Women who have fat removed from their hips by liposuction are likely to see it come back again within 12 months, only this time to the belly, according to new research from the US that was published online in the journal Obesity this week.

Drs Teri L. Hernandez and Robert H. Eckel of the University of Colorado, Denver, and colleagues, wrote in their background information that there were no published reports of randomized studies on humans that examined whether fat came back after it was removed, and if it did, was it to the same place or elsewhere in the body.

So they carried out a randomized controlled trial of liposuction in 32 non-obese healthy female volunteers with disproportionate body fat distribution, that is mostly in the lower abdomen, hips or thighs.

At the start of the study, they measured the women’s body composition in various ways. The primary measure was DXA (dual-energy X-ray absorptiometry), with additional measures including abdominal, leg and arm circumferences, thickness of subcutaneous skinfold, and MRI scans of torso and thighs.

Then the women were randomly assigned to one of two groups: 14 who underwent small-volume liposuction within 2 to 4 weeks (their average BMI was 24 kg/m2), and 18 to a control group (average BMI was 25 kg/m2) that was offered liposuction after the study completed.

All the measurements were taken again at 6 weeks, 6 months and 12 months afterwards. The women agreed not to make any lifestyle changes, such as change their eating or exercise habits, while they were enrolled on the study.

The researchers compared the measurements taken over the 12 months and found:

  • After 6 weeks, the percentage body fat (measured by DXA) went down by 2.1% in the liposuction group and 0.28% in the control group: a statistically significant difference of 1.82% between the two groups (after adjusting for between group differences in this measure at baseline).
  • This difference was smaller at 6 months, and by the 12 month mark it was no longer statistically significant.
  • The fat reaccumulated differently at various parts of the body.
  • After 1 year the thigh region of the liposuction participants remained reduced, but fat accumulated in their abdominal region, compared to controls.

The researchers concluded that after liposuction, body fat “was restored and redistributed from the thigh to the abdomen”.

Eckel told the press that the fat was “redistributed upstairs”, mostly in the upper abdomen, but also in the shoulders and upper arms, according to a report in the New York Times.

Obesity experts suggest that the human body “defends” its fat, and if you try to lose it, it will find a way to bring it back. And the explanation for why the fat does not return to the thighs is that the liposuction destroys the “scaffolding” infrastructure that holds fat in place, so it finds somewhere else to settle.

Eckel also said the women in the liposuction group were nonetheless delighted with their results, they didn’t like having the fat around their hips and thighs and just wanted it gone.

And more than half the women in the control group chose to have the liposuction after the study completed, despite knowing the results.

“Fat Redistribution Following Suction Lipectomy: Defense of Body Fat and Patterns of Restoration.”
Teri L. Hernandez, John M. Kittelson, Christopher K. Law, Lawrence L. Ketch, Nicole R. Stob, Rachel C. Lindstrom, Ann Scherzinger, Elizabeth R. Stamm and Robert H. Eckel.
Obesity published online 7 April 2011.
DOI:10.1038/oby.2011.64

Additional source: New York Times.

Written by: Catharine Paddock, PhD