Lots of pills and gadgets promise to help you "burn" fat. And they almost always disappoint. Maybe it's all a matter of degrees. Instead of burning fat, should you be trying to freeze it instead?  Check out the latest....

Two new products take a cold approach to fat loss. In September, the Food and Drug Administration approved Zeltiq's CoolSculpting system for fat removal. Offered at doctors' offices across the country — including almost 30 in California, according to the company's website — the procedure supposedly kills fat cells through extreme cold.

The doctor applies a cup-shaped applicator to a problem spot such as a "love handle" or a paunchy belly. The area is then gently sucked up into the applicator and dramatically cooled for up to one hour. (The temperature that's reached is a company secret.) Patients are told to start looking for results about three weeks after the treatment but that they may have to wait a couple of months for the complete effects to kick in. You can expect to pay $700 or more for each individual treatment, which means tackling a set of love handles would cost about $1,400. Add the belly and you're up to about $2,100. The website says that some spots may need more than one treatment.

CoolSculpting Claims

The CoolSculpting website says the procedure can "target, cool, and eliminate fat cells without damage to other tissue" and can "reduce the fat layer by 20 to 40%."

"This is not a weight-loss device," says Dr. Mathew Avram, director of the Dermatology Laser and Cosmetic Center at Massachusetts General Hospital at Boston. Avram has performed more than 50 of these procedures in his clinic. He's also a stockholder in Zeltiq. In his opinion, CoolSculpting works best for people who want to trim down isolated bulges.

The website for the Cool Shapes shorts says that "scientists around the world have discovered that fat cells are highly sensitive to cold." Specifically, cold is said to kill white fat while energizing brown fat, the desirable type of fat that helps burn calories.

Jamie Burke, who founded the company along with her sister Lark MacPhail, says that customers can "start to notice a difference in firmness and volume" within five weeks. "The fat cells are flushed out gradually and slowly," she says.

The Bottom Line

Freezing away fat may seem like an odd concept, but carefully applied cold really can trim a waistline, says Dr. Jeffrey Kenkel, professor of plastic surgery at the University of Texas Southwestern Medical Center at Dallas. Though he doubts that Cool Shapes shorts could get cold enough to make a difference, he sees real potential for the CoolSculpting system. "This is good news for patients," says Kenkel, who is also president-elect of the American Society for Aesthetic Plastic Surgery. "It's not a replacement for liposuction, but it does provide another option."

Still, Kenkel adds that the results of CoolSculpting will be modest at best. "Patients might notice a difference in the way their clothes fit," he says. "They aren't going to be looking in the mirror and saying, 'Wow!'"

In 2009, Avram and colleagues published an article in Seminars in Cutaneous Medicine and Surgery describing results of the CoolSculpting system. Using before-and-after ultrasound imaging of 10 patients, the researchers found that the treatment reduced the thickness of fat in the "love handles" by more than 20% after four months. Mild side effects, including bruising and numbness, generally went away after about a week.

He adds that interest in cold therapy for fat removal got its start in the early 1970s when doctors noticed that children who spent a lot of time sucking on popsicles tended to have unusually hollow cheeks.

Dr. David Edelson, a weight-loss specialist and assistant clinical professor of medicine at Albert Einstein College of Medicine in New York City, says that he applauds the makers of Cool Shorts for "thinking outside of the box" and coming up with a product based on real science.

He's not convinced that the shorts would work, though — not until he sees some actual data. "I would encourage them to do some clinical studies," he says. One potential problem, he says, is that people tend to carry brown fat on their necks and upper back, so the gel packs on the hips or belly definitely miss many of the cells they're supposedly stimulating.

"There are worse ways to spend your money," he adds. "There's very little risk, except you might get a little chilly."