McDonald’s is selling black and white burgers in China.

In their ongoing efforts to get media attention, fast-food chains are turning from crazy concoctions - like bacon sundaes - to something a little more simplistic: different coloured foods.

Burger King will this week begin selling a new burger in Japan with a black bun. The Kuro burger (kuro means “black”) gets its colour from the bamboo charcoal mixed into its bun. Mmm… bamboo charcoal. It also features black ketchup, which is coloured by squid ink. Mmm… squid ink.

Burger King isn’t the first to try this. Earlier this month, McDonald’s rolled out a pair of burgers in China - one with a black bun, another with a white bun, with each being topped by sesame seeds of the opposite contrasting colour.

This is probably not something either company is likely to try in North America, where fast-food chains of all stripes are under considerable pressure to prove their products are natural. McDonald’s in particular has of late embarked on a PR campaign that seeks to remove the mystery from its food production process, while Taco Bell last year fought charges that its taco meat isn’t really meat.

As such, nothing says “unnatural” better than a coloured bun. There’s also the fact that humans are hard-wired to avoid foods of certain colours - especially black.