Wiktionary(1.00 / 1 vote)Rate this definition: quantity(Noun) A fundamental, generic term used when referring to the measurement (count, amount) of a scalar, vector, number of items or to some other way of denominating the value of a collection or group of items. You have to choose between quantity and quality.
When the body is making and using ketones we say that the body is in a state of ketosis. Ketosis begins after about 48 hours (2 days) or water fast for women, or about 72 hours (3 days) of water fast for men.
You can also buy Ketone Test Strips at Netrition.com. How Long Does It Usually Take To Get Into Ketosis? The body can only store a two-day supply of glucose in the form of glycogen, so after two days of consuming no more than 20 grams of carbohydrates, most people go into lipolysis/ketosis.