Obstructive sleep apnea–hypopnea syndrome (OSAHS) is a common respiratory disorder frequently associated with obesity and increased cardiometabolic morbidity.While continuous positive airway pressure (CPAP) is the standard treatment, nutritional assessment and management are still insufficiently integrated into routine clinical practice.To evaluate the nutritional status of obese patients with OSAHS and compare their clinical and polygraphic characteristics across two obesity levels.We conducted a cross-sectional, descriptive, and analytical study in April 2024 at the Pulmonology and Endocrinology Departments of Hedi Chaker University Hospital, Sfax, including 40 adults with overweight or obesity (BMI ≥25 kg/m²) and confirmed OSAHS, who underwent a full dietary evaluation. Patients were grouped by BMI ( group 1:<40kg/m²;  group 2: ≥40 kg/m²). Clinical, polygraphic, anthropometric, bioimpedance, and dietary data were collected. Statistical analysis used SPSS 25, with p <0.05 considered significant.The population was predominantly female (75%) with a median age of 56 years. Cardiometabolic comorbidities were frequent: hypertension (57.5%), diabetes (32.5%), and dyslipidemia (32.5%). All patients reported typical  OSAHS symptoms. The median AHI was 22.55, and the median BMI was 37.7 kg/m², with 37.5% having morbid obesity. Mean daily energy intake was 2177.5 kcal, with 55.5% carbohydrates, 33.4% lipids, and 11% proteins; median fiber intake was 14.5 g/day, while calcium (402.4 mg/day) and iron (7.065 mg/day) intakes were below the recommended levels. Group 2 reported more insomnia (66.7% vs 32%, p = 0.033) and exertional dyspnea (86.7% vs 52%, p = 0.027), while polygraphic parameters showed no significant differences.In our study, OSAHS  predominantly affected women ,with low exposure to tobacco and alcohol, reflecting Tunisia's sociocultural context. Nutritional assessment revealed severe obesity  with excessive lipid and simple carbohydrate intake, and insufficient fiber and micronutrient consumption, dietary patterns that may contribute to OSAHS onset or progression. Morbid obesity was associated with higher rates of dyspnea and insomnia, but was not linked to increased AHI severity, consistent with previously reported inconsistencies in the relationship between BMI and polygraphic severity.Obese Tunisian patients with OSAHS showed poor dietary quality and morbid obesity was associated with greater dyspnea and insomnia, highlighting the need for  systematic  screening and structured nutritional management.