Just in time for bikini season, the syndicated “Rachael Ray Show” featured a new beauty machine with a girly-sounding name: the LiLa Strawberry Laser.  Advertised for quick slimming, the device involves low-level laser diode panels that are belted around a person’s waist for a series of 10-minute sessions.  “This thing right over here,” Ms. Ray said on a segment last month, pointing to a white console and treatment belt, “well, it claims that it can reduce your waistline by inches in just one 20-minute treatment.”  Ms. Ray introduced Candace, a young woman in a black sports bra and shorts, who was apparently unhappy with a slight convexity to her abdomen. Candace had just had her photo and measurements taken by Dr. David E. Halpern, a plastic surgeon from Tampa, Fla., who offers the device in his practice. Now he gave her the Strawberry treatment for 20 minutes.  “How many inches total has she lost?” Ms. Ray asked afterward.  “Eight inches off her circumference in the four areas measured,” Dr. Halpern reported — including, he added, about two inches off her lower abdomen. (He is a scientific adviser to LiLa Enterprise, a company in Suwanee, Ga., that distributes the device.)  On screen, a “before” profile photo of Candace with a slightly protruding abdomen appeared, next to a live video shot of her, taken from farther away, where she appeared more svelte. The audience clapped excitedly. “This is really remarkable,” Ms. Ray enthused.  Body-conscious consumers often jump on the latest technology that promises easy slimming, only to discard it for the next thinning gimmick. Inventions advertised as new technology to whittle waistlines have been around for decades. Vibrating belts were introduced in the 1920s, and massage rolling machines in the ’40s.  Today, the audience for superficial fat-zapping is largely composed of people hoping to transform themselves without the medical risks and recovery time entailed by invasive surgeries like tummy tucks and liposuction. The aesthetic medical industry has its own name for the category: “noninvasive body contouring.”  Devices in this category typically hit the skin with cold or thermal energy, in an effort to disrupt and diminish underlying fat cells. The machines can cost from $60,000 to about $110,000 — and that doesn’t include recurring use fees that some companies charge doctors for replacement treatment heads. Capital expenditures on the machines in the United States are expected to top $200 million by 2019, compared with around $73 million this year, according to projections from the Decision Resources Group, a health care analytics company. A session can cost consumers from $200 to several thousand dollars, depending on the type of device and the extent of the area to be treated.  “Physicians know there are patients who are willing to spend more money on noninvasive procedures than they would on an invasive procedure like liposuction,” April Lee, an aesthetics industry analyst at Decision Resources, told me. “As long as there is new technology, there will be people willing to try it.”  Oddly, the treatments aren’t aimed at the seriously overweight. Experts told me the ideal candidates are those who are already reasonably fit, exercise regularly, eat sensibly and just want to address an unwanted nubble here or there.  “If you are trying to lose 10 to 15 pounds, this is not for you,” says Dr. Mathew M. Avram, a dermatologist at Massachusetts General Hospital. “This is just sculpting areas to improve the appearance.”  The Food and Drug Administration vets the machines, but that doesn’t guarantee their effectiveness. For those manufacturers able to prove that their gizmos are comparable to devices that have already received federal clearance, the agency does not typically require rigorous, long-term scientific proof of benefit.  In fact, some methods for corroborating machines’ fat-busting claims in marketing — like before-and-after photos, or tape measures — can be quite unreliable. A person inhaling and sucking in her abdomen could have a waistline that is several inches smaller than when she is exhaling.  The F.D.A. has cleared the Strawberry Laser to reduce the waistline temporarily by hitting fat cells under the skin with low-level laser energy, causing cells to release their lipids. Consumers typically have eight sessions per treated region and are encouraged to exercise afterward to further the process.  Some medical experts are skeptical. Dr. Mark L. Jewell, a plastic surgeon in Eugene, Ore., who is a past president of the American Society for Aesthetic Plastic Surgery, contends that low-level laser devices are unlikely to result in significant changes since they emit about as much energy as a hand-held laser pointer.  “This defies reasonable thinking that in 20 minutes you could lose eight inches,” Dr. Jewell said of the “Rachael Ray” segment. (Dr. Jewell has conducted research for a different kind of device, Liposonix, which uses high-intensity focused ultrasound energy and for which more modest waistline-reduction claims are made.)  Mark Patterson, president of LiLa Enterprise, the distributor of the Strawberry Laser, said the results reported on “Rachael Ray” were typical of the device.  “We say ‘two inches or more in 20 minutes or less,’ ” he told me.  The leading procedure in the “noninvasive body contouring” category is called CoolSculpting. It is intended to freeze fat cells and prompt them to die off. Dermatologists at Mass General came up with the idea after pondering case reports of toddlers who developed divots in their cheeks after sucking on ice pops. (Dr. Avram is a scientific adviser to Zeltiq Aesthetics, the company behind the device.)  A CoolSculpting treatment involves clamping and cooling a section of fat about the size of a stick of butter for one to three hours. After 12 weeks, the fat layer of each treated area has typically diminished by about 20 percent or more, according to company-financed studies on pigs and humans. In very rare cases, people have developed lumps of fat after the procedure. For the moment, at least, consumers seem convinced. Zeltiq reported net revenue of $111.6 million last year, compared with $76.2 million the year before.  Of course, the next ostensible fat buster is already on the horizon. A drug company in California is developing a fat-melting injection to be aimed, at least initially, at people seeking to downsize a double chin.  A version of this article appears in print on June 1, 2014, on page BU3 of the New York edition with the headline: The Enduring Promise of a Thinner You. Order Reprints|Today's Paper|Subscribe
New fat-zappers are the latest in a long line of products advertised as offering quick slimming without surgery.