Gluconeogenesis is the process by which glucose is synthesized in the liver from non-carbohydrate carbon substrates like lactate, glycerol, and glucogenic amino acids. This process is crucial for meeting the body's basal glucose requirements, especially during periods of fasting when glucose stores have been depleted, as glucose is essential for energy in tissues like the brain, red blood cells, and skeletal muscles. Gluconeogenesis also helps clear excess metabolites from the blood that can accumulate from tissue breakdown.