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, relative to carbohydrates. Some clinicians refer to this period of keto-adaptation as the "Schwatka imperative" after Frederick Schwatka, the explorer who first identified the transition period from glucose-adaptation to keto-adaptation.
But the real problem isn’t going over your carb limit—it’s the protein. A therapeutic keto diet limits your protein intake “If you’re eating a lot of protein, you’re breaking that down into carbs,” Giancoli explains. Your body is in desperation mode on keto, she says, and without a reasonable supply of carbohydrates coming from grains and fruits, you’ll start breaking down the amino acids in proteins to make glucose. Glucose, though it sounds like a scary sugar, is your body’s primary source of fuel. Too much isn’t good for you, but you need some just to allow your cells to function normally.
In dairy cattle, ketosis is a common ailment that usually occurs during the first weeks after giving birth to a calf. Ketosis is in these cases sometimes referred to as acetonemia. A study from 2011 revealed that whether ketosis is developed or not depends on the lipids a cow uses to create butterfat. Animals prone to ketosis mobilize fatty acids from adipose tissue, while robust animals create fatty acids from blood phosphatidylcholine (lecithin). Healthy animals can be recognized by high levels of milk glycerophosphocholine and low levels of milk phosphocholine. Point of care diagnostic tests are available and are reasonably useful.
There are vegetables that are high in carbs and others low in carbs. The keto diet recommends sticking to the ones low on carbs but encourages you to eat a lot of them. Best vegetables are all green ones to make it easy. And vegetables that grow above the ground (e.g. lettuce) are always better than the ones that grow below the ground (e.g. potatoes)
Acetyl-CoA can be metabolized through the TCA in any cell, but it can also undergo a different process in liver cells: ketogenesis, which produces ketone bodies. Ketone bodies are also produced in mitochondria, and usually occur in response to low blood glucose levels. When glucose levels are low, oxaloacetate is diverted away from the TCA cycle and is instead used to produce glucose de novo (gluconeogenesis). But when oxaloacetate is unavailable to condense with acetyl-CoA, acetyl-CoA cannot enter the cycle, and so the body has evolved an alternative way to harvest energy from it.
The notion that the Atkins Nutritional Approach - high in protein, which builds muscle, and fat, which is used for energy - will force your body to break down muscle is incorrect. Only individuals on very low-calorie diets can lose muscle mass, because they have an inadequate protein intake. Atkins, however, is not calorie restricted (this isn't an invitation for gorging, but a recommendation to eat until you are no longer hungry) and the high protein intake required offsets any possible loss of body mass.
^ Jump up to: a b c Taboulet P, Deconinck N, Thurel A, Haas L, Manamani J, Porcher R, Schmit C, Fontaine JP, Gautier JF (April 2007). "Correlation between urine ketones (acetoacetate) and capillary blood ketones (3-beta-hydroxybutyrate) in hyperglycaemic patients". Diabetes & Metabolism. 33 (2): 135–9. doi:10.1016/j.diabet.2006.11.006. PMID 17320448.
One downside to a ketogenic diet for weight loss is the difficulty maintaining it. “Studies show that weight loss results from being on a low-carb diet for more than 12 months tend to be the same as being on a normal, healthy diet,” says Mattinson. While you may be eating more satiating fats (like peanut butter, regular butter, or avocado), you’re also way more limited in what’s allowed on the diet, which can make everyday situations, like eating dinner with family or going out with friends, far more difficult. Because people often find it tough to sustain, it’s easy to rely on it as a short-term diet rather than a long-term lifestyle.