Liposuction and Fat Regain

If body fat really is actively regulated by the body, rather than just being a passive result of voluntary food intake and exercise behaviors, then liposuction shouldn't be very effective at reducing total fat mass in the long run.  People should return to their body fat "setpoint" rather than remaining at a lower fat mass. 

Teri L. Hernandez and colleagues recently performed the first ever randomized liposuction study to answer this question (1).  Participants were randomly selected to either receive liposuction, or not.  They were all instructed not to make any lifestyle changes for the duration of the study, and body fatness was measured at 6 weeks, 6 months and one year by DXA. 

At 6 weeks, the liposuction group was significantly leaner than the control group.  At 6 months, the difference between the two groups had decreased.  At one year, it had decreased further and the difference between the groups was no longer statistically significant.  Furthermore, the liposuction group regained fat disproportionately in the abdominal area (belly), which is more dangerous than where it was before. The investigators stated:

We conclude that [body fat] is not only restored to baseline levels in nonobese women after small-volume liposuction, but is redistributed abdominally.

This is consistent with animal studies showing that when you surgically remove fat, total fat mass "catches up" to animals that had no fat removed (2).  Fat mass is too important to be left up to chance.  That's why the body regulates it, and that's why any satisfying resolution of obesity must address that regulatory mechanism.