A viral social media post claiming scientists have “confirmed” that cheese causes nightmares racked up more than 9.5 million views on a single platform in mid-2025, resurrecting a belief that traces back over a century to an early 1900s comic strip called Dream of the Rarebit Fiend, in which characters blamed their bizarre nightmares on Welsh rarebit, a spicy melted cheese dish eaten right before bed. The persistence of this idea, jumping from a satirical comic strip to a genuine peer-reviewed study more than a hundred years later, says something interesting about how food folklore and scientific research can end up occupying the same cultural space, even when the actual evidence connecting the two is considerably more nuanced than either the comic strip or the viral headline suggested.
The study actually responsible for this latest wave of headlines, titled “More Dreams of the Rarebit Fiend: Food Sensitivity and Dietary Correlates of Sleep and Dreaming,” was published July 1, 2025, in the journal Frontiers in Psychology by researchers including Tore Nielsen, a psychiatry professor at the University of Montreal, building directly on an earlier 2015 study that had examined the same folk belief. Researchers surveyed 1,076 undergraduate students at MacEwan University in Canada about their dietary habits, sleep quality, dream recall, food sensitivities, and psychological wellbeing. The headline statistic circulating on social media, that 25 percent of participants who reported food-related dreams identified dairy as a cause, is accurate as far as it goes, but it obscures a critical detail buried much deeper in the same study: only 5.5 percent of the full 1,076 participants, just 59 people total, reported that food affected their dreams at all in the first place, meaning the widely repeated 25 percent figure describes a subset of a subset, not a finding that applies to the general population of cheese eaters.
Where Did the Cheese and Nightmare Belief Come From?
The specific pairing of cheese with disturbing dreams has circulated in Western popular culture for well over a century, memorably captured in the Dream of the Rarebit Fiend comic strip that gave the 2025 study its punning title. Cultural food-and-dream associations tend to persist through repeated anecdotal reinforcement, a person eats a heavy or unusual meal, has a memorable bad dream that night, and attributes causation to the meal rather than to any of the dozens of other factors that could plausibly explain a single night’s dream content. This pattern of repeated anecdote hardening into accepted folk wisdom, well before any rigorous testing occurs, describes a huge share of enduring food myths, and cheese-and-nightmares offers a particularly durable example.
What the New Study Actually Investigated
The 2025 study built directly on a 2015 predecessor examining what researchers call “food-dependent dreaming.” Researchers distributed a detailed online survey to more than a thousand university students, gathering self-reported information on dietary habits, sleep quality, dream recall frequency, perceived food sensitivities including lactose intolerance, and overall psychological wellbeing.
Participants were asked whether they believed specific foods affected their sleep or dream content, and if so, which foods and in what way. This is a critical design detail: the entire study relies on retrospective self-report through an online survey, with no direct, objective monitoring of participants’ actual sleep architecture, dream content, or food intake during the study period itself.
Did the Study Actually Show That Cheese Causes Nightmares?
This is the question where careful reading matters enormously, and where most viral social media coverage failed the readers who shared it. The study is observational and correlational, built entirely on self-report survey data rather than a controlled experiment in which researchers actually fed participants cheese under monitored conditions and then measured resulting dream content. A study design like this can identify an association, in this case, a documented association between self-reported lactose intolerance severity and self-reported nightmare frequency, intensity, and associated distress, but it cannot establish that cheese consumption directly causes nightmares in a mechanistic, cause-and-effect sense. Of the 1,076 total respondents, only 5.5 percent, 59 people, reported that food affected their dreams in any way; among just that small subgroup, desserts and sweets were blamed most often, accounting for 31 percent of food-related disturbing dreams, with dairy close behind at 22 to 25 percent depending on how the specific survey question was framed. This means the sensational “cheese causes nightmares” framing that dominated headlines describes, at its statistical core, a pattern observed in a subgroup of fewer than 60 people out of more than a thousand surveyed, a finding that may well point toward something real and worth investigating further, but that falls dramatically short of the sweeping, population-wide claim implied by viral headlines describing the finding as “confirmed.”
How Food Could Potentially Affect Sleep and Dreams
The researchers themselves proposed a specific, physiologically plausible mechanism rather than any mysterious or unexplained connection: participants with more severe self-reported lactose intolerance also reported more frequent and more disturbing nightmares, and the study’s authors suggested this connection likely runs through gastrointestinal discomfort rather than any direct chemical effect of dairy on brain activity or dream content.
Nighttime digestive upset, bloating, cramping, or gas resulting from lactose intolerance can plausibly cause brief awakenings during sleep, sometimes called micro-arousals, and dream researchers have long observed that awakenings during or near REM sleep, the sleep stage most associated with vivid dreaming, tend to produce more memorable and more easily recalled dream content, including a higher likelihood of that content skewing toward disturbing or emotionally negative themes. This proposed mechanism, digestive discomfort disrupting sleep architecture rather than dairy exerting some direct neurological effect, is considerably more mundane than the folklore version of this claim, but it is also considerably more scientifically grounded.
Why Cheese May Be an Interesting Food to Study
Cheese sits at an interesting intersection of nutritional properties that make it a reasonable candidate for this kind of research question, independent of whether the current evidence fully supports strong causal claims. Its fat content can slow digestion, its lactose content directly triggers digestive symptoms in people with lactose intolerance, a condition estimated to affect a substantial share of the global adult population, and different cheese varieties vary considerably in lactose content depending on their aging and fermentation process.
None of these properties has been demonstrated to directly and specifically cause nightmares through a well characterized biological mechanism; the current evidence points toward digestive discomfort as a plausible intermediate pathway rather than establishing any direct neurochemical link between cheese consumption and dream content itself.
