A new study has reignited an age-old belief: what you eat before bed might haunt your dreams. Researchers from the University of Montreal have found evidence suggesting that certain foods—particularly dairy and sugary treats—could be linked to nightmares and disturbed sleep, especially among those with lactose intolerance.
Published in the journal Frontiers in Psychology, the study surveyed over 1,000 university students in Alberta, Canada, on their eating habits, food sensitivities, sleep patterns, and dream experiences. About 25% of participants said some foods worsened their sleep, while just over 20% reported the opposite.
Among those who experienced nightmares after eating, 31% blamed desserts and sweets, 22% cited dairy products, 16% mentioned meats, and 13% pointed to spicy foods. Notably, lactose intolerance emerged as the most commonly reported condition tied to poor sleep, with 30% of those with dietary-related sleep issues identifying as lactose intolerant.
Lead researcher Professor Tore Nielsen said the findings make sense. “Nightmares are worse for lactose-intolerant people who suffer severe gastrointestinal symptoms and whose sleep is disrupted,” he noted. “This makes sense because we know that other bodily sensations can affect dreaming.”
Nielsen referenced earlier research showing that external stimuli—such as sounds, light, and physical pressure—can shape dreams. This suggests that internal discomfort, like bloating or cramping, could trigger more vivid or disturbing dream content. In fact, a 2005 study by the same researcher found increased emotional intensity in dreams during episodes of abdominal cramping.
The timing of meals also matters. Late-night snacking or eating close to bedtime was linked to what researchers described as an “eveningness chronotype”—or “night owl” tendencies—which previous studies have associated with a higher likelihood of nightmares.
While the study does not confirm causality, Nielsen said the findings point to the need for more rigorous, controlled experiments. “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,” he said.
Not all foods were deemed problematic. Around 18% of people who regularly ate fruit reported improved sleep, as did 12% of vegetable-eaters and 13% of herbal tea drinkers.
As scientists call for more research across age groups and lifestyles, the findings breathe new life into the old warning: be mindful of what’s on your plate—your dreams may depend on it.
