Diet and nutrition in obesity treated with incretin-based therapies: A scientific statement of the Polish Society of Dietetics.

Incretin-based therapies, including glucagon-like peptide-1 receptor agonists (GLP-1 RAs) and dual GIP/GLP-1 receptor agonists, have transformed obesity treatment by producing substantial weight loss and improving cardiometabolic outcomes. However, their therapeutic effects are accompanied by nutritional challenges, including reduced energy intake, gastrointestinal adverse effects, loss of lean mass or fat-free mass, and the risk of inadequate protein and micronutrient intake. This scientific statement of the Polish Society of Dietetics (PTD) summarizes current evidence and provides clinical guidance on nutritional care during incretin-based therapy for obesity. The statements were developed through multidisciplinary expert synthesis and consensus; direct nutrition-specific evidence remains limited, and no formal evidence-grading system was applied. The main features of evidence-informed nutritional care during incretin-based therapy include: 1) structured baseline nutritional assessment and ongoing monitoring of dietary intake, appetite, gastrointestinal tolerance, and body composition; 2) early identification of nutritional risk, including inadequate protein intake, micronutrient insufficiency, dehydration, and excessive loss of lean mass or fat-free mass; 3) individualized dietary strategies supporting adequate nutrient intake and treatment tolerance; 4) preservation of lean mass and muscle function through appropriate protein intake and regular resistance exercise; 5) use of Mediterranean, Dietary Approaches to Stop Hypertension (DASH), or appropriately planned plant-based dietary patterns adapted to individual clinical needs; 6) targeted rather than routine nutritional supplementation based on documented deficiency or increased clinical risk; and 7) integration of registered dietitians within multidisciplinary obesity care pathways. Future research should evaluate the effects of structured dietitian-led interventions on body composition, nutritional status, treatment adherence, and long-term clinical outcomes during incretin-based therapy.