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Next week is Halloween, and Burger King is celebrating this spooky time in style with a terrifying new burger. That’s what I always want from a sandwich.

And if you’ve seen this thing… it’s certainly enough to scare your intestines at least. It’s thick-cut bacon layered on fried chicken, layered on a cheeseburger, all piled onto a fluorescent green bun. I don’t know why...let’s just move on.

You might remember the limited edition black-bun whopper they did a few years ago, but this time, they’re calling their creation the Nightmare King. And they say that that name isn’t hyperbolic. They’re arguing that the burger can literally give you scary dreams — and that they did science to back that claim up.

But we here at SciShow are not entirely convinced the burger is really nightmare-inducing — not more than any other big, weirdly-colored, late-night meal would be, anyway. According to their press release, and yes we’re really doing this right now, Burger. King commissioned sleep scientists to study the effects eating the burger had on 100 subjects’ dreams.

For 10 nights, some of them consumed the ghastly green burger before they went to bed, and then they all had their heart rate, breathing, and brain activity monitored while they slept. And reportedly, the subjects who ate the burger experienced three and a half times more nightmares. Why are you advertising this!?

Even if eating the burger did correspond with more nightmares, it’s definitely not clear that it was the burger’s unique mix of ingredients that caused them, as the sleep researcher quoted in the press release claims. So basically, it seems like a clever if dubious marketing campaign… and the kind of science that gives scientists nightmares. But it does beg the question of whether this kind of thing is even possible — whether eating a particular food can affect your dreams.

And according to the science have to date… maybe? Psychologists often define nightmares as vivid bad dreams, especially ones that wake you up. They usually happen during REM sleep, the phase when dreaming happens and when you’re closest to being awake.

And because they do so often wake you up, you’re more likely to remember them. Generally, they’re believed to be caused by stress, anxiety, irregular sleep, medications, and disorders like PTSD or depression. But, there has been some research which suggests that eating particular foods or eating at all before bed can disturb your sleep and maybe even cause upsetting dreams.

Most of this research has been small studies or case studies, but there was pretty large one conducted in 2015. This study, published in the journal Frontiers in Psychology, looked at 382 undergraduates, who were asked to complete several surveys about their sleep patterns, eating habits, and dreams over the previous two to four weeks. The researchers found that 17.8% of the participants reported that their dreams were affected by eating particular foods or by eating late at night.

Since the study was retrospective rather than experimental, the data don’t confirm that the foods eaten by the participants actually caused nightmares. But clearly, the participants thought they did, and there are several reasons why that might be. The first is that some foods really are to blame.

Eating spicy food before bed can raise your body temperature, for example; and studies have linked higher temperatures to poor sleep and even bizarre dreams. Food-related discomfort — like acid reflux — has also been suggested as a cause of bad dreams, either directly or as a result of worse sleep. And the foods that are often reported as causing nightmares do tend to be ones that make your stomach upset, like spicy things and dairy.

Of course, it might not be a specific food. One effect of eating is that it can kick your cells’ activity into high gear. So eating before bed in general can increase the activity of your cells, including your brain cells, which some researchers think might lead to more vivid — and possibly scary — dreams.

But here’s where it gets interesting. There’s a lot of folklore out there about foods that can make you have nightmares. So it could be that there’s a nocebo effect at play here, where people’s negative expectations cause something harmless to have a negative effect.

In other words, just thinking a food might give you scary dreams could be enough to make you have them. Or, it could all just be a case of mistaken identity. If you have nightmares after eating something you believe is nightmare-inducing, you might attribute your dreams to that food, even if there is no real cause-and-effect link.

So even if we assume that the Burger King sleep study participants really did have more nightmares… well, any of these explanations could get at why. There’s no denying that the burger’s layers of fried chicken, beef, cheese, and bacon could be enough to cause intestinal distress. Or, if the participants just happened to have weird dreams because they were away from their own beds and being videoed while hooked up to all kinds of machines… well, it’s not so unreasonable to assume that they might misattribute those nightmares to the strange burger they’d just been required to eat.

So, sure, it’s not totally bonkers to think that demolishing this green-bunned burger right before bed might give you nightmares. And if you want give it a try, I’m not gonna judge you! I will judge myself though, when I do this, which I probably will.

But if you do have bad dreams afterwards, that might have more to do with your expectations or our upset tummies than it being some weird, perfect combination of scare-inducing meats. Thanks for watching this episode of SciShow News! And a special thank you to Matthew Brant, our Patreon President of Space!

Matthew Brant, aren’t you so glad you support us so that we can make important journalism like this episode? Honestly though, we cannot make SciShow without support of our Patrons. If you want to support SciShow on Patreon, please do that, head on over to Patreon.com/SciShow. [♪ OUTRO ].