A group of nonenzymatic reactions in which ALDEHYDES; KETONES; or reducing sugars react with the amino groups of AMINO ACIDS; PEPTIDES; PROTEINS; LIPIDS; or NUCLEIC ACIDS.The reaction with reducing sugars (glycation) results in formation of Schiff bases which undergo Amadori rearrangement and other reactions that result in the irreversible formation of ADVANCED GLYCATION END PRODUCTS (AGEs). Food browning, such as occurs when cooking with high heat (grilling, frying, roasting, etc.) is attributed to the Maillard reaction. Non-enzymatic glycation and subsequent formation of AGEs also occurs in vivo and is accelerated under hyperglycemic and inflammatory conditions, and OXIDATIVE STRESS.