It is well known that body composition is a major component of fitness and that excess body fat is not healthy. However, the distribution of body fat, e.g., where fat is located, is also an important health factor. Overall excess body fat can give someone a “pear” shape –where fat is deposited on the hips and buttocks, or an “apple” shape—where fat is deposited around the middle of the body. Research has shown that these two shapes have very different health implications.
Clinically known as central obesity, this location of excess fat has been associated with the incidence of a wide variety of cardiovascular and metabolic diseases, in particular, hypertension, dyslipidemia, insulin insensitivity and diabetes, as well as the presence of knee pain and osteoarthritis and asthma. Most recently, central adiposity hasalso been linked with Alzheimer’s disease.
A percent body fat measurement will not distinguish between the two body shapes. It is more useful to determine the waist-to-hip ratio (WHR) which takes a person’s body structure into account (see WHR measurement protocol below). According the World Health Organization, abdominal obesity is defined as a WHR above 0.90 for males and above 0.85 for females.
Other ways of determining abdominal obesity includes:
- Absolute waist circumference (>102 cm in men and >88 cm in women)
- Index of Central Obesity
- Sagittal Abdominal Diameter
It is important to note here that a differential diagnosis includes distinguishing central obesity from ascites and intestinal bloating, either of which could influence the WHR measurement.
There are two types of central abdominal fat, visceral and subcutaneous. Subcutaneous fat is located underneath the skin and can easily be measured in millimeters by skinfold calipers. A common
abdominal measurement is a vertical skinfold taken just to the right of the umbilicus. Visceral fat, also known as organ fat, is located inside the peritoneal cavity, packed in between internal organs
within the torso. A skinfold measurement on the abdomen of a person with a pot belly would not take the visceral fat into consideration. But visceral fat can be seen with powerful imaging techniques
such as magneticresonance imagining (MRI). It is this type of fat that makes the abdomen protrude excessively and is jokingly known as a beer gut or pot belly.
Of the two types of centrally located fat, it is believed that intra-abdominal fat conveys the bigger health risk. Research has shown that
- Surgical removal of visceral fat, but not subcutaneous fat, has been shown to extend the mean and maximum lifespan of rodents.
- Visceral fat, unlike subcutaneous fat, is implicated in many aging-associated diseases, for example, abdominal fat is a major source of increased inflammatory Interleukin associated with aging. as well as other inflammatory responses;
- Higher volumes of visceral fat, regardless of overall weight, has been associated with smaller brain volumes and increased risk of dementia
- There is a relationship between abdominal obesity and lung function.
Though there are medical treatments which have proven to be successful in reducing fat weight, a lifestyle change of increasing caloric expenditure through a permanent exercise routine and moderately reducing caloric intake is still necessary in order to maintain a target weight and percentage body mass when it is achieved. A combination of aerobic/cardio exercises and resistance training has been shown to be more effective than either mode alone. Your trainer should be able to prescribe an exercise program that will help you reach your weight goals.
WHR Measurement Protocol: Proper placement of a stretch-resistant measuring tape is important: for the hips, place the tape at the widest portion of the buttocks (usually at mid-point of buttocks from the side view), and for the waist, place the tape at the narrowest point (from the front view). If the waist is not apparent, place the tape at the midpoint between the bottom of the rib cage and the top of the iliac crest. For both measurements, the individual should be standing with feet close together, arms at the side, body weight evenly distributed, and wearing little clothing. The person should be relaxed, and the measurements should be taken at the end of a normal expiration, with tape measure placement parallel to the floor.