Healthy plant-based diets improve sleep quality, while unhealthy plant-based diets worsen it in adults
In a cross-sectional study of 5260 adults, higher adherence to healthy plant-based diets (hPDI) and pro-vegetarian diets (PVDI) was associated with lower PSQI scores and a 12% reduction in odds of poor sleep quality. Conversely, higher overall plant-based diet (oPDI) and unhealthy plant-based diet (uPDI) scores were linked to higher PSQI scores and increased odds of poor sleep. Mediation analyses indicated that the beneficial effects were partly mediated by lower BMI, while the harmful effects were mediated by greater depression and less physical exercise.
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Healthy plant-based diets improve sleep quality, while unhealthy plant-based diets worsen it in adults The current body of evidence comprises 1 study. EvidenceHub rates the overall confidence at 34/100 (low).
The Claim
Healthy plant-based diets improve sleep quality, while unhealthy plant-based diets worsen it in adults
This conclusion is most relevant to: Adults aged 18-65 years (N=5260).
What the Research Shows
The conclusion draws on 1 linked study. Highlights from the cited literature:
- ▸Plant-Based Diet and Sleep Quality in Adults: Exploring the Role of Lifestyle and Health Mediators. (Nutrition bulletin, 2026) — In a cross-sectional study of 5260 adults, higher adherence to healthy plant-based diets (hPDI) and pro-vegetarian diets (PVDI) was associated with lower PSQI scores and a 12% reduction in odds of poor sleep quality. Conversely, higher overall plant-based diet (oPDI) and unhealthy plant-based diet (uPDI) scores were linked to higher PSQI scores and increased odds of poor sleep. Mediation analyses indicated that the beneficial effects were partly mediated by lower BMI, while the harmful effects were mediated by greater depression and less physical exercise.
How It Works
The proposed biological pathway:
- ▸Higher hPDI/PVDI associated with lower BMI
- ▸Lower BMI mediates improvement in sleep quality
- ▸Higher oPDI/uPDI associated with greater depression and less physical exercise
- ▸These factors mediate worsening of sleep quality
Who Might Benefit
Evidence fit by population:
- ▸Adults aged 18-65 years (N=5260)
Recommended Dose
N/A
Limitations & Caveats
Important context when interpreting this evidence:
- ▸Cross-sectional design cannot establish causality
- ▸Dietary intake and sleep quality were self-reported, potentially introducing recall bias
- ▸Mediation analyses are exploratory and may not fully account for residual confounding
Frequently Asked Questions
What is the difference between healthy and unhealthy plant-based diets?▼
Healthy plant-based diets emphasize whole grains, fruits, vegetables, nuts, and legumes, while unhealthy plant-based diets include refined grains, sugary beverages, and processed plant foods.
How much did healthy plant-based diets reduce the odds of poor sleep?▼
Higher hPDI and PVDI scores were associated with a 12% reduction in the odds of poor sleep quality.
Why did overall plant-based diet worsen sleep in this study?▼
The overall plant-based diet index included both healthy and unhealthy plant foods, and the harmful effect was partly mediated by greater depression and less physical exercise, suggesting that the quality of plant foods matters.
Can changing to a healthy plant-based diet improve sleep?▼
This observational study suggests an association, but causality cannot be confirmed. Randomized controlled trials are needed to establish whether adopting a healthy plant-based diet improves sleep.
References
- 1.de Oliveira Lima M, de Melo JS, Soares LL, de Menezes RCE, Serenini R, Longo-Silva G. “Plant-Based Diet and Sleep Quality in Adults: Exploring the Role of Lifestyle and Health Mediators..” Nutrition bulletin, 2026. PMID: 42663175 DOI: 10.1111/nbu.70069