Weight reductionLiposuctioning your waistline can make you look fabulous, but it won't necessarily make you healthier.
In a study, obese women who dropped up to 23lb of belly fat by way of liposuction did not appear to lower their risk of diabetes or heart disease, both of which are fat-related.
It is a frustrating and surprising finding to researchers who believed that surgically removing fat would help restore a healthier body chemistry.
"It's not how much fat you remove, but how you remove the fat that is really what is more important," said lead study author Dr Samuel Klein of Washington University in St Louis.
"We have to go back to the same old traditional recommendation of lose weight and be more physically active."
Liposuction is the United States's most popular form of cosmetic surgery. About 400,000 "fat-sucking" liposuction procedures are done every year.
The study, published in the latest issue of the New England Journal of Medicine, involved 15 obese women who underwent cosmetic liposuction.
The women's blood chemistry and pressure - which reflect the risk of diabetes and heart disease - were checked before surgery and about three months after.While the women were slimmer afterwards, their medical profiles were almost identical.
Body fat has been tied to diabetes, heart disease, cancer and other diseases in recent years. Results show that fat doesn't just make the heart pump harder, fat cells churn out a brew of harmful metabolic products.
The notion that surgically removing fat should help restore a healthier chemistry to the body cannot be completely discarded, however. For one thing, this study involved a small number of people - all of them women.
Also, Barbara Corkey, a Boston Medical Centre biochemist who is president of the North American Association for the Study of Obesity, said the liposuction may have left too much body fat behind or siphoned away the wrong kind of fat.
The surgery removed only belly fat, leaving untouched a deeper layer of what is known as visceral fat. The deeper fat may prove to be more dangerous. It feeds metabolic products more directly into the pancreas, which manufactures the hormone insulin. It is insulin production or metabolism that goes haywire in diabetics. Visceral fat is harder, but not impossible, to trim by surgery.
Ultimately, doctors may find that fat cells need to shrink in size, and not just number, to restore a healthier chemical balance. Dieting makes fat cells smaller.
The liposuction research suggests that "even if one could suddenly remove the fat tissue per se, you really haven't changed the underlying process," said Dr David Kelley, who runs the Obesity and Nutrition Research Centre at the University of Pittsburgh Medical Centre.