Does food cause nightmares? What studies show about cheese, sugar and spicy food

Cheese and dairy: the food blamed most in 2015

The idea is old:

Both papers are named after Dream of the Rarebit Fiend, a comic strip from the early 1900s in which people have bizarre and disturbing dreams after eating Welsh rarebit, a dish of melted spiced cheese on toast.

Two surveys of students by the same research group asked people which foods they blame.

In the 2015 survey, spicy food came second for disturbing dreams (named by 19% of the students who gave an example), and sweets were blamed more often for bizarre dreams (31%) than for disturbing ones (13%).

In an online survey published in 2025, the same research group asked 1,082 university students about food, sleep and dreams. 24.7% said certain foods worsened their sleep and 20.1% that foods improved it, while 5.5% said foods or eating late affected their dreams. Of the foods they named for more disturbing dreams, desserts or sweets made up 31% and dairy 22% (about 30% and 21% across all the dream changes they named).

You may have read that a cheese study found different cheeses bring different dreams. That study was never published in a peer-reviewed journal:

The 2015 paper notes that a 2005 cheese-and-dreams study by the British Cheese Board, widely reported in the media, was never published in a peer-reviewed journal, and that very little is known about how it was done.

Why food may get the blame

These surveys ask people what they remember and believe. Students who blamed food did differ from the others:

Students in the 2015 survey who said food or eating late affected their dreams also reported more frequent and more distressing bad dreams, poorer sleep and more coffee than the other students. Once the authors allowed for whether students said eating late affected their dreams, the groups no longer differed on disturbing dreams, coffee, hours of sleep or sleep dissatisfaction, though difficulty falling asleep and daytime dysfunction still differed.

But asking people is a weak test of cause and effect, and the authors say so themselves:

The authors call these results exploratory: they rest on students’ own memories and show associations, not causes. They put forward four explanations to test: particular foods really do affect dreams; discomfort from a food intolerance disturbs sleep and dreams; people take on folklore, such as old stories about cheese and bad dreams; or people blame a food for a dream it did not cause.

The 2025 survey looked at food intolerance, one of those explanations:

In that survey, higher scores on a questionnaire about how often nightmares happen and how much they disturb people went with reported lactose intolerance and food allergy, and the lactose link ran through how bad people’s gut symptoms were. Evening eating and stomach symptoms went with more nightmares and more negative dreams.

The authors write that their findings are essentially correlational, so it remains unclear whether diet causes dream changes, whether dreams affect what people eat, or whether a third factor affects both.

So a fair reading is: if a food upsets your stomach, it may also upset your sleep and the dreams you remember. That is a long way from "cheese causes nightmares".

Sugar and spicy food: what the lab studies measured

Two small sleep-lab studies looked at sugar and spicy food. Both measured sleep, not dreams.

In a 2016 sleep-lab study of 26 normal-weight adults, on a day they chose their own food, a higher share of that day’s energy from sugar was associated with more arousals from sleep that night. The authors say the role of diet in sleep still needs to be tested.

In a 1992 sleep-lab study of six young, healthy men, Tabasco sauce and mustard taken with the evening meal reduced deep (slow-wave) and stage 2 sleep, increased total time awake, and raised body temperature during the first sleep cycle.

Six people is a very small study, and it measured sleep stages, not dreams. If your evening sweets are chocolate, our sister site caffeinetime.today lists the caffeine in dark, milk and white chocolate.

If you think the timing of your evening meal is the problem rather than the food, see what studies say about eating before bed.

What is known to bring on nightmares

The NHS lists common causes of nightmares and night terrors as being very tired or unwell; sudden noises at night or needing to pee during the night; and something that has frightened you or made you stressed, anxious or worried. Other causes it lists include certain medicines, such as antidepressants, and some health conditions.

Food is not on that list. What the NHS suggests trying instead:

For nightmares, the NHS suggests trying a relaxing bedtime routine, dealing with things that might be causing stress or anxiety, and keeping a sleep diary to help identify any causes.

A printable sleep diary has room for notes. If you suspect a food, write down what you ate in the evening and when, next to the nights you had bad dreams. After two weeks you can see whether the two really go together. If a bad dream woke you and you can't get back to sleep, see getting back to sleep after waking in the night.

When nightmares are worth talking to a doctor about

The NHS advises seeing a GP if you are having regular nightmares that are affecting your sleep and everyday life. It says cognitive behavioural therapy (CBT) can help adults who have frequent nightmares, and that for nightmares caused by a traumatic event a GP may recommend psychological treatment such as counselling.