What is Ketosis
Typically a major form of fuel for the body is glucose, which is the end result of the breakdown of carbohydrate. Ketosis is a metabolic state in which the body shifts to using fat as its primary fuel source. It is called ketosis because the actual fuel made by fat breakdown are molecules referred to as ketone bodies.
The body begins to break down fat any time it needs fuel but there is not enough available carbohydrate. This can occur after a period of fasting, starvation, if an insulin dependent diabetic goes too long without insulin, or intentionally by eating a very low carbohydrate diet. In all of these conditions your body is deprived of carbohydrates long enough to have burned through all of its glycogen (the storage form of glucose in your muscle and liver) stores.
Why People Participate in Ketosis
There are a few different reasons and arguments for intentionally entering and maintaining a ketogenic state.
Ketogenic diets are used in the treatment of epilepsy and are being studied in relation to several other disease states.
For epilepsy , ketosis has been shown to control seizure activity as well or better than pharmaceuticals. For a variety of reasons, ketosis is often only prescribed after 5 or more anti-seizure medications have been tried and failed.
Though there is less evidence, some evidence exists for the treatment of many other disease states with ketosis including polycystic ovarian syndrome, Alzheimer’s and Parkinson’s diseases, sleep disorders, cancer, autism, multiple sclerosis (MS), head aches, various neurological disorders, acne, and amyotrophic lateral sclerosis (ALS).
Probably the most popular use for ketosis is weight loss. Because the process of getting fuel from fat is less efficient than getting it from carbohydrate, ketosis is a very efficient method for losing weight. If an individual continues to eat fewer calories than their estimated needs, they should lose fat percentage relatively quickly because not only is the food being eaten poorly utilized, but the go-to fuel source for someone in ketosis is fat.
There is some evidence and some anecdotal accounts of ketosis enabling enhanced athletic performance. The theory behind this increase is that under standard conditions, the body relies on recently ingested foods and then stored glycogen for fuel during prolonged exercise. When the body’s glycogen stores are depleted, it has to start breaking down fat or protein for energy. When not in a state of ketosis, this process does not work very quickly and so is not truly feasible for providing energy quickly enough to be suitable for athletic performance. Alternately, when the body is adapted to a ketotic state, fat is more quickly burned for energy during times of need. Therefore, an athlete should be able to continue an activity longer without the need to refuel.
How Does One Achieve Ketosis
Depending on your specific physiology, carbohydrate sensitivity, glycogen stores, and carbohydrate intake, getting into ketosis could take from 1-3 days. Typically a daily intake of no more than 30 grams of carbohydrate will achieve ketosis in 2 days. However, it may take up to three weeks for the body to fully adjust to the metabolic shift and begin to preferentially burn fat for fuel. There are some unpleasant symptoms associated with the first few days of carbohydrate restriction including a “foggy” head, headache, and muscle weakness. Much of this unpleasantness varies from person to person and can be somewhat mitigated by supplementing with minerals (at least sodium and possibly potassium and magnesium) to keep electrolyte balance in order.
As far as the nuts and bolts, a ketogenic diet is one that is very low in carbohydrate, high in fat, and moderate in protein. That is, the diet should consist of roughly less than 30 grams carbohydrate, 75% fat, and the rest from protein.
Over the course of the next five weeks I will be providing updates of my own experience in ketosis, which will be useful to myself as a dietitian and hopefully also useful to anyone considering a ketogenic diet.