Ketosis is a metabolic state in which most body cells utilize ketone bodies and molecules of fatty acid instead of glucose to produce ATP instead. Human beings, and mammals, are in this metabolic state when they are fasting, or when they eat
exclusively fat and meat instead of carbohydrates-rich food. During dietary ketosis, the amount of ketone bodies in the bloodstream ranges from 1 to 4 millimolars per liter. During starvation, however, it ranges between 4 to 8 millimolars. More than that, it is called ketoacidosis, which happens in type I diabetic patients.
Although ketoacidosis is dangerous, ketosis is good for your health, because it promotes mitochondrial neogenesis, which is the production of more mitonchondria per cell through division. The more mitochondria per cell, the faster the ATP generation per second will be. The reason for the production of more mitochondria within the cells is the fact that ketone bodies does not leave free radicals, such as hydroxyl, as glucose does during glycolysis. Free radicals damage either the nuclear or the mitochondria's membrane.
Ketone bodies are produced through two metabolic processes, one called lipolysis, and the other ketogenesis. The first one is the breaking down of triglyceride (body fat) and dietary fat into one glycerol and three fatty acids through the intervention of the glucagon (pancreatic hormone). Ketogenesis is the synthesis of ketone bodies from fatty acid by the liver cell mitochondria (beta-oxidation); there are three ones: beta-hydroxybutyrate, acetoacetate, and acetone. Once synthesized, they are carried in the arterial bloodstream to every tissue, where they are converted into acetyl-CoA in the cell cytoplams before entering the citric acid cycle.
