Definition for Ketosis
From Biology Forums Dictionary
1) Ketosis is a state of elevated levels of ketone bodies in the body. It is almost always generalized throughout the body, with hyperketonemia, that is, an elevated level of ketone bodies in the blood. Ketone bodies are formed by ketogenesis when liver glycogen stores are depleted. The ketone bodies acetoacetate and β-hydroxybutyrate are used for energy.
2) In general, if you do not eat enough carbohydrate to support regular exercise, your body will have to rely upon fat and protein as alternative energy sources. While most of the body tissues can use fat and protein for energy, the brain prefers to use glucose. Thus, when carbohydrate intake is too low, the body begins to break down stored fat to produce an alternative fuel called ketones.
Ketones can provide energy to the brain during situations of fasting, low carbohydrate intake, or vigorous exercise. However, ketones also suppress appetite and cause dehydration and acetone breath. If inadequate carbohydrate intake continues for an extended period, the body will produce excessive amounts of ketones. Because many ketones are acids, high ketone levels cause the blood to become acidic, leading to a condition called ketoacidosis. The high acidity of the blood interferes with basic body functions, causes the loss of lean body mass, and damages many body tissues.
When our body uses proteins for energy, the amino acids from these proteins cannot be used to make new cells, repair tissue damage, support our immune system, or perform any of their other functions. During periods of starvation or when eating a diet that is very low in carbohydrate, our body will take amino acids from the blood first, and then from other tissues like muscles, heart, liver, and kidneys. Using amino acids in this manner over a prolonged period of time can cause serious, possibly irreversible, damage to the organs.