When most people eat less than around 50 grams a day of carbohydrate, they soon start producing high levels of something called "ketone bodies". These are simply breakdown products of fat, and are used to fuel cells that normally depend on glucose. Clinical trials in adults have used the terms “keto-induction” and “keto-adaptation” to describe the time periods of interest in the development and resolution of side effects of KD. Keto-induction refers to immediate effects within several days whereas keto-adaptation is used to refer to multiple organ homeostasis to using ketones as the primary source of energy . However, the terms have been used somewhat interchangeably.