PHASE I: In the correlation study a clinical, biochemical and instrumental evaluation will be performed in 20-30 patients with very severe obesity (grade III) with GHD followed-up in a multi-disciplinary approach at the Unit of Endocrinology of the Departments of Molecular and Clinical Endocrinology and Oncology and at the Physiology Nutrition Unit of the Department of Neuroscience and the Department of Surgery of "S. Giovanni Bosco" Hospital of Naples, according to the current criteria of the National Institute of Health (27). The clinical examination will focus on the GH/IGF-I status effects on body composition changes before and after LASGB. The clinical examination will determine anthropometric indexes (weight, height, BMI, waist circumference). The biochemical evaluation will include the measurement of lipid profile, fasting plasma glucose and insulin, liver test function, FT3, FT4, GHRH + Arginine test to detect GHD, plasma IGF-I levels. The instrumental evaluation will include DEXA Total Body and bioimpedance analysis to determine body composition, and liver ultrasounds.