The Impact of Sleep Deprivation on Hunger-Related Hormones: A Meta-Analysis and Systematic Review

Introduction: Short sleep duration has been implicated in an increased body mass index (BMI), potentially through disruptions in appetite-regulating hormones, such as leptin and ghrelin. Methods: This systematic review and meta-analysis aimed to examine the effects of sleep deprivation on circulating levels of these hunger hormones and their possible role in obesity. Six randomized controlled trials (RCTs) involving 141 participants were included in the analysis, with sleep deprivation typically manipulated through restricting sleep by 4–5 h or keeping participants awake for 24 h. Data on leptin and ghrelin levels were extracted from blood samples, and statistical analysis was conducted using a random-effects model. Results: The results revealed no significant changes in ghrelin (SMD: −0.27, 95% CI: −1.00, 0.46, p = 0.4712) or leptin (SMD: 0.10, 95% CI: −0.22, 0.42, p = 0.5266) levels following sleep deprivation, contrary to prior studies suggesting a link between sleep loss and altered appetite regulation. Significant heterogeneity was observed for ghrelin levels (I2 = 83.83%, p < 0.001), but not for leptin (I2 = 21.86%, p = 0.4049). Variations in study design, including differences in blood sampling timing and participant BMI, may explain this variability. Conclusions: These findings suggest that, at least in the short term, sleep deprivation does not consistently affect leptin and ghrelin levels. Given the complex relationship between sleep and appetite regulation, future research should focus on standardized study designs, participant characteristics, and more precise measurements to further explore these mechanisms.