GLP-1-Based Therapies for Obesity: Efficacy, Safety and Nutritional Implications of a Changing Treatment Landscape

This narrative review examines the efficacy, safety, and nutritional implications of glucagon-like peptide-1 (GLP-1)-based therapies for obesity management, including semaglutide, liraglutide, and tirzepatide. Drawing on clinical trials, observational studies, review articles, and guidance from major health organizations, it explores their mechanisms of action, weight-loss outcomes, adverse effects, and the potential for weight regain following treatment discontinuation. Particular attention is given to the nutritional implications of appetite suppression, including protein adequacy, preservation of lean mass, micronutrient intake, dietary variety, fibre, hydration, and gastrointestinal tolerance. The review also discusses the integration of pharmacotherapy with nutrition care, physical activity, behavioural support, and long-term clinical monitoring. Finally, it highlights outstanding research questions concerning long-term outcomes, affordability, and equitable access to treatment. This work aims to contribute to evidence-informed discussion of GLP-1-based therapies from clinical nutrition and public health perspectives.