Ketosis is an energy state that your body uses to provide an alternative fuel when glucose availability is low.  It happens to all humans when fasting or when carbohydrate intake is lowered.  The process of creating ketones is a normal metabolic alternative designed to keep us alive if we go without food for long periods of time. Eating a diet low in carb and higher in fat enhances this process without the gnawing hunger of fasting.
You can have a completely smooth transition into ketosis, or…not. While your body is adapting to using ketones as your new fuel source, you may experience a range of uncomfortable short-term symptoms. These symptoms are referred to as “the keto flu.” Low-sodium levels are often to blame for symptoms keto flu, since the kidneys secrete more sodium when you’re in ketosis, says Volek. A few side effects:
While it is believed that carbohydrate intake after exercise is the most effective way of replacing depleted glycogen stores,[72][73] 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.[74] 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.[75]
Alcoholic ketoacidosis (AKA) presents infrequently, but can occur with acute alcohol intoxication, most often following a binge in alcoholics with acute or chronic liver or pancreatic disorders. Alcoholic ketoacidosis occurs more frequently following methanol or ethylene glycol intoxication than following intoxication with uncontaminated ethanol.[11]
Diabetic ketoacidosis occurs when ketone levels become too high and poison the body. This condition is more common in people with type 1 diabetes because their bodies don’t make insulin. In the event that their ketone level rises, their bodies are unable to produce insulin to slow down this production. If left untreated, this condition can lead to a diabetic coma or death.
"Plenty of people jump right in, thinking all they have to do is cut carbs and increase fat. All of a sudden, they hit a wall and get 'keto flu.' They feel tired, lethargic, and experience headaches," Wittrock says. "The primary reason they get these symptoms is lack of the three primary electrolytes: sodium, potassium, and magnesium. If you're deficient in any of these, you'll suffer mentally and physically. This is the single biggest reason people fail on the keto diet."

The Inuit are often cited as an example of a culture that has lived for hundreds of years on a low-carbohydrate diet.[42] However, in multiple studies the traditional Inuit diet has not been shown to be a ketogenic diet.[43][44][45][46] Not only have multiple researchers been unable to detect any evidence of ketosis resulting from the traditional Inuit diet, but the ratios of fatty-acid to glucose were observed at well below the generally accepted level of ketogenesis.[44][47][45][46] Furthermore, studies investigating the fat yields from fully dressed wild ungulates, and the dietary habits of the cultures who rely on them, suggest that they are too lean to support a ketogenic diet.[48][49] With limited access to fat and carbohydrates, cultures such as the Nunamiut Eskimos—who relied heavily on caribou for subsistence—annually traded for fat and seaweed with coastal-dwelling Taremiut.[48]
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.[27] Ketone bodies are also produced in mitochondria, and usually occur in response to low blood glucose levels.[28] 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.
As is in the case of GABA, the intracellular reactive oxygen species (ROS) hypothesis works against the hunger-suppressive role of KD: it has been demonstrated that the hypothalamic ROS increase through NADPH oxidase is required for the eating-inhibitory effect of insulin (Jaillard et al., 2009); moreover it has been demonstrated that there is a ROