Researchers wanted to know if eating a healthier diet helps college women sleep better at night. They looked at what over 300 female students ate and how well they slept. Surprisingly, eating a generally healthy diet didn’t seem to make a big difference in sleep quality. However, the study did find something interesting: eating more fruit was linked to better sleep, but eating more of certain healthy fats called PUFAs was actually connected to worse sleep. This suggests that some specific foods might matter more for sleep than just following a healthy diet overall.

The Quick Take

  • What they studied: Whether eating a healthy diet (measured by a scoring system called AHEI) helps female college students sleep better at night
  • Who participated: Female university students; the exact number wasn’t specified in the abstract, but the study included enough participants to look for patterns in their eating and sleeping habits
  • Key finding: Overall diet quality didn’t predict sleep quality, but two specific foods stood out: eating more fruit was linked to better sleep, while eating more polyunsaturated fats (healthy fats found in fish and nuts) was surprisingly linked to worse sleep
  • What it means for you: If you’re struggling with sleep, focusing on eating more fruit might help. However, this is just one study, and more research is needed before making major changes to your diet. Talk to a doctor or nutritionist before making big dietary changes, especially if you have sleep problems.

The Research Details

This was a cross-sectional study, which means researchers took a snapshot in time of what female college students were eating and how well they were sleeping, rather than following them over months or years. The researchers used a detailed food questionnaire to calculate each student’s diet quality score using something called the Alternative Healthy Eating Index (AHEI). They also asked students about their sleep quality and collected information about other factors that might affect sleep, like how much exercise they got, how many calories they ate, and their family’s income level.

The AHEI is a scoring system that rates diet quality based on eating more of certain healthy foods (like fruits, vegetables, and whole grains) and less of unhealthy foods (like red meat and sugary drinks). The researchers looked at whether students with higher AHEI scores (healthier overall diets) also reported better sleep quality. They also looked at individual food groups separately to see if specific foods mattered more than the overall diet score.

This research approach is useful because it can quickly show whether two things are connected (like diet and sleep). However, because it’s just a snapshot, it can’t prove that one thing causes the other. The researchers also tried to account for other factors that might affect sleep, like exercise and income, which makes the results more reliable. Looking at individual food groups separately was important because it revealed that some specific foods might matter for sleep even when the overall diet score didn’t.

This study has some strengths: it looked at many students at once, measured diet carefully using a detailed questionnaire, and tried to account for other factors that might affect sleep. However, there are also limitations: the study only included female students, so results might not apply to men; it was a snapshot in time rather than following students over time; and the researchers couldn’t prove that food actually causes better or worse sleep, only that they’re connected. The fact that the overall diet score didn’t matter but specific foods did is interesting but needs more research to understand why.

What the Results Show

The main finding was surprising: when researchers looked at overall diet quality using the AHEI score, there was no meaningful connection between how healthy students’ diets were and how well they slept. This was true even after the researchers adjusted for other factors like exercise, calories eaten, and family income level.

However, when the researchers looked at individual food groups instead of the overall score, they found two important patterns. Students who ate more fruit had better sleep quality—the more fruit they ate, the better they tended to sleep. This makes sense because fruit contains nutrients and compounds that might help the body relax and prepare for sleep.

The second finding was unexpected: students who ate more polyunsaturated fats (PUFAs)—which are healthy fats found in foods like fish, walnuts, and vegetable oils—actually reported worse sleep quality. This was surprising because these fats are generally considered very healthy for the heart and brain. The reason for this connection isn’t clear and needs more research to understand.

The study didn’t report other major secondary findings in the abstract, but the fact that individual food components mattered while overall diet quality didn’t is itself an important secondary finding. This suggests that when it comes to sleep, specific foods might be more important than following a general ‘healthy diet’ pattern.

Previous research has suggested that diet affects sleep quality, and some studies have found that certain nutrients and foods help people sleep better. This study adds nuance to that picture by showing that the relationship is more complicated than just ’eat healthy, sleep better.’ The finding about fruit improving sleep aligns with previous research suggesting that fruits contain compounds that support sleep. However, the finding about PUFAs worsening sleep contradicts the general understanding that these fats are beneficial for health, suggesting that their effect on sleep specifically might be different from their other health effects.

This study has several important limitations. First, it only included female college students, so the results might not apply to men or to people of different ages. Second, it was a cross-sectional study, meaning researchers only looked at one point in time, so they couldn’t determine whether diet actually causes better sleep or if people who sleep well just happen to eat more fruit. Third, the study relied on students reporting what they ate and how they slept, which can be inaccurate. Fourth, the sample size wasn’t specified in the abstract, making it hard to judge how reliable the results are. Finally, the unexpected finding about PUFAs and sleep needs more research to understand why it happened.

The Bottom Line

Based on this study alone, a moderate recommendation would be to consider eating more fruit if you’re having trouble sleeping, as this showed a clear connection to better sleep. However, don’t make major dietary changes based on this single study. If you’re struggling with sleep, talk to a doctor or registered dietitian who can give you personalized advice. The finding about PUFAs is too unexpected and unclear to make any recommendations about limiting these healthy fats—more research is needed first.

This research is most relevant to female college students who are struggling with sleep and wondering if their diet might be the cause. It’s also interesting for nutritionists and sleep specialists who work with young adults. However, the results shouldn’t be applied to men or older adults without more research. People with diagnosed sleep disorders should work with a sleep specialist rather than relying on diet changes alone.

If you increase your fruit intake, you might notice improvements in sleep quality within a few weeks to a couple of months, though this varies from person to person. Sleep quality can be affected by many factors (stress, exercise, screen time, sleep schedule), so diet changes alone might not solve sleep problems. Be patient and consistent with any dietary changes for at least 4-8 weeks before deciding whether they’re helping.

Want to Apply This Research?

  • Track daily fruit servings (aim for 2-3 servings per day) alongside a simple sleep quality rating (1-10 scale each morning) for 8 weeks to see if there’s a personal connection between fruit intake and your sleep
  • Set a specific goal like ’eat one serving of fruit with breakfast and one as an afternoon snack’ and log it in the app daily. Use app reminders to prompt fruit consumption at consistent times, then rate your sleep quality each morning to identify patterns
  • Create a simple weekly report showing average fruit intake versus average sleep quality rating. Look for trends over 4-week periods rather than day-to-day changes, since sleep quality naturally varies. Share patterns with a healthcare provider if making dietary changes for sleep concerns

This research is observational and cannot prove that diet causes changes in sleep quality. Individual results vary significantly based on many factors including stress, exercise, sleep schedule, and underlying health conditions. Before making significant dietary changes to improve sleep, especially if you have a diagnosed sleep disorder, consult with a healthcare provider or registered dietitian. This information is not a substitute for professional medical advice. The study only included female college students, so results may not apply to other populations.