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.
Evidence Score
Study Evidence
Study 1. Plant-Based Diet and Sleep Quality in Adults: Exploring the Role of Lifestyle and Health Mediators.
observationalde Oliveira Lima M, de Melo JS, Soares LL, de Menezes RCE, Serenini R, Longo-Silva G · Nutrition bulletin (2026)
Result:
Mechanism Graph
Limitations
- ⚠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.
Products
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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