Ketosis - Controversy

Controversy

Some clinicians regard restricting a diet from all carbohydrates as unhealthy and dangerous. However, it isn't necessary to completely eliminate all carbohydrates from the diet in order to achieve a state of ketosis. Other clinicians regard ketosis as a safe biochemical process that occurs during the fat-burning state. Ketogenesis can occur solely from the byproduct of fat degradation: acetyl-CoA. Ketosis, which is accompanied by gluconeogenesis (the creation of glucose de novo from pyruvate), is the specific state with which some clinicians are concerned. However, it is unlikely for a normal functioning person to reach life-threatening levels of ketosis, defined as serum beta-hydroxybutyrate (B-OHB) levels above 15 millimolar (mM) compared to ketogenic diets among non diabetics which "rarely run serum B-OHB levels above 3 mM." This is avoided with proper basal secretion of pancreatic insulin. People who are unable to secrete basal insulin, such as type I diabetics and long-term type II diabetics, are liable to enter an unsafe level of ketosis, causing an eventual comatose state that requires emergency medical treatment.

The anti-ketosis conclusions have been challenged by a number of doctors and advocates of low-carbohydrate diets, who dispute assertions that the body has a preference for glucose and that there are dangers associated with ketosis. Because of the experience of Arctic explorers like Vilhjalmur Stefansson who adopted native Inuit diets which derived as much as 90% of energy from fats and proteins, many have held up the Inuit people as an example of a culture that has lived for thousands of years on a ketogenic diet. Conversely, it is speculated by Nick Lane that the Inuit may have a genetic predisposition allowing them to eat a ketogenic diet and remain healthy. According to this view, such an evolutionary adaptation would have been caused by environmental stresses. This speculation is unsupported, however, in light of the many arctic explorers including John Rae, Fridtjof Nansen, and Frederick Schwatka all of whom adapted to native ketogenic diets with no adverse effects. Note especially Schwatka, who specifically commented that after a 2- to 3-week period of adaptation to the ketogenic diet of the native peoples he could manage "prolonged sledge journeys," including the longest sledge journey on record, relying solely on the Inuit diet without difficulty. Furthermore, in a comprehensive review of the anthropological and nutritional evidence collected on 229 hunter-gatherer societies it was found that, "Most (73%) of the worldwide hunter-gatherer societies derived >50% (≥56–65% of energy) of their subsistence from animal foods, whereas only 14% of these societies derived >50% (≥56–65% of energy) of their subsistence from gathered plant foods," suggesting that the ability to thrive on ketogenic diets is widespread and not limited to any particular genetic predisposition. While it is believed that carbohydrate intake after exercise is the most effective way of replacing depleted glycogen stores, studies have shown that, after a period of 2–4 weeks of adaptation, physical endurance (as opposed to physical intensity) is unaffected by ketosis, as long as the diet contains high amounts of fat. It seems appropriate that some clinicians have acknowledged this period of keto-adaptation the "Schwatka Imperative" after the explorer who first identified the transition period from glucose-adaptation to keto-adaptation.