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According to the WHO, diabetes mellitus is defined as “a metabolic disorder of multiple etiology, characterized by chronic hyperglycemia (high blood sugar) with disturbances of carbohydrate, fat, and protein metabolism resulting from defects in insulin secretion, insulin action, or both.” Diabetes mellitus is classified into type 1 (T1DM; insulin‐dependent) and type 2 diabetes mellitus (T2DM; non‐insulin‐dependent or adult‐onset). While the main feature of T1DM is the defective production of insulin (by the pancreas) and the requirement of daily administration of insulin, T2DM is characterized by inefficient use of insulin from the body.

T1DM cannot be prevented, and we still do not fully understand what causes the disease. Furthermore, it is still under investigation whether environmental factors could trigger the destruction of the body's insulin‐producing cells. On the other hand, T2DM development and progression are affected by genetic and environmental factors; exposure to an obesogenic environment, characterized by sedentary behavior, increased stress, and excessive energy consumption, is known to exert an effect on preexisting genetic factors.

The prevalence of T2DM has dramatically increased since the 1980s, affecting more than 430 million people, compared to 108 million about three decades ago. The increase in diabetes cases is more evident in low‐ to middle‐income countries. According to the World Health Organization, more than 1.5 million people worldwide died due to diabetes in 2019. The Centers for Disease Control and Prevention (CDC) estimated that almost 80.000 deaths occur each year due to diabetes in the United States. The WHO projects that by 2030, diabetes mellitus will be the seventh most important cause of mortality.

Diabetes mellitus can progressively lead to a host of other metabolic abnormalities affecting the heart, blood vessels, eyes, kidneys, and nerves. It has been shown that individuals suffering from diabetes mellitus have two to three times higher risk for developing CVDs compared to their nondiabetic counterparts. Furthermore, reduced blood flow and nerve damage (i.e., neuropathy) in the lower extremities can substantially exaggerate the occurrence of foot ulcers and infection, even leading to amputation of the lower limbs. Chronic impairments in the small blood vessels of the retina (i.e., retinopathy) can gradually lead to blindness; approximately 3% of all blindness cases worldwide could be attributed to diabetes. Finally, diabetes mellitus constitutes one of the major causes of renal failure.