Body fat distribution and the health risks of obesity.

Excess body fat is stored at multiple sites in the human body. Most of it is stored under the skin in the form of subcutaneous fat. A small quantity is located in the abdominal cavity connected to pancreas, intestine and other organs. This is called visceral or intra-abdominal fat, and it is adding more risks to the health than the subcutaneous fat. People with high amount of visceral fat have a large waist (central or abdominal obesity) and and apple shaped body. People with high subcutaneous fat on the buttocks or legs have a pear shaped body. Waist fat pinched during measurements is subcutaneous fat. A proper estimation of visceral and subcutaneous fat is done via MRI (magnetic resonance imaging). A cross sectional image made at the abdominal level will make possible to visualize the different fat depots and calculate visceral/subcutaneous fat surface area. But for the ones without the technical availability of MRI, the amount of visceral fat is relatively well correlated with the waist circumference and/or waist to hip ratio. Obesity rates are different between countries (geographic areas). The highest obesity rates are recorded in the Pacific Islands area, due to an energy rich diet and genetic predisposition towards obesity (US and Australia included). Lower obesity rates are recorder in most European, African and Asian countries, with Ethiopia and Eritrea being the lowest.

When BMI is higher than 30, which translate by being obese, the mortality risk increase, with problems such as cardio-vascular diseases, stroke, sleep apnoea, diabetes, lung disease, liver and pancreas problems and even cancer risk also increasing. The metabolic syndrome is characterized by abdominal obesity, hypertension, elevated blood cholesterol and triglycerides increased, insulin resistance (pre-condition of type 2 diabetes) and a higher chance of heightened inflammatory state and blood clotting. Type 2 diabetes is often associated with obesity, but the loss of body fat cause immediate improvement of this condition. Increases in fat mass causes the fat tissue to become inflamed (state of chronic low grade inflammation). Obesity increase the tendency of the blood to clot, which is another important risk.

Next post: causes of obesity.

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G.