Fat – Facts & Fallacies
Fat. Everyone’s got it and everyone’s talking about it. It’s such a pervasive topic that everywhere we look, there is some media out there mentioning it. And most of the time, it’s often about how unhealthy it is. But is the case against fat so black and white? Or are we bombarded with only one side of a much larger and complex picture? This series of articles examine several notions about fat to see if we can’t answer these questions.
Fat Storage in Men & Women
Fat or adipose tissue is found in several places around the body. Generally, fat is stored under the skin and appears as visible fat. This type of fat is known as ‘subcutaneous fat’ and its storage around your body depends on your gender.
- Males generally store and carry fat in the chest, abdominal and butt areas giving rise to the image of the ‘apple’ shaped body.
- Females generally store and carry fat in the breasts, hips, waist and butt areas giving rise to the image of the ‘pear’ shaped body.
The other type of fat stored in the body is called ‘visceral fat’ and is the fat that accumulates around your organs, especially around the abdominal region. Several scientific journals have been able to show that visceral fat is the more dangerous of the two. Klein et al (2004)1 for example showed that reduction in subcutaneous body fat of between 28-44% in obese women through liposuction did nothing to improve upon insulin sensitivity, blood pressure, glucose and lipid levels.
Why Is Visceral Fat So Bad?
Fat around the organs is considered bad, however, the jury is still out on the exact reason why visceral fat is particularly harmful. Currently, there are three explanations as to why visceral fat is so dangerous:
- It disrupts hormones such as leptin and adiponectin which are responsible for feelings of fullness and appetite levels as well as affecting a cells ability to respond to insulin.
- Excess visceral fat results in increased cytokine production, which have been implicated to increase risks of cardiovascular disease.
- The location of visceral fat is close to the portal vein which connects to the liver, which can affect lipid production.
Subcutaneous vs Visceral Fat
It is important to note that compared to subcutaneous fat, visceral fat only makes up around 10% of total adipose tissue. Subcutaneous fat, although considered not as dangerous as visceral fat, is still a collection of fat tissue which can increase circulating levels of lipids. In addition, because subcutaneous fat is so extensive, excess accumulation can mean less exercise due to increases in weight, making exercise more difficult due to a heavier load and stress on the joints. On top of that, modern day aesthetics deem excess visible fat as less attractive.
Getting Rid of Visceral Fat
In terms of losing visceral fat, it seems that there is a dose-response relationship with exercise and visceral fat loss2. That is, the more exercise you do and the more intense the exercise is, there more visceral fat you stand to lose. In addition, it seems that strategies which promote moderate weight loss rather than large amounts of weight loss leads to greater visceral fat loss3. The same study also showed that one of the best strategies to lose visceral fat is to start a very low calorie diet. This led to excellent visceral fat reductions in the first 4 weeks with tapering of effects around the 3 month mark. It’s also interesting to know that testosterone can inhibit fat accumulation. Studies on older men have even shown that testosterone therapy can help decrease visceral fat levels4.
Subcutaneous & Visceral Fat - Summary
Below is a quick summary of all the points discussed so far and some extra bits:
- Visceral fat is extremely dangerous.
- Subcutaneous fat is considerably less dangerous
- Waist circumference is considered the best indicator of visceral fat and correlates well with development of chronic disease conditions.
- The waist measurement is when the tape measure goes around the belly button.
- Men should be under 94cm while women should be under 80cm.
- There are ethnic differences for these measurements – consult your GP for more information.
- Stress is a major modifiable factor controlling visceral fat accumulation
- Higher intensity and more frequent exercising results in larger reductions of visceral fat.
- A very low calorie diet is also quite effective.
- Both types of fat should be kept to a minimum however.
1 Klein S, Fontana L, Young VL, Coggan AR, Kilo C, Patterson BW, Mohammed BS. ‘Absence of an effect of liposuction on insulin action and risk factors for coronary heart disease.’ N Engl J Med. 2004 Jun 17;350(25):2549-57.
2 Ohkawara K, Tanaka S, Miyachi M, Ishikawa-Takata K, Tabata I. ‘A dose-response relation between aerobic exercise and visceral fat reduction: systematic review of clinical trials.’ Int J Obes (Lond). 2007 Dec;31(12):1786-97. Epub 2007 Jul 17.
3 Chaston TB, Dixon JB. ‘Factors associated with percent change in visceral versus subcutaneous abdominal fat during weight loss: findings from a systematic review.’ Int J Obes (Lond). 2008 Apr;32(4):619-28. Epub 2008 Jan 8.
4 Allan CA, Strauss BJ, Burger HG, Forbes EA, McLachlan RI. ‘Testosterone therapy prevents gain in visceral adipose tissue and loss of skeletal muscle in nonobese aging men.’ J Clin Endocrinol Metab. 2008 Jan;93(1):139-46. Epub 2007 Oct 16.