Virtually all weight loss diets to varying degrees focus on either calorie reduction or the manipulation of the intake of one of the three essential macronutrients (proteins, fats, or carbohydrates) to achieve their weight loss effects.
Ketogenic diets are a group of "high-fat, moderate protein" or "high-protein moderate fat" but very low-carbohydrate diets. The term ketogenic basically refers to the increased production of ketone bodies occasioned by the elevated rate of lipolysis (fat break down). Ketones are the acidic by-products formed during the intermediate break down of "fat" into "fatty acids" by the liver.
The first sets of ketogenic diets were actually developed as far back as the early 1920s by the Johns Hopkins Pediatric Epilepsy Center and also by Dr. R.M. Wilder of the Mayo Clinic to treat children with hard to control seizures. The diets were designed to mimic the biochemical changes that occurred during periods of fasting, namely ketosis, acidosis, and dehydration. The diets involved the consumption of about 10-15 grams of carbohydrates per day, 1 gram of protein per kilogram bodyweight of the patient and the remaining calories derived from fats.
Today, the promoters of ketogenic diets are strongly of the view that carbohydrates especially the high glycemic index ones are the major reasons why people gain weight. Carbohydrate foods are generally metabolized to produce glucose, a form of simple sugar that is generally regarded as the preferred energy source for the body as it is a faster burning energy. Although the body can break down muscle glycogen (a mixture of glucose and water) and fat to produce energy, it however prefers to get it from high glycemic index carbohydrates from diets.
Of the macronutrients, carbohydrates are therefore argued to be the major cause of weight gain. This is more so because the increased intake of high glycemic index carbohydrate foods generally causes fluctuating blood sugar levels due to their fast absorption into the bloodstream and which more often than not leads to the overproduction of insulin. This is where the problem actually starts.
Insulin is a hormone that regulates blood glucose levels and therefore maintenance of the energy in/energy out equation of the body which rules body weight. Excess amounts of glucose in the bloodstream causes the excessive secretion of insulin which leads to the storage of the excess glucose in the body as either glycogen in liver and muscle cells or fat in fat cells.
One aim of ketogenic diets is therefore to reduce insulin production to its barest minimum by drastically reducing carbohydrate consumption while using fats and proteins to supplement the body's energy requirement.
Despite the ability of ketogenic diets to reduce insulin production, their main objective is ultimately aimed at inducing the state of ketosis. Ketosis can be regarded as a condition or state in which the rate of formation of ketones produced by the break down of "fat" into "fatty acids" by the liver is greater than the ability of tissues to oxidize them. Ketosis is actually a secondary state of the process of lipolysis (fat break down) and is a general side effect of low-carbohydrate diets. Ketogenic diets are therefore favorably disposed to the encouragement and promotion of ketosis.
Prolonged periods of starvation can easily induce ketosis but it can also be deliberately induced by making use of a low-calorie or low-carbohydrate diet through the ingestion of large amounts of either fats or proteins and drastically reduced carbohydrates. Therefore, high-fat and high-protein diets are the weight loss diets used to deliberately induce ketosis.
Essentially, ketosis is a very efficient form of energy production which does not involve the production of insulin as the body rather burns its fat deposits for energy. Consequently, the idea of reducing carbohydrate consumption does not only reduce insulin production but also practically forces the body to burn its fat deposit for energy, thereby making the use of ketogenic diets a very powerful way to achieve rapid weight loss.
Ketogenic diets are designed in such a way that they initially force the body to exhaust its glucose supply and then finally switch to burning its fat deposits for energy. Subsequent food intakes after inducing the state of ketosis are meant to keep the ketosis process running by appropriately adjusting further carbohydrate consumption to provide just the basic amount of calories needed by the body.
For example, the Atkins Diet which is obviously the most popular ketogenic diet aims to help dieters achieve what the diet calls the individual's Critical Carbohydrate Level for Maintenance (CCLM) - a carbohydrate consumption level where the dieter neither gains nor loses weight anymore.
In 2003, the Johns Hopkins treatment center came up with a modified version of the Atkins Diet protocol to treat a group of 20 children with epilepsy. After the treatment, it was observed that two-thirds experienced a significant reduction in their seizures while 9 were able to reduce their medication dosages and none developed kidney stones.
Furthermore, there are ongoing scientific studies by the National Institute of Health (NIH) concerning the effectiveness of the classic ketogenic diet and the modified versions of the Atkins Diet in helping people to lose weight and also in the treatment of epilepsy. It is equally interesting to note that the National Institute of Neurological Disorders and Stroke (NINDS) is carrying out studies on the effect of ketogenic diets and also formulating medications that will be able to produce the same effect on weight reduction.