The Advertising Standards Authority (ASA) said the burger giant’s claim that the burger is “100% Whopper, no beef” could be understood to mean it did not contain animal products.
Burger King said that it had been “clear and transparent” in its marketing and that it had communicated from the outset that the Rebel Whopper is aimed at a flexitarian audience.
Small print at the bottom of some of the adverts stated that the Rebel Whopper may not be suitable for vegans or vegetarians as it was cooked alongside other meat products and that the mayonnaise contained egg.
The fast food chain also said that a customers could order the burger without mayonnaise.
Supplied by Unilever under its Vegetarian Butcher brand, the patties are 100% plant-based.
But the ASA upheld the complaint, saying that the green colour palette and the timing of the ad and product release to coincide with Veganuary gave the impression that the product was suitable for vegans and vegetarians.
Burger King has already come under fire online over the Rebel Whopper not being suitable for vegans.
Last year, the company launched a meat-free halloumi burger that was unsuitable for vegetarians as it was cooked in the same oil as chicken and fish.