In a groundbreaking new study published in the open-access journal PLOS One, researchers have unveiled compelling evidence that sleep quality, dietary habits, and physical activity play pivotal roles in shaping the psychological wellbeing of young adults. This research, led by Dr. Jack Cooper and colleagues from the University of Otago in New Zealand, provides fresh insights into how these three lifestyle factors independently and interactively contribute to mental health outcomes during a critical developmental stage of life.
The study uniquely emphasizes the profound impact of sleep on mental wellbeing. Utilizing data drawn from multiple large-scale samples spanning New Zealand, the United Kingdom, and the United States, the investigation reveals that among the three behaviors examined, sleep quality emerges as the most consistent and influential predictor of next-day psychological wellbeing. Participants reporting better sleep demonstrated significantly enhanced mood and mental health markers, underscoring sleep’s foundational role in emotional regulation and cognitive resilience.
Beyond sleep, dietary intake—specifically the consumption of fruits and vegetables—was also strongly correlated with improved mental health metrics. Notably, the research highlights that eating higher quantities of these nutrient-dense foods not only supports wellbeing but may also buffer against the negative psychological effects of poor sleep. This bidirectional relationship suggests that diet and sleep quality may operate synergistically to support mental health, a finding that challenges existing paradigms that often consider these factors in isolation.
Physical activity, monitored through both subjective daily diaries and objective Fitbit data, also demonstrated beneficial associations with wellbeing, though these effects were more prominent when examined within individuals over time rather than between different individuals. This nuance points to the complex dynamics of how exercise influences mood: the mental health benefits of being active might fluctuate more significantly on a day-to-day basis within a person rather than serve as a distinguishing characteristic across a broader population.
The research leverages a robust methodological approach by integrating three separate studies encompassing varied data collection techniques. A cross-sectional survey of over a thousand participants captured broad patterns across countries, while two more granular daily diary studies—one complemented by wearable technology—offered temporal insights into how daily variations in behaviors predict psychological states. This mixed-method approach strengthens the validity of the findings and provides a multifaceted perspective on young adults’ wellbeing.
Crucially, the research delineates that the beneficial effects of sleep, diet, and physical activity are mostly independent yet additive. This means the more one engages in these positive health behaviors, the greater the cumulative boost to psychological wellbeing. The study’s statistical modeling illuminates that these lifestyle factors do not merely coexist but interact dynamically, potentially amplifying their collective impact on mental health outcomes.
One of the study’s most surprising revelations is how increased fruit and vegetable intake appeared to moderate the adverse impact of poor sleep on wellbeing, suggesting a protective nutritional effect. Conversely, a good night’s sleep similarly seemed to protect against the consequences of lower fruit and vegetable consumption. This interplay hints at the possibility of compensatory mechanisms within lifestyle factors—where deficits in one area might be partially mitigated by strengths in another.
The age group examined—17 to 25 years old—is particularly noteworthy given the unique developmental challenges faced by young adults. Transitioning from adolescence to full adulthood often involves navigating a complex web of stressors, including educational pressures, financial concerns, social changes, and identity formation. By pinpointing modifiable lifestyle factors that promote mental flourishing during this tumultuous period, the study offers practical implications for public health initiatives and individual interventions alike.
While the research represents a significant advance, the authors acknowledge certain limitations. Sample populations were relatively homogenous and geographically constrained to Western countries, potentially limiting the generalizability of the findings. Additionally, the observational nature of the study precludes definitive causal inference, necessitating future experimental and longitudinal studies to disentangle the directional pathways linking behavior to psychological outcomes.
The findings nonetheless carry powerful real-world relevance. Dr. Jack Cooper underscores that mental wellbeing need not require radical lifestyle overhauls. Incremental improvements—such as modestly extending sleep duration, increasing fruit and vegetable consumption, or adding just ten extra minutes of physical activity daily—can translate into measurable enhancements in how young adults feel. This democratizes the notion of mental health improvement by framing it as accessible and achievable through manageable lifestyle tweaks.
Professor Tamlin Conner, senior author from the University of Otago Psychology Department, emphasizes the importance of these insights for supporting thriving rather than mere survival during young adulthood. As this life stage encompasses substantial personal and societal transitions, identifying concrete behavioral levers that bolster wellbeing equips practitioners and policymakers with actionable tools to foster healthier, more resilient populations.
Sleep quality’s standout role as a “strongest and most consistent predictor” reflects growing scientific consensus recognizing sleep as a cornerstone of mental and physical health. Complemented by the reinforcing effects of diet and physical activity, this triad forms a holistic lifestyle framework that young people—and indeed individuals across the lifespan—can harness to optimize psychological wellbeing amidst the myriad pressures of modern life.
This research heralds a shift toward integrative approaches in mental health promotion that synthesize behavioral science with nutritional and physiological science. By elucidating the intertwined pathways through which sleep, diet, and exercise influence daily mood states, the study lays a foundation for novel intervention paradigms that are both evidence-based and tailored to the dynamic lifestyles of young adults.
As global mental health challenges continue to escalate—particularly among younger demographics—studies such as this serve as vital beacons guiding the way toward sustainable, scalable, and holistic wellbeing strategies. The nuanced understanding that small, additive lifestyle changes can yield meaningful psychological benefits offers hope and practical direction for individuals, clinicians, educators, and policymakers alike.
In sum, this extensive cross-national investigation illuminates how intimately lifestyle behaviors are intertwined with mental wellbeing. By confirming the primacy of sleep alongside valuable contributions from diet and physical activity, the research advances our comprehension of mental health determinants in young adults and charts a hopeful course toward thriving, not just surviving, in an increasingly complex world.
Subject of Research: Psychological wellbeing in young adults
Article Title: From surviving to thriving: How sleep, physical activity, and diet shape well-being in young adults
News Publication Date: 27-Aug-2025
Web References: http://dx.doi.org/10.1371/journal.pone.0329689
References: Cooper JR, Turner RS, Conner TS (2025) From surviving to thriving: How sleep, physical activity, and diet shape well-being in young adults. PLoS One 20(8): e0329689.
Image Credits: Anthony Lewis, PLOS, CC-BY 4.0
Keywords: sleep quality, psychological wellbeing, young adults, fruit and vegetable intake, physical activity, mental health, lifestyle behaviors, daily diary study, Fitbit, diet, additive effects, mental resilience
