When I tell people how I make much of my living—as a psychotherapist hypnotizing people slim—they inevitably ask: Does it work? My answer usually brightens their eyes with something between excitement and incredulity. 

Most people, including my colleagues at Harvard Medical School, where I teach hypnosis, don't realize that adding trance to your weight loss efforts can help you lose more weight and keep it off longer. 

Hypnosis predates carb and calorie counting by a few centuries, but this age-old attention-focusing technique has yet to be embraced wholeheartedly as an effective weight loss strategy. 

Until recently, there has been scant scientific evidence to support the legitimate claims of respected hypnotherapists, and a glut of pie-in-the-sky promises from their problem cousins, stage hypnotists, hasn't helped.

Even after a persuasive mid-nineties reanalysis of 18 hypnotic studies showed that psychotherapy clients who learned self-hypnosis lost twice as much weight as those who didn't (and, in one study, kept it off two years after treatment ended), hypnotherapy has remained a well-kept weight loss secret.

Unless hypnosis has happily compelled you or someone you know to buy a new, smaller wardrobe, it may be hard to believe that this mind-over-body approach could help you get a handle on eating.