Combined Assessment of Gastrointestinal Hormones and Metabolomic Profiling Following Mixed-Meal Tolerance Tests in Patients at Increased Risk of Refeeding Syndrome: Study Protocol - Gonçalo Nunes; Marta Guimarães; Sofia S. Pereira; Ivo Mendes; Francisco Vara-Luiz; Cátia Oliveira; Marta Gonçalves; Patrícia Mendes; Rute Santos; Tânia Meira; Jorge Fonseca (Journal of Personalized Medicine, 2026)