Ultra-Processed Food Consumption and Mental Health and Sleep Quality in Turkish Adults: A Cross-Sectional Study

Background/Objectives: Ultra-processed foods are thought to affect sleep and mental health. The aim of this study was to examine the relationships between ultra-processed food consumption and mental health (mental well-being, depression, anxiety, and stress) and sleep quality in Turkish adults. Methods: In this cross-sectional study (n = 2935), the status of adult individuals was determined via the Short Screening Questionnaire of Highly Processed Food Consumption (sQ-HPF), the Warwick-Edinburgh Mental Well-being Scale (WEMWBS), the Depression-Anxiety-Stress Scale 21 (DASS-21), the Beck Depression Inventory (BDI), and the Pittsburgh Sleep Quality Index (PSQI). Pearson correlation and multivariate path analysis were used to examine the relationships between the scales. Results: Forty-six percent of the participants had a minimal level of depression, and the vast majority of participants had poor sleep quality (84%). According to the sQ-HPF classification, individuals exhibiting high consumption had higher DASS-21, BDI, and PSQI scores but lower WEMWBS scores than individuals exhibiting low consumption (p < 0.001). The sQ-HPF was found to have independent and significant associations with mental well-being, depression, mood symptoms, and sleep quality. A 1-unit increase in the total sQ-HPF score led to a 0.26-unit decrease in the WEMWBS score (β = −0.05; p = 0.004). In the model established for depression (BDI), a 1-unit increase in sQ-HPF corresponded to a 0.32-unit increase in the BDI score (β = 0.09; p < 0.001). Similarly, sQ-HPF was found to be a positive and significant predictor of the total DASS-21 score (β = 0.11; p < 0.001). The sQ-HPF total score showed the strongest positive correlation with impaired sleep quality, with a 1-unit increase in sQ-HPF leading to a 0.13-unit increase in the PSQI score (β = 0.15; p < 0.001). Conclusions: The consumption of ultra-processed foods is associated with poorer mental health and sleep quality, regardless of age, sex, and socioeconomic factors.