Polyphagia or hyperphagia is an abnormally strong, incessant sensation of hunger or desire to eat often leading to overeating. In contrast to an increase in appetite following exercise, polyphagia does not subside after eating and often leads to rapid intake of excessive quantities of food. Polyphagia is not a disorder by itself; rather, it is a symptom indicating an underlying medical condition. It is frequently a result of abnormal blood glucose levels (both hyperglycemia and hypoglycemia), and, along with polydipsia and polyuria, it is one of the "3 Ps" commonly associated with uncontrolled diabetes mellitus.

Studies have shown that cannabinoids, such as the endocannabinoids, Anandamide (AEA: C₂₂H₃₇NO₂; 20:4, ω-6), 2-Arachidonilglycerol (2-AG: C₂₃H₃₈O₄; 20:4, ω-6), and the phytocannabinoid, Tetrahydrocannabinol (THC: C₂₁H₃₀O₂), and sucralose, a noncaloric sweetener present in many food products of daily intake, can provoke hyperphagia, as they enhance the preference for and intake of sweet and high-fat food, by a change in sweet taste perception and therefore the activity of neural nuclei involved in taste and reward.