Burger King's Halloween Burger Dyes Your Poo Green, and We Think We Know Why

By Gizmodo on at

Burger King’s Halloween Burger turns poo the kind of comically bright green that would humiliate most goths. The question on everybody’s lips, and other less-mentionable parts, is why?

It’s been well-established that consuming this burger will likely leave you with lingering effects the next time you go to the toilet. What goes in black will come out green. Not grass-green, but cartoon leprechaun-green. (Be Warned: There is an actual picture in the link.)

People have speculated as to why ever since. A few people think it’s the A-1 steak sauce. Medical Daily notes that green dye is often used to make black food colouring. Burger King has put out a list of components in the food, in which they state that all ingredients in the burger are common in the food industry and are within the Acceptable Daily Intake put out by the US FDA. (They also insist on calling the burger the HA. 1. LOWEEN WHOPPER.)

But while the poo is indisputably green, the dye causing it might not be. The dyes that make the bun black are a combination of Yellow #6, Red #40, Caramel Colour, and Blue #1. Blue #1 is also known as Brilliant Blue FCF. Brilliant Blue doesn’t absorb well in the intestines, so it often comes out in the poo—it just doesn’t come out blue. The internet is full of concerned parents talking about giving their kids a purple drink or smoothie (made with red and blue food colouring) only to change green nappies or find green stains on underwear. Brilliant blue is often combined with tartrazine, a yellow food dye, to make green dye. A site called The Poop Report claims that blue food dye (Blue #5 this time) combines with bile to make poo green, although bile by itself can turn poo green.

In the end, the green product of the black burger is probably the result of blue food colouring. The good news is that it’s coming out of you because it’s not getting absorbed into your body.

By Esther Inglis-Arkell