Italian clinical practice GRADE-based guidelines on the diagnosis and treatment of overweight and obesity, endorsed by the Italian National Institute of Health

Abstract Obesity is a chronic relapsing disease associated with increased morbidity and mortality and reduced quality of life. The present GRADE-based guidelines have been commissioned by the Italian Society of Obesity (SIO) by the Italian National Health Institute to provide evidence-based recommendations on obesity diagnosis and treatment. The panel identified 13 clinical questions, organised into four domains: A. diagnostic criteria (4 questions); B. medical nutrition therapy (4 questions); C. pharmacological, surgical, and endoscopic treatments (4 questions); and D. miscellaneous (1 question). The expert panel recommends adopting at least one anthropometric index of abdominal visceral fat distribution beyond body mass index (BMI) for better clinical risk stratification. A structured lifestyle intervention (i.e., medical–nutritional treatment—MNT), preferably based on cognitive–behavioural therapeutic approach and including physical activity and a balanced diet, should be offered to all subjects living with obesity. Pharmacological or surgical treatment should be offered in addition to MNT when MNT is unable to reach clinical goals. In particular, pharmacological treatment should be considered as the preferred option for subjects with BMI > 27 kg/m 2 with comorbidities, and for those with BMI 30–39.9 kg/m 2 , based on individual therapeutic goals and needs, adopting surgical treatment in selected cases or in case of OMM failure to reach clinical goals. For subjects with a BMI > 40 kg/m 2 , surgical treatment may be considered conversely as a preferable option. Reduction of at least 10% of the initial body weight is associated with a better quality of life and a reduced risk of incident depression. The current guideline is endorsed by the Italian National Institute of Health, providing the new, updated clinical and legal reference for professionals involved in the management of subjects living with obesity in Italy.