July 2, 2025, 5:51 pm | Read time: 7 minutes

What We Eat May Affect More Than Just Our Well-Being–It Could Influence Our Dreams A new study suggests that certain foods may be linked to nightmares, bizarre dream content, and poorer sleep quality. Notably, individuals with intolerances such as lactose intolerance report negative dream experiences more frequently. The findings raise the question of how significantly diet shapes unconscious processes during sleep.

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What and why was investigated?

The belief that a heavy meal in the evening triggers strange dreams is widespread–fueled by pop culture images like the U.S.-known comic series “Dream of the Rarebit Fiend,” where nighttime cheese dishes are regularly cited as the cause of bizarre dreams. This assumption has hardly been scientifically examined until now.

The present study aimed to clarify why people believe certain foods influence their dreams.¹ Three hypotheses were tested:

• Food-specific effects–the assumption that certain foods directly influence dreaming.
• Food-related discomfort–such as digestive issues from lactose intolerance that could disrupt dreaming.
• Sleep effects–the idea that certain eating habits impair sleep and thereby indirectly alter dreams.

The investigation aimed to identify connections between diet, eating behavior, food intolerances, and dream quality–and possibly derive new approaches for treating sleep disorders.

Study design and methods

The online survey included 1,082 psychology students (average age 20) from MacEwan University in Canada. They provided information about their diet, eating habits, known food intolerances, sleep quality, dream frequency, and mental state.

Several scientifically validated questionnaires were used:

• The Pittsburgh Sleep Quality Index (PSQI) to assess overall sleep quality,
• the Nightmare Disorder Index (NDI) to measure nightmare frequency and distress,
• the Intuitive Eating Scale-2, a questionnaire on eating behavior–particularly how much people rely on hunger and satiety cues when choosing and consuming food,
• and a special questionnaire on the subjective perception of whether certain foods or meal times influence dreams (also called “food-dependent dreaming”).

Gastrointestinal complaints (such as bloating, cramps) were also recorded in detail. The evaluation was conducted using regression analyses and structural equation models. The study examined whether specific intolerances or eating habits systematically relate to dream changes or poorer sleep.

40.2 percent reported that food affected their sleep

Overall, 40.2 percent of participants reported that certain foods affected their sleep–either positively (20.1 percent) or negatively (24.7 percent). 5.5 percent said that food had changed their dreams (“food-dependent dreaming”).

These foods could be responsible for bad dreams

Participants most frequently mentioned sweets like chocolate, cake, or ice cream, followed by dairy products like cheese, yogurt, and milk. Spicy foods like chili, heavily processed meat dishes, and carbohydrate-rich foods like bread, pasta, or rice were also often associated with negative or bizarre dreams. Overall, 31 percent said sweets negatively affected their dreams, and 22 percent cited dairy products as triggers.

Foods that improve sleep

However, foods associated with improved sleep were also mentioned. Fruits like bananas and berries, vegetables like spinach or broccoli, and herbal teas–such as chamomile or peppermint–were perceived as sleep-promoting. These were not only rarely associated with nightmares but more often linked to more pleasant or calmer dreams.

Lactose intolerance more frequently linked to poor sleep and nightmares

Participants with lactose intolerance reported poor sleep and nightmares significantly more often. This relationship was significantly mediated by gastrointestinal complaints–such as nighttime bloating or cramps. Food allergies and gluten intolerance were also more common among those who reported changes in their dreams due to certain foods.

Another finding: People with healthier eating habits (e.g., high alignment between body needs and food choices, less evening eating) more often reported vivid or positive dreams. In contrast, nightmares were more common among those with unhealthy eating habits–such as evening snacking, low reliance on hunger and satiety signals, or frequent eating without physical hunger. Psychological stress (depression, anxiety) also negatively affected dream experiences.

What is the significance of the results?

The study provides comprehensive empirical evidence for the first time that diet can influence nighttime experiences–especially in people with existing food intolerances. The repeated mention of dairy products and the statistically significant link between lactose intolerance, gastrointestinal complaints, and nightmares support the hypothesis that physical discomfort at night can alter dream experiences through the autonomic nervous system.

Sleep and dreams can be positively or negatively influenced by food

Unhealthy eating patterns–especially late-night eating–are associated with an increased frequency of nightmares and negative dream tones. Conversely, health-conscious, intuitive eating correlates with more frequent and positive dream perceptions.

These connections could play a role in the prevention or non-pharmacological treatment of sleep disorders and nightmares in the future–especially for patients with known food intolerances. At the same time, the study shows that many people attribute their dreams to specific foods that are physiologically unremarkable–which could indicate cultural influences or misinterpretations.

Study classification and possible limitations

The study is based on a large, well-documented sample and covers a wide range of influencing factors–including diet, health, sleep quality, and psychological stress. Methodologically, it is convincing with valid measurement tools and differentiated statistical analyses. Nevertheless, it is a cross-sectional self-report study, prone to errors or misjudgments, and does not allow causal statements.

The results show correlations–whether diet influences dreams or vice versa, certain dream types shape eating behavior remains open. Additionally, only students were surveyed, which limits generalizability.

Lack of inclusion of cultural perceptions

Another limitation is the lack of inclusion of cultural perceptions that shape whether and which foods are perceived as “dream-altering.” The increased societal focus on nutrition topics in recent years–such as through social media or the pandemic–could also have influenced self-assessments.

Despite these limitations, the study provides a valuable impetus for future experimental research. In particular, the connection between lactose intolerance, gastrointestinal symptoms, and nightmares appears plausible and clinically relevant.

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Conclusion

According to the study, dreams and sleep quality seem closely linked to diet, individual intolerances, and eating behavior. Dairy products and sweets are particularly often associated with negative dream content. People with lactose intolerance or food allergies report nightmares more frequently–an effect partly mediated by gastrointestinal complaints.

Moreover, healthy eating habits are associated with more positive dream experiences, while unfavorable eating behavior–such as evening snacking–can promote nightmares. Thus, the study provides new, empirically based evidence of a long-suspected connection–and opens up perspectives for the targeted use of diet in sleep-related therapies.