A third class action lawsuit has been filed in California federal court against shoemaker Skechers, alleging that the company deceived consumers about the health benefits of its “Shape-up” line of shoes.

Print, television, and Internet ads, according to the complaint, tout the “noticeable physiological benefits to consumers” of the shoes, including weight loss, firmer muscles, reduced cellulite, improved circulation, and improved posture. Plaintiff Venus Morga claims that she paid a premium for the shoes and did not experience any of the benefits described by Skechers in its advertising.

The Shape-ups contain what Skechers describes as a “unique kinetic wedge,” or a piece of foam, that is, thicker at the heel and progressively thinner towards the toes, which alters the way the wearer stands and walks. Relying on clinical studies, Sketchers maintains that the altered posture results in health benefits that allow wearers to “[g]et in shape without setting foot in a gym.” But the suit claims that the studies are bogus“marketing tools and that the shoes can actually harm wearers who have flat feet or preexisting difficulties with balance.

Morga is the third plaintiff in as many months to file suit over the shoes. Two other plaintiffs made similar claims in suits filed in June and July in California federal courts. All three suits argue that Skechers violated California’s unfair business practices law by engaging in deceptive advertising.

To read the complaint in Morga v. Skechers, click here.

Why it matters: Advertisers should be careful to use claims that are substantiated, and that studies used in support produce accurate, verifiable results.