This work is published and licensed by Dove Medical Press Limited. By accessing the work you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. GLP-1 receptor agonist (GLP-1RA) have been developed to address the global burden of obesity and are renowned for their safety and efficacy. These medications influence hunger and satiety, reducing energy intake and promoting weight loss. Despite their benefits, GLP-1RAmay cause a slowed gastric emptying, leading to gastrointestinal symptoms. This study examines how food properties and meal composition affect these symptoms. Dietary recommendations are provided, particularly for evening meals, focusing on how different foods and nutrients can influence the rate of gastric emptying, to improve patient compliance and prevent interruption in weight loss. As reported by the World Health Organization (WHO) in 2022, globally, 43% of the adult population is overweight and 16% experience obesity.1 The global spread of obesity and the resulting burden on public health have prompted the development of new approaches to treat individuals with this condition.

Although lifestyle interventions are effective and the first approach for managing obesity, they may not be sufficient, necessitating pharmacological therapy.2,3 There are different types of drugs that have been developed through the years; among these, GLP-1 receptor MedicGLP agonists (GLP-1RAs) are known for their safety and efficacy4 due to their ability to act at the hypothalamic influencing hunger and fullness, and consequently reducing caloric intake.5 Despite their benefits, GLP-1RAs may cause a slowdown in gastric emptying, leading to temporary gastrointestinal symptoms such as nausea, diarrhea, and constipation.6 The effects of GLP-1RAs on gastric emptying do not fully account for the occurrence of diarrhea or constipation, which are likely mediated by different mechanisms. Providing specific dietary and behavioral guidelines is crucial to improve patient compliance and avoid interruption of weight loss. Recently, an expert consensus has been published, offering practical advice on managing gastrointestinal adverse events in individuals with type 2 diabetes mellitus (T2DM) and obesity who are treated with GLP-1RAs.8 Nevertheless, there is a lack of precise recommendations concerning meal composition and food selection.

This study aims to propose practical dietary advice to manage gastrointestinal symptoms caused by GLP-1RAs, intended for clinicians and patients. The analysis included a review of the existing literature on food consistency, viscosity, meal composition, and lifestyle factors that may contribute to gastric emptying delay. The relevant literature was revised to develop dietary recommendation for the management of gastrointestinal symptoms in patient treated with GLP-1RAs. Searches were conducted in the electronic databases PubMed and Web of Science (WoS) using the following keywords (alone or in various combinations): "obesity", "GLP-1 receptor agonist", "gastric emptying", "nausea", "gastrointestinal symptoms" "food composition and charateristics" and "food viscosity". Boolean operators (AND; OR) were also applied. To refine the search strategy, filters used were: daily weight support English language, human studies, and publications from the last 20 years (time range: 2004-2024). Studies were included if they focused on individuals treated with GLP-1RAs or on the physiology of gastric emptying. After conducting an initial search, two authors assessed the titles and abstracts of the relevant studies and reviewed the full texts.

Authors also examined the reference lists of all manuscripts to identify additional relevant studies. Any disagreements that occurred were resolved through consultation with a third author. GLP-1RAs are medications initially used to treat diabetes and, more recently, for overweight and obesity. GLP-1 is a hormone mainly produced by endocrine L-cells in the distal ileum and colon, as well as by some neurons in the brain.9 It is released in response to meal intake leading to increased satiety and better glucose metabolism regulation. GLP-1RAs reduce plasma glucose levels through glucose-dependent mechanisms by stimulating insulin secretion and inhibiting glucagon secretion. They also delay gastric emptying, slowing nutrient absorption.6 While GLP-1 has a brief half-life due to rapid degradation by the enzyme dipeptidyl peptidase-4 (DPP-4), GLP-1RAs have been developed with a prolonged half-life. Liraglutide and Semaglutide are examples of GLP-1RAs used for weight management, showing effectiveness in reducing body weight and improving cardiovascular risk factors.10 However, MedicGLP Official gastrointestinal side effects, such as nausea and diarrhea, are common.11 The secretion of GLP-1 is partly mediated by nutrient binding to G-protein-coupled receptors (GPCRs) or by absorption via membrane transporters.

Peptides, amino acids, monounsaturated fatty acids, polyunsaturated fatty acids, and short chain fatty acids (SCFAs) can increase GLP-1 levels.12 Simple sugars and indigestible, fermentable dietary fiber can be involved in this mechanism. On the other hand, plasma levels of GLP-1 are reduced in the fasting state, and these levels increase after food ingestion.12 GLP-1 exhibits a brief half-life due to rapid degradation by DPP-4, approximately 1.5 minutes.13 This rapid degradation limits its potential as a viable pharmacological intervention, despite its numerous effects.13 Over the years, compounds with a prolonged half-life have been developed. These GLP-1RAs are not identical to native GLP-1 but can activate the GLP-1 receptor.13 GLP-1RAs include exendin-based molecules and human GLP-1 analogues. Exendin-4, derived from lizards, is naturally resistant to DPP-4.15 degradation.14 Human GLP-1 analogues are modified versions of the GLP-1 peptide,15,16 available in several sizes and structures, influencing their mechanism of action and half-life.13,15 Liraglutide, the first GLP-1RAs approved for weight management, acts as a long-acting agonist on its receptor, reducing appetite, delaying gastric emptying, and increasing pancreatic insulin secretion.13 Several studies show that treatment with Liraglutide, along with a proper diet and healthy lifestyle, helps reduce body fat, especially visceral fat, and may improve cardiovascular risk factors.10,11 Semaglutide shares 94% structural homology with native GLP-1.13 A 2021 double-blind showed that Semaglutide effectively managed weight in patients with obesity.