Behavioral–Gastrointestinal Interaction Between Night Eating Syndrome and GERD Among Saudi Adults: Implications for Clinical Screening and Lifestyle-Based Care

<b>Background and Objectives</b>: Gastroesophageal reflux disease (GERD) is a prevalent gastrointestinal disorder that significantly affects quality of life. Night eating syndrome (NES), characterized by evening hyperphagia and nocturnal eating, may worsen reflux through delayed gastric emptying and increased nocturnal acid exposure, yet evidence in young adults remains limited. This study aimed to estimate the prevalence of GERD and NES, examine their association, and identify clinically relevant predictors among adults in southern Saudi Arabia. <b>Methods</b>: A cross-sectional study was conducted among 831 adults (≥18 years) in the Jazan region between November 2024 and April 2025. Data were collected using a validated 54-item online questionnaire assessing sociodemographic characteristics, lifestyle behaviors, dietary habits, and medical history. GERD was defined using the GerdQ (score ≥ 8), and NES using the night eating questionnaire (NEQ ≥ 25). Multivariable logistic and linear regression analyses were performed to identify independent predictors. <b>Results</b>: The prevalence of GERD was 25.6%, and 9.7% of participants met the criteria for NES. Higher NEQ scores were independently associated with increased odds of GERD (OR = 1.05, 95% CI: 1.02-1.07; <i>p</i> = 0.001). GERD was predicted by tea consumption, middle income (10,000-14,999 SAR), asthma, hiatal hernia, and a family history of GERD. NES was independently associated with GERD, smoking, and frequent intake of fatty foods, chocolate, salty foods, and soft drinks, while male sex, employment or student status, higher income, and fiber-rich food intake were protective. <b>Conclusions</b>: NES is significantly associated with GERD among young adults. Integrating screening for disordered eating behaviors and dietary counseling into routine GERD care may improve clinical outcomes.