Associations of Dietary Patterns and Physical Activity with Sleep Quality and Metabolic Health Markers in Patients with Obstructive Sleep Apnea: An Exploratory Pilot Study

<b>Background/Objectives:</b> Obstructive sleep apnea (OSA) is often accompanied by metabolic syndrome (MetS), forming a high-risk phenotype with elevated cardiometabolic burden. The contribution of lifestyle behaviors-particularly eating mechanics and psychological eating cues-to disease severity remains unclear. This study examined independent associations of dietary behaviors and physical activity (PA) with OSA severity, sleep quality, and metabolic health. <b>Methods:</b> Forty-four OSA patients (mean age 38.3 ± 9.1 years; 89% male) underwent attended polysomnography, dual-energy X-ray absorptiometry, and metabolic profiling. Validated questionnaires assessed dietary behaviors, PA, and sleep quality. Hierarchical logistic regression identified predictors of MetS, severe OSA, and poor sleep quality. <b>Results:</b> The prevalence of MetS was 45%. Compared with those with OSA alone, participants with MetS demonstrated significantly greater central adiposity and more severe nocturnal hypoxemia, despite similar apnea-hypopnea indexes. In multivariable models, MetS was independently associated with higher body mass index (adjusted odds ratio [aOR] = 1.64; <i>p</i> = 0.008) and reward eating (aOR = 3.34; <i>p</i> = 0.041), whereas higher total PA was associated with reduced odds (aOR = 0.96; <i>p</i> = 0.026). Poor subjective sleep quality was significantly associated with younger age (aOR = 0.91; <i>p</i> = 0.037). For severe OSA, slow chewing was associated with significantly reduced odds (aOR = 0.24; <i>p</i> = 0.038), while emotional eating was associated with increased odds (aOR = 2.40; <i>p</i> = 0.048). <b>Conclusions:</b> This hypothesis-generating study identifies a high-risk OSA phenotype marked by metabolic dysfunction and hypoxemia. Eating speed (a proxy for mindful eating), emotional and reward-driven eating, and PA independently shape metabolic and respiratory outcomes. These findings support incorporating behavioral nutrition into multidisciplinary OSA management.