Why Dreams Are Difficult to Study Scientifically
Dream research carries inherent methodological challenges that limit how confidently any single study, including this one, can support strong causal claims. Dream recall itself is famously unreliable and varies enormously between individuals and even within the same individual from night to night, meaning self-reported dream content is always filtered through the imperfect and selective process of memory.
Studies relying on retrospective surveys, like this one, ask participants to recall and characterize patterns over an extended period rather than capturing dream content immediately upon waking, introducing further opportunity for memory distortion or unconscious confirmation bias, where a participant who already believes cheese affects their dreams may be more likely to notice and remember instances that seem to confirm that belief.
Laboratory-based sleep studies, which can objectively monitor sleep stages and wake participants at controlled intervals to capture dream reports in real time, offer more rigorous data but are expensive, resource-intensive, and consequently limited to far smaller sample sizes than an online survey can reach, creating an inherent tradeoff between methodological rigor and sample size that dream researchers must navigate in every study design choice.
What About Other Foods and Nightmares?
The same 2025 study found that desserts and sweets were actually blamed more frequently than dairy among the small subgroup reporting food-dependent dreaming, accounting for 31 percent of implicated foods compared to dairy’s 22 to 25 percent. Separate, smaller research efforts, including a widely publicized but non-peer-reviewed industry study conducted by a commercial sleep products company involving just 30 participants, have examined spicy foods, heavy late-night meals, and specific cheese varieties in relation to sleep disruption and dream content, though these smaller and less rigorously designed studies deserve considerably more caution than the peer-reviewed Frontiers in Psychology research discussed above.
The more consistent and better-supported finding across this body of research is that eating late at night, eating when not genuinely hungry, and heavy meals close to bedtime were all associated with poorer overall sleep quality and higher rates of disturbing dreams, independent of any specific food type, while diets richer in fruits, vegetables, and herbal teas were associated with better sleep quality and fewer nightmares.
Should People Stop Eating Cheese Before Bed?
For someone without diagnosed lactose intolerance or a personal, consistently observed pattern connecting dairy consumption to disrupted sleep, the current evidence does not support broad dietary restriction based on this single study. For someone who does experience lactose intolerance symptoms and has independently noticed a personal pattern of worse sleep or more disturbing dreams following dairy consumption, adjusting the timing or quantity of dairy intake before bed represents a reasonable, low-cost experiment to test that personal observation, though it should be understood as addressing likely digestive discomfort rather than acting on a proven direct cheese-to-nightmare mechanism.
Anyone experiencing persistent, severe, or worsening sleep disruption, regardless of suspected food triggers, is better served discussing the broader pattern with a healthcare provider rather than relying solely on a single dietary elimination based on a viral headline.
How to Read Viral Food and Health Studies
A useful checklist for evaluating the next viral food-and-health claim starts with locating the original peer-reviewed study rather than relying on secondhand summaries or social media posts. Determining whether the study was randomized and controlled or purely observational fundamentally changes how much weight a causal claim deserves.
Checking the actual sample size behind a headline statistic, as this cheese study vividly illustrates, since a percentage describing a small subgroup within a larger sample can create a dramatically inflated impression of a finding’s scope and applicability. Considering whether the reported outcome relies on self-report versus objective measurement affects how much confidence the finding can support.
Checking whether the finding has been replicated in independent research, and considering funding sources and potential conflicts of interest, particularly for research conducted or promoted by companies with a commercial interest in the outcome, round out a reasonably thorough evaluation framework that would have caught most of what the viral cheese headlines got wrong.
The cheese-and-nightmares story that dominated social media in mid-2025 is a genuinely useful case study in exactly how a modest, carefully caveated research finding, a documented association between self-reported lactose intolerance severity and nightmare frequency in a subgroup representing just 5.5 percent of survey respondents, can transform through repeated retelling into a sweeping, “confirmed” causal claim that the original researchers never actually made.
The underlying science here is neither a debunking of the century-old cheese folklore nor a vindication of it; it is a plausible, physiologically grounded hypothesis, digestive discomfort disrupting sleep and dream recall, that deserves further, more rigorous investigation before anyone treats it as an established fact about how cheese affects the sleeping brain.
FAQ
Q: Can cheese really cause nightmares?
A: A 2025 study found an association between lactose intolerance severity and nightmare frequency in a small subgroup of participants, but the research does not prove cheese directly causes nightmares in the general population.
Q: What did the recent cheese and dreams study find?
A: Researchers surveying 1,076 university students found that only 5.5 percent reported food affecting their dreams at all, with dairy and sweets most commonly blamed among that small subgroup.
Q: Does eating cheese before bed affect sleep?
A: For people with lactose intolerance, dairy consumption before bed may cause digestive discomfort that disrupts sleep, though this effect is not universal and depends on individual digestive sensitivity.
Q: Can other foods cause vivid dreams?
A: Yes. The same study found desserts and sweets were blamed even more often than dairy for disturbing dreams among participants who reported food affecting their sleep.
Q: Why are dreams difficult to study?
A: Dream recall is inherently unreliable and subjective, and most research relies on self-reported survey data rather than objective, real-time monitoring of sleep and dream content.
Q: Can late night eating affect sleep quality?
A: Yes. Research consistently links eating late at night or when not hungry to poorer sleep quality and more frequent disturbing dreams, independent of any specific food type.
Q: Is there scientific evidence that dairy causes nightmares?
A: Current evidence shows an association, likely explained by digestive discomfort in lactose-intolerant individuals, rather than proof of a direct causal link between dairy and nightmares broadly.
Q: Should people avoid cheese before bed?
A: Only people who have personally noticed a consistent pattern between dairy and disrupted sleep, particularly those with lactose intolerance, have a clear reason to consider adjusting their evening dairy intake.