FACT CHECK: Does cheese cause nightmares? Here’s what the science actually says

For years, popular culture has entertained the idea that eating cheese before bed might lead to bizarre or unsettling dreams. From cartoons like Dream of the Rarebit Fiend to internet folklore, cheese has often been blamed for nighttime horrors. Recently, this notion resurfaced in the headlines after a new study reignited the debate—suggesting there might be some scientific basis behind the age-old belief.

Media outlets didn’t hesitate to dramatize the story. NBC News asked, “Can cheese turn your dreams into nightmares?” while People.com reported, “Eating Cheese Before Bed May Cause Nightmares, Study Finds.” IFLScience put it bluntly: “We Regret To Inform You That Cheese Really Can Cause Nightmares.” Other outlets, including Gizmodo and The Independent, ran similarly eye-catching headlines.

These articles appeared after the journal Frontiers in Psychology released a press statement with the title: “Cheese may really be giving you nightmares, scientists find.” In it, researchers suggested that consuming dairy, particularly among people with lactose intolerance, might be associated with more disturbing dreams. But how accurate are these bold headlines? And what exactly did the study find?

The research, led by Tore Nielsen of the Université de Montréal, aimed to explore the connections between food, sleep quality, and dream experiences. Building on earlier work that hinted at a link between dietary habits and sleep patterns, the new study focused specifically on the question of whether certain foods might influence dream content—especially nightmares.

To examine these questions, the researchers surveyed over 1,000 undergraduate students at MacEwan University in Canada. Participants were asked about their dietary habits, sleep quality, dream recall, and the perceived influence of food on their sleep and dreams. The survey also gathered detailed information on their health status, psychological well-being, and any food allergies or intolerances they might have.

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About a third of participants reported some form of food sensitivity, with lactose intolerance being one of the most common. Nearly 16% said dairy products, such as cheese or milk, made their sleep worse, and over 20% blamed dairy for disturbing or bizarre dreams. Overall, just over 5% of participants said they had personally noticed that eating certain foods affected their dreams, a phenomenon the researchers labeled “food-dependent dreaming.”

To better understand these perceptions, the researchers asked those participants to identify which food groups they believed influenced their dreams. Sweets and desserts topped the list, followed by dairy. Most people who reported food-dependent dreaming said it led to more vivid, strange, or disturbing dreams. Fewer participants said that food led to pleasant or lucid dreams.

The researchers then examined whether these subjective reports were supported by broader patterns in the data. They found that participants who reported food-dependent dreaming also tended to experience more frequent nightmares. Additionally, nightmares were more common among people with lactose intolerance and food allergies. Importantly, statistical analyses showed that this relationship could often be explained by the presence of gastrointestinal symptoms, such as bloating or stomach pain, which might disrupt sleep and contribute to more intense or negative dream experiences.

To explore this idea further, the researchers used a method called mediation analysis. This allowed them to test whether gastrointestinal distress might be the link between lactose intolerance and nightmares. The results supported this idea: people with lactose intolerance were more likely to have stomach discomfort at night, which was in turn associated with more frequent and intense nightmares. The researchers also found that people who ate late at night—especially those who reported snacking after dinner or waking up to eat—tended to have poorer sleep and more disturbing dreams.

Notably, the researchers did not find that simply eating dairy caused nightmares in everyone. Rather, the effects seemed to be most pronounced among those with lactose intolerance or food allergies. This suggests that the popular belief about cheese and bad dreams may have a kernel of truth, but the real story is more nuanced. It’s not that cheese itself is inherently nightmare-inducing—it’s that for some people, consuming dairy can lead to physical discomfort during sleep, which may influence the emotional tone and vividness of their dreams.

The study also supported a broader idea that diet and sleep are linked in meaningful ways. Participants who reported healthier eating habits tended to have more positive or vivid dreams, while those who ate more sweets or consumed food late at night were more likely to experience nightmares or poor sleep quality. The research adds to a growing body of evidence suggesting that dietary choices can shape not just our waking health, but our experiences during sleep as well.

But there are some limitations to consider. The study relied on self-reported data, which can be influenced by memory biases or cultural beliefs. The participants were all undergraduate students from a single Canadian university, which may limit how well the findings apply to other groups. The data were also correlational, meaning the researchers could not determine whether food caused the changes in dreams, or whether some third factor—such as stress or general health—was influencing both.

Another consideration is that cultural beliefs and folklore may shape how people interpret their dream experiences. The idea that cheese causes nightmares has been around for over a century, popularized in part by artists like Winsor McCay. The researchers note that such beliefs may lead people to blame dairy for bad dreams even when other factors are at play. This is known as the misattribution hypothesis.

In short, it is not accurate to say that cheese causes nightmares. To determine whether cheese actually causes nightmares, scientists would need to conduct a controlled experiment rather than a survey. This would involve randomly assigning participants to eat cheese or a non-dairy control food before bed, ensuring all other factors like sleep environment and timing are held constant.

But the results also shouldn’t be entirely dismissed, either. The study provides evidence of a link between dairy and nightmares that warrants additional investigation.

“We need to study more people of different ages, from different walks of life, and with different dietary habits to determine if our results are truly generalizable to the larger population,” Nielsen said in the press release. “Experimental studies are also needed to determine if people can truly detect the effects of specific foods on dreams. We would like to run a study in which we ask people to ingest cheese products versus some control food before sleep to see if this alters their sleep or dreams.”

The study, “More dreams of the rarebit fiend: Food sensitivity and dietary correlates of sleep and dreaming,” was authored by Tore Nielsen, Jade Radke, Claudia Picard-Deland, and Russell Arnold Powell.