The key finding
A 2025 meta-analysis examining the relationship between diet quality and sleep found that people with higher Healthy Eating Index (HEI) scores—a standardized measure of how well someone’s diet aligns with dietary guidelines—were associated with better sleep outcomes. Specifically, higher HEI scores were linked to a 14% lower risk of poor sleep quality (odds ratio = 0.860) and a dramatic 70% lower risk of abnormal sleep duration (odds ratio = 0.296). The analysis pooled data from five observational studies to examine whether what we eat correlates with how well we sleep.
What the study looked like
This meta-analysis combined results from five previously published observational studies that examined the relationship between diet quality, measured by the Healthy Eating Index, and sleep outcomes. The researchers searched multiple major scientific databases—PubMed, Cochrane, Medline, Web of Science, and EMBASE—to identify all relevant studies. The HEI is a scoring system that rates diet quality based on how closely eating patterns follow established dietary guidelines, considering factors like fruit and vegetable intake, whole grains, protein sources, and limiting added sugars and saturated fats. The studies included in this analysis looked at two main sleep outcomes: sleep quality (how well people felt they slept) and sleep duration (whether people slept abnormally short or long periods). Because this was a meta-analysis, it didn’t recruit new participants but instead statistically combined existing research to identify overall patterns.
Why researchers think this happened
While the meta-analysis itself focuses on confirming the statistical association rather than explaining mechanisms, the underlying research suggests several pathways through which diet quality might influence sleep. Higher-quality diets typically contain more nutrients that support neurological function and regulate circadian rhythms—the body’s internal clock that controls sleep-wake cycles. Diets rich in fruits, vegetables, whole grains, and lean proteins provide vitamins, minerals, and antioxidants that may reduce inflammation and oxidative stress, both of which have been linked to sleep disturbances. Conversely, diets high in processed foods, added sugars, and saturated fats may disrupt metabolic processes and neurotransmitter production that regulate sleep. The researchers note that this meta-analysis confirms patterns observed in individual epidemiological studies, providing stronger evidence for a relationship between overall dietary patterns and sleep health than any single study could offer.
How to read this carefully
Several important limitations deserve attention. First, all five included studies were observational, meaning they tracked people’s existing diets and sleep patterns rather than randomly assigning diets—so we cannot conclude that improving diet causes better sleep, only that the two are correlated. People with healthier diets might also have other lifestyle factors that promote better sleep, such as regular exercise, lower stress, or better overall health habits. The analysis included only five studies, a relatively small number, which limits how confidently we can generalize these findings. Additionally, both diet quality and sleep were often self-reported in the original studies, which can introduce bias or inaccuracy. The dramatic 70% reduction in abnormal sleep duration had very wide confidence intervals, suggesting substantial uncertainty around that specific estimate. Replication in larger, more diverse populations and ideally in randomized controlled trials would strengthen these findings.
What this means for everyday life
This meta-analysis adds to growing evidence that what we eat may matter for how we sleep. While it doesn’t prove that changing your diet will fix sleep problems, it suggests that diet quality and sleep health are connected in ways worth considering. If you struggle with sleep, examining your overall eating patterns—not just individual foods or nutrients—might be one factor worth exploring alongside other sleep hygiene practices. The HEI emphasizes balance: more fruits, vegetables, whole grains, and lean proteins, and fewer added sugars and heavily processed foods. Given this association, people interested in improving sleep might consider whether their current diet aligns with these general principles. However, sleep disorders have many potential causes, from stress to medical conditions, so dietary changes should be viewed as one potential component of sleep health rather than a standalone solution. Anyone with persistent sleep problems should consult healthcare providers rather than relying solely on dietary adjustments.