The Skinny on Body Fat: A HealthCentral Explainer

SSuchy Editor
  • Two types of fat

     

    The human body has two different types of fat tissue, brown fat and white fat.  Both types serve a distinctive function for the body.

     

    White fat is what’s visible on your body when you put on extra pounds. A person needs to consume calories each day to provide his or her body with fuel to carry out all of the functions necessary for survival.  The body burns calories through physical activity, of course, but it also needs calories to carry out processes as seemingly sedentary as digestion, breathing and even thinking.

     

    So, when the body ingests calories, it will either use the calories right away or store them for later use. White fat is how those excess calories are stored.  The more extra calories the body consumes that are not used, the more white fat will accumulate.

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    In a healthy person who is not overweight, white fat accounts for 20 percent of body weight in men and 25 percent in women. 

     

    So what’s brown fat?

     

    Brown fat’s primary function is to generate body heat by burning calories and is present in all mammals to different degrees.  It is especially abundant in hibernating animals who are not physically active and in human infants who are not yet able to shiver to keep warm. 

     

    Humans and other mammals with high levels of brown fat take longer to start shivering from the cold than those with low levels.  People with high brown fat levels also, according to some studies, burn calories at a faster rate and tend to be thinner.  For this reason, a lot of research has been dedicated to the possible weight-loss benefits of brown fat, but no definitive conclusions have been drawn.

     

    Location, Location, Location

     

    White fat is more abundant on the human body and does not have the calorie-burning effects of brown fat.  Also,  where white fat is located on the body does make a difference in its impact on our health, especially if it’s stored around the midsection of the body.

     

    There are two types of white fat stored in the midsection (abdomen, hips, thighs): visceral fat and subcutaneous fat. 

    Subcutaneous fat is the fat that accumulates near the surface of the skin around the stomach, hips and thighs and contributes to a ‘pear-shaped’ silhouette.  You can often see and grasp at subcutaneous fat.

     

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    Visceral fat, on the other hand, accumulates behind the abdominal cavity near the internal organs.  You can’t grasp it, but it contributes to an ‘apple-shaped’ physique or ‘beer belly’. 

     

    The bad role of fat

     

    Scientists used to think of body fat, especially visceral white fat, as simply a storage depot for calories waiting to be used.  Too much body fat was unsightly, but was not believed to cause health problems.  Research now suggests that these white adipose tissue deposits, especially around the abdomen, are biologically active and their presence and activity can have a substantial effect on your health. 

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    Too much of either type of fat on the body is not ideal, but studies have found that visceral fat is a much greater threat to general health than subcutaneous fat.  Specifically, excess visceral fat contributes to problems such as Type 2 diabetes and heart disease. 

     

    For example, some studies have shown that visceral fat pumps out immune system chemicals called cytokines.  These chemicals can increase the risk of cardiovascular diseases and cause insulin resistance, a hallmark of Type 2 diabetes.

     

    Fortunately, visceral white fat can be burned off with proper nutrition and exercise.  Subcutaneous fat can be harder to shed, but in people with normal weight, it’s not as big of a health risk as visceral fat.

     

     

    Bibliography:

     

    Abdominal fat and what to do about it (December 2006). Harvard Health Publications. Retrieved from: http://www.health.harvard.edu/newsweek/Abdominal-fat-and-what-to-do-about-it.htm

     

    Nordqvist, Christina. What is Brown Fat? What is Brown Adipose Tissue? (January, 2012). Medical News Today. Retrieved from: http://www.medicalnewstoday.com/articles/240989.php

     

    Columbia University Medical Center (2012, August 2). Turning white fat into energy-burning brown fat: Hope for new obesity and diabetes treatments.  ScienceDaily. Retrieved from: http://www.sciencedaily.com/releases/2012/08/120802122305.htm

Published On: September 17, 2012