Effect of GLP-1 receptor agonist on nutrient intake: A narrative review

Humans have a primitive defense mechanism called metabolic adaptation that slows voluntary weight loss. It works by downregulating hormones that reduce food intake and by lowering the metabolic rate. Second-generation GLP-1 receptor agonists, such as semaglutide or tirzepatide, promote weight loss by targeting this hormonal system to control appetite. Appetite can be divided into hunger, satiety, satiation, and reward eating. This review will examine how GLP-1 receptor agonists and newer satiety hormone agonists influence appetite and its components. Research indicates that these new satiety hormone agonists significantly reduce meal size and may decrease overall water intake. Additionally, the choice of highly palatable foods is affected and may extend to alcohol consumption. Clinicians need to understand how these new drugs affect food intake to counsel patients effectively. Most patients will experience gastrointestinal side effects, which can often be managed with dietary adjustments. Other clinical issues stemming from the substantial decrease in food intake will also need to be monitored. Loss of lean tissue, including bone and muscle, has been reported. Clinicians can adjust dosing of these medications but will need to make nutritional adjustments to help mitigate these effects. Now that these powerful weight-loss agents have been available for several years, vitamin deficiencies have been reported. Given the side effects of GLP-1 receptor agonists and their intended appetite suppression, clinicians' nutritional counseling and treatment become invaluable.