31, 2008.

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Abe, T., Kawakami, Y., Sugita, M., & Fukunaga, T. (1997). Relationship between training frequency and subcutaneous and visceral fat in women. Medicine and Science in Sports and Exercise, 29, 1549-1553

Hickey MS, Houmard JA, Considine RV, et al. Gender-dependent effects of exercise training on serum leptin levels in humans. Am J Physiol. 1997;272(4 Pt 1):E562-566.

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MMWR. (2008). American Heart Month—February 2008. Retrieved from http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5704a1.htm on March 31, 2008.

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Healthy People 2010. [Online]. Retrieved from http://www.healthypeople.gov/LHI/lhiwhat.htm on March 31, 2008.