Hyperinsulinaemia as a cause of obesity and cardiometabolic diseases

This narrative Review explores the role of hyperinsulinaemia as a potential independent contributor to obesity and cardiometabolic diseases. We argue that scientific discussions about the role of hyperinsulinaemia as a causal factor in these conditions have not sufficiently distinguished between postprandial insulin excursions and chronically elevated basal levels of insulin. We summarize findings from observational and experimental human trials, as well as preclinical models, and outline how reasonable evidence suggests that chronic (basal) exposure to elevated levels of insulin, rather than normal postprandial insulin excursions in isolation, might have a role in promoting or exacerbating the development of adiposity. We discuss the putative contributors to hyperinsulinaemia, including genetic predisposition, early-life influences, diet, environmental pollutants and physical inactivity, highlighting causality knowledge gaps relevant to the prevention of obesity and cardiometabolic diseases.