From Scrooge to science: how dairy might disrupt your sleep and dreams

Ebenezer Scrooge tried to wave away the ghost of Jacob Marley by blaming the apparition on “an undigested bit of beef … a crumb of cheese”. Charles Dickens might have been writing fiction, but the idea that late-night dairy can warp dreams has now gained scientific support.

Researchers in Canada surveyed 1,082 university students about their eating habits, sleep patterns and dreams.  Remarkably, 40% reported that certain foods affected their sleep. Of that group, 20% blamed dairy – suggesting that Scrooge’s midnight cheese might have had more of an impact than he realised.

Just 5.5% believed food changed their dreams, but among those respondents dairy again loomed large, second only to sugary desserts as a perceived trigger for bizarre or disturbing dreams.

The researchers asked about everything from nightmare frequency to food allergies and intolerances. A clear pattern emerged: participants who reported lactose intolerance were significantly more likely to have frequent nightmares. And the link was strongest in people who also experienced bloating or cramps.

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Statistical modelling suggested the stomach distress partly explains the bad dreams. In other words, food that keeps the gut churning can also set the imagination spinning.

That gut–brain route makes physiological sense. Abdominal discomfort can jolt sleepers into lighter stages of sleep where vivid or negative dreams are most common. Inflammation and spikes in cortisol (a stress hormone) triggered by digestive upset may further shape the emotional tone of dreams, especially by amplifying anxiety or negativity.

Earlier work backs the idea. A 2015 survey of Canadian undergraduates found that nearly 18% linked what they ate to their dreams, with dairy the top suspect, while a 2022 online study of 436 dream enthusiasts reported that people who ate more sugary snacks remembered more nightmares.

The new study from Canada echoes a wider literature on diet and sleep. Diets rich in fibre, fruit and vegetables are associated with deeper, more refreshing sleep, whereas meals high in saturated fat and sugar predict lighter, more fragmented rest.

Eating late in the evening has been tied to poorer sleep quality and to an “evening chronotype” (that is, night owls), itself linked to nightmare frequency.

If future work confirms the cheese–nightmare connection, the implications could be practical. Nightmares affect about 4% of adults worldwide and are particularly common in post-traumatic stress disorder.

Drug treatments exist but carry side-effects. Adjusting the timing or composition of evening meals, or choosing low-lactose dairy options, would be a far cheaper, lower-risk intervention.

Gut-friendly diets such as the Mediterranean diet are already being explored for mood disorders; nightmares may be another frontier for nutritional psychiatry.

What the research can’t prove

That said, the new findings come with caveats. The sample was young, mostly healthy psychology students filling out online questionnaires. Food intake, lactose intolerance and nightmare frequency were all self-reported, so “recall biases” (inaccurate memory) or the power of suggestion could inflate the associations.

Only 59 participants believed food influenced their dreams, so small-number effects (unreliable results from too few data) are possible. And a survey can only reveal associations – it can’t prove that cheese causes bad dream.

Cheese keeps cropping up in nightmare stories, and people who struggle to digest dairy report the worst of it. Scientists still have to match meal diaries, gut clues and lab-monitored dreams to prove the link. In the meantime, try eating earlier or choosing low-lactose options. Your stomach – and your dreams – may calm down.

Timothy Hearn does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.