Burger King was recently hit with a lawsuit by a customer who asserts that the chain is misleading people about its plant-based Impossible Whoppers. The faux-meat burgers, the suit says, are advertised as a meat-free option, but are actually contaminated with beef byproducts because they are cooked on the same grills as its regular burgers.

Because the Restaurant Brands International (NYSE:QSR) burger chain marketed the sandwich as "100% Whopper, 0% beef," but cooked those plant-based burgers in the juices of beef patties, Burger King engaged in "deceptive representations," the suit claims. The plaintiff is a vegan, and his suit seeking class action status seeks damages and a ruling requiring Burger King to disclose that the Impossible burgers are cooked on the same grill as other meats.

The restaurant does already tell people they can request the burgers be cooked off the grill, in a microwave.

A man taking a big bite of a burger

Image source: Getty Images.

A burger for everyone

While vegans and vegetarians are an obvious target market for burgers like the Impossible Whopper -- which is made with patties from Impossible Foods -- or Beyond Meat's own plant-based alternative -- the Beyond Burger -- they are not marketed by the companies as vegan or vegetarian. The companies are aiming at a larger audience the includes people who want to eat less meat.

Moreover, the Impossible Whopper comes standard with regular mayonnaise, which, being egg-based, is not vegan. And while Burger King has long been the home of "have it your way," meaning a customer can always request their burger without mayo, the standard ordering option would not be appropriate for vegans.

Burger King's website also advises that for "guests looking for a meat-free option, a non-broiler method of preparation is available upon request," implicitly acknowledging that the plant-based patties are normally cooked on the same grills as beef burgers.

The makers of meat alternative products even chafe when their products are placed in the vegan or specialty foods sections of grocery stores; it's their view that they should be displayed right alongside beef. Beyond Meat tells consumers looking for its patties and ground beef alternatives: "Find it in the meat aisle."

Only about 3% of the population, at most, considers itself vegan, so manufacturers don't want to be boxed in to marketing to such a tiny niche. As Impossible Foods tells restaurants, meat-eaters don't want to eat so-called vegan food or faux meat. "Yes, Impossible meat is plant-based," its website says, "but it wasn't made for vegans. It's actually made for people who love meat."

A potentially expensive remedy

While some restaurant chains such as White Castle do cook their faux meat patties on separate grills, and others try as best as they can to accommodate their vegan customers by keeping them separate, but, as a Carl's Jr. executive told Forbes, "we do handle animal protein back of house so we cannot claim fully that it's prepared in any form or fashion."

If this lawsuit leads to a ruling that forces Burger King to have separate, meat-free grills to cook plant-based burgers, that could be a problem. Adding the grills would be an expensive fix and Burger King would likely find it easier and cheaper to drop the Impossible Whopper from the menu.

One of the big reasons McDonald's took so long to implement all-day breakfast at its restaurants was because the move required franchisees to buy new, bigger ovens, and to have kitchens set up to cook both breakfast and dinner orders at the same time. Franchisees balked at having to lay out the money for those operational upgrades.

Even today, after several years of the program running -- and proving extremely popular with customers -- it's still a sore point for franchisees. It's for that reason that McDonald's has begun allowing franchisees some latitude to limit which breakfast items to offer on the all-day menu.

The law of unintended consequences

The food service and restaurant segment is the fastest-growing portion of Beyond Meat's business, with sales growing nearly 400% to $95.3 million during the first nine months of the year, compared to a 180% increase in retail sales, which hit $104.2 million. At this rate, restaurants will become the bigger portion of Beyond Meat's business very soon.

Because the lawsuit is only asking Burger King for clearer advertising (and for damages), the restaurant might decide it doesn't mind potentially alienating the small portion of its customer base that are vegans and will simply state the situation more clearly, rather than install separate grills.

After all, Burger King said 90% of the people who tried the Impossible Whopper when it tested the burger were meat-eaters, so they likely didn't care if those burgers were cooked on the same grills as traditional patties. But if other chains view carrying plant-based burgers as a hassle that opens them up to potential lawsuits, they may opt against putting the burgers on their menus altogether.

A ruling against Burger King could have faux-meat makers finding their expansion opportunities are more limited. And vegans could have fewer restaurant options available to them.