A research team from Université de Montréal surveyed 1082 students about their sleep, dreams, eating habits and known food sensitivities. The goal was to test these three ideas.
- Some foods might affect dreams directly.
- Food-triggered gut symptoms might spill into sleep and dream content.
- Dietary habits might worsen sleep which then colours dreams.
Dairy and nightmares
About 40% of students felt that certain foods affected their sleep. A smaller group, 5,5%, felt foods altered their dreams. When people named culprits for worse sleep or disturbing dreams, desserts and sweets came first, dairy was a close second. What made dairy interesting was the link to lactose intolerance. Students who reported lactose intolerance also reported poorer sleep and higher nightmare scores, and the statistics suggested this was largely mediated by gastrointestinal symptoms such as bloating, cramps and gas at night.
As lead author Dr. Tore Nielsen put it: “Nightmare severity is robustly associated with lactose intolerance and other food allergies. These new findings imply that changing eating habits for people with some food sensitivities could alleviate nightmares. They could also explain why people so often blame dairy for bad dreams!”
Timing matters too
Eating close to bedtime was associated with more negative dream tone and higher nightmare scores. More evening eating, more gut discomfort, and less reliance on internal hunger and fullness cues all pointed in the same direction: worse sleep and more unpleasant dreams. On the flip side, healthier patterns, including less evening eating and choosing foods that fit the body’s needs, were linked with better dream recall without the negativity.
What this means for cyclists
Many riders take in recovery foods late in the day, especially after evening sessions or a long commute home. If you are lactose intolerant, a whey shake or a bowl of yoghurt at 21:30 could be a double hit: tummy trouble that fragments sleep, and a higher chance of waking from a bad dream. Fragmented sleep also means poorer recovery and lower training readiness the next day.
And it’s good to keep in mind that this was a student sample, mainly self-report, so it cannot prove cause and effect. “We need to study more people of different ages, from different walks of life, and with different dietary habits to determine if our results are truly generalizable to the larger population,” said Nielsen.
Simple tweaks for better sleep and calmer dreams
If this research resonated with your own experience, there are a few dietary tweaks you could try to see if calmer nights and better recovery are possible.
- Move calories earlier. Aim to finish your main meal 2–3 hours before bed, especially after evening training. Keep any late snack light.
- If you notice that eating dairy close to bedtime often causes bad dreams and interrupted sleep, try switching to lactose-free milk or plant-based protein alternatives.
- Enjoy desserts and very spicy meals at lunch or earlier in the day.
- Listen to hunger cues. Do your best to avoid skipping meals throughout the day so you are not chasing cravings late at night.
- If you aren’t sure what the culprit is, try keeping a sleep journal for a week where you log how your sleep felt, what kind of dreams you had, and what you were eating late in the day.
