Eight surgical centers in California and marketing firm 1-800-GET-THIN LLC were issued warning letters from the U.S. Food and Drug Administration (FDA) today regarding ‘misleading advertising’ of an FDA-approved weight loss device.

The FDA raised concerns that advertisements for the device, branded as the Lap-Band, lack information on the risks of a procedure known as gastric banding.

Gastric banding is the implantation of a device around the stomach for weight loss in adults considered obese, based on body mass index and obesity-related medical conditions.

In addition to what the FDA is calling “misbranding,” the administration also noted that the font size of information printed on these advertisements related to such risks “is too small to be read by consumers.”

The warning letters were issued to the following surgical centers: Bakersfield Surgery Institute Inc.; Beverly Hills Surgery Center; Palmdale Ambulatory Center; Valley Surgical Center; Top Surgeons LLC; Valencia Ambulatory Center LLC; Cosmopolitan Plastic & Reconstructive Surgery; and San Diego Ambulatory Center LLC.

“The FDA takes seriously its responsibility to protect consumers from products promoted without adequate warnings,” Steve Silverman, director of the Office of Compliance in the FDA’s Center for Devices and Radiological Health, said in a statement. “It’s particularly troublesome when advertisements don’t communicate the serious risks associated with medical devices.”

If the warned surgical centers and marketing firm do not make recommended adjustments to existing advertising campaigns, the FDA may seek further action such as “product seizure or civil money penalties.”