There appear to be no shortcuts in life. A new study finds that very obese people who reduce their weight by undergoing liposuction, instead of cutting back on calories, fail to improve their long-term health prospects.
As a public health problem, obesity is a well-known risk factor for diabetes and heart disease. At the microscopic level, fat cells have been implicated in the production of inflammatory proteins (SN: 2/28/04, p. 139: Available to subscribers at Inflammatory Fat); the chronic inflammation they induce may explain much of the heightened disease risk.
To ascertain whether liposuction might lessen this risk, gastroenterologist Samuel Klein of Washington University in St. Louis and his colleagues designed a study in which surgeons removed roughly 10 kilograms of fatty tissue from each of 15 very obese women. Seven of the women had type 2 diabetes, the kind that usually hits in middle age or later.
On average, four times as much fat was removed in the study’s liposuction procedures than during a typical liposuction surgery. The researchers chose that protocol to accentuate any biological changes resulting from the surgery. Also, doctors instructed the women to adhere to their usual eating and exercise habits after surgery so that any physiological effects of liposuction wouldn’t be confounded by a new diet or an exercise spree.
Ten to 12 weeks after surgery, the researchers took blood samples from each volunteer and measured each woman’s sugar metabolism. Compared to the results of similar tests done before surgery, the scores showed no change in sugar breakdown or blood concentrations of tumor necrosis factor (TNF)-alpha. This inflammatory compound has been linked to insulin resistance—a precursor condition to diabetes.
Next, the researchers considered two other inflammatory compounds, called C-reactive protein (CRP) and interleukin-6, and triglycerides. Blood concentrations of these compounds, which all appear to contribute to heart disease risk, didn’t drop after liposuction.
The surgery also had no effect on the women’s blood pressure readings, the team reports in the June 17 New England Journal of Medicine. The findings were the same whether or not the participants had diabetes.
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Had these women lost this much weight by dieting or increased exercise, Klein says, their sugar metabolism would have improved and they would have seen lower scores for TNF-alpha, CRP, interleukin-6, triglycerides, and blood pressure.
Klein notes that dieting and liposuction induce fat loss in the abdomen but only dieting reduces fat in visceral organs and muscle. Indeed, earlier studies of animals show that surgical removal of visceral fat eases insulin resistance, whereas removing abdominal fat doesn’t.
The new study is well done “and really surprising,” says plastic surgeon Sharon Y. Giese of the New York (N.Y.) Eye and Ear Infirmary. Its results run counter to effects she has seen in her practice and research. In a study reported in 2001, Giese found that people without diabetes who were moderately overweight—carrying an extra 5 to 50 pounds—show significantly improved sugar metabolism after liposuction.
It could be that extremely obese people are “so far along into the [diabetes] disease process” that liposuction doesn’t help them, she says. Meanwhile, Giese plans to analyze blood samples from the people she analyzed previously to see if their inflammatory markers changed after surgery.