The Scariest Part of Burger King's "Nightmare King" Isn't What You Think

Burger King’s Halloween-themed offering, “The Nightmare King,” sits atop an alarmingly green bun. It might look like the stuff of nightmares, but the company is taking the endeavor one step further, claiming this sandwich can actually spur bad dreams.

Ingredients in the Nightmare King burger might have some negative effects on your sleep, but scientists say the Halloween meal may cause nightmares for an entirely different reason, too.

Boasting a combination of grilled beef, crispy chicken, bacon, American cheese, and mayonnaise on a bun dyed green, Burger King says its own study of 100 people who ate the Nightmare King before bed for ten days suggests it causes bad dreams.

Jose Gabriel Medina, MD, of Florida Sleep & Neuro Diagnostic Services, Inc., a neuropsychology lab in Miami, oversaw the study, which specified that subjects saw a 3.5 fold increase in nightmares over that time.

(Burger King tells Inverse it can not share the study publicly.)

Marie-Pierre St-Onge, Ph.D., who studies sleep and nutrition at Columbia University’s Institute of Human Nutrition, and Tore Nielsen, Ph.D., a psychologist who directs the Dream & Nightmare Laboratory at Montreal’s Sacré-Coeur Hospital, tell Inverse that the burger might cause nightmares for an entirely different reason. Here’s why:

The Suggestibility of the Green Bun

“I think probably these people saw the green hamburger and got traumatized or something and subconsciously it gave them fear during the night,” St-Onge jokes. “I’m thinking if I’m seeing a green bun filled with beef, crispy chicken, cheese and mayonnaise, I’m thinking ‘Wow, heart attack waiting to happen. I’m afraid.’”

St-Onge’s claim that people may have been subconsciously traumatized by the Nightmare King’s green bun isn’t as far-fetched as it sounds. Her gut reaction is echoed by Nielsen, who says that the green shade of that bun is enough to strike terror into his heart as well.

“What strikes me right out of the starting gate is the horrendous green color of this burger bun! I am probably not alone in having a visceral reaction to the color green when it comes to any kind of meat product; it virtually screams ‘bad bacteria on board!’” he says.

Nielsen adds that this gut feeling might cause people to subconsciously feel like they’ve eaten something bad or dangerous, and though this is a wild stretch — it might actually impact their dreams in that way.

“Having such a bad feeling about the burger may have carried over into their dreaming — as do many negative experiences we have when awake (eg., scary movies),” he adds.

While that’s certainly thought-provoking, Burger King makes no mention of the suggestibility of the green bun in its study. Instead, the burger franchise claims that the ingredients in the burger can affect the most restful part of the sleep cycle, rapid eye movement sleep.

Can The “Nightmare King” Affect The Sleep Cycle?

St-Onge points out that dreams, and of course, nightmares, happen during REM, a period of deep sleep. In order to cause nightmares, the burger would cause some type of arousal during this period. The company claims that their sandwich achieves this due to its carbohydrate and fat content, which lead to “an interruption” of REM in their study.

“It could be you would have more arousal and you would potentially be woken up earlier or at different times during your sleep cycle,” she says. “But whether that influences the content of your dreams….no.”

While evidence that the Nightmare King change the content of dreams remains to be seen, St-Onge says there is a way that it could cause restless sleep, if not full-blown nightmares. In a 2016 study published in The Journal of Clinical Sleep Medicine, she found that individuals who consumed diets high in saturated fat and sugar tended to have more restless hours in bed. Though importantly, this study showed this effect on low-wave sleep, a state of deep slumber but not full-blown REM.

One way this disruption happens, she explains, is through the consumption of tryptophan an amino acid better known for its presence in turkey (but things like peanut butter have high amounts too). Tryptophan helps the body make serotonin, a hormone that can often make people drowsy — but sometimes certain types of diets can make this process a bit harder.

“Your protein and carbohydrate intakes can modify the amount of tryptophan that reaches your brain that can then influence serotonin synthesis and release,” she adds.

In all, it seems like the Nightmare Burger probably won’t cause actually nightmares, but it might disturb sleep enough to make anyone who consumes it feel like they’ve been up all night in a state of terror the next day.