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Why is type 2 diabetes mellitus strongly linked to obesity?

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An anatomical illustration of the human pancreas shows its location near the stomach and intestines, a detailed cross-section highlighting ducts and the islet of Langerhans, and an inset of pancreatic tissue histology with labeled alpha, beta, and delta cells. — diabetes mellitus The islets of Langerhans are responsible for the endocrine function of the pancreas. Each islet contains beta, alpha, delta, and pancreatic polypeptide (PP) cells that are responsible for the secretion of pancreatic hormones. Beta cells secrete insulin, a well-characterized hormone that plays an important role in regulating glucose metabolism.

Type 2 diabetes mellitus is strongly linked to obesity primarily because of the development of insulin resistance. In individuals who are obese, tissues become less sensitive to insulin, rendering them unable to effectively store [glucose].123

While the body may initially compensate for this resistance by producing higher-than-normal levels of insulin, some obese individuals are unable to maintain sufficient production to overcome the resistance. This leads to inadequate regulation of blood glucose concentrations, resulting in hyperglycemia.1

Furthermore, adipose tissue acts as an active endocrine organ, secreting various hormones and substances that influence metabolism. Excess fat accumulation is a central factor in metabolic syndrome, a cluster of conditions—including insulin resistance, high blood pressure, and abnormal cholesterol levels—that significantly increases the risk of developing type 2 diabetes. Ultimately, the interplay between obesity, insulin resistance, and insulin deficiency creates the physiological environment that characterizes the disorder.45312