Hip fat is 'good', but pot belly 'bad'

Not all body flab is harmful - hip fat is good but pot bellies are bad, claims a new study.

Previous studies have revealed that subcutaneous fat is merely the lesser of the two evils. Now, researchers in the United States have concluded that it could actually be positively beneficial.

A team at the Joslin Diabetes Centre in Boston has found that the worst kind is actually the excess fat on the internal organs, which causes a pot belly and is known as visceral fat.

According to them, people with visceral fat are more likely to suffer from heart disease and insulin resistance, which leads to type II diabetes, than those who put on fat under their skin on their hips and thighs.

In their study, the researchers, led by C Ronald Kahn, transplanted subcutaneous fat into the bodies of some mice and visceral fat into others.

They found the laboratory mice that had received subcutaneous fat ended up with lighter, leaner bodies and less insulin resistance than the animals that got visceral fat and, crucially, those that received no fat transplant at all.

''That increased body fat has a favourable effect is something I buy into,'' the New Scientist quoted John Miles of the Mayo Clinic in Rochester as saying.

If subcutaneous fat also has benefits in humans, the results could explain why liposuction, which removes this fat, does not reduce diabetes or other side effects of obesity, according to the researchers.

How subcutaneous fat exerts its positive influence remains a mystery, but Kahn suspects it secretes hormones that speed up metabolism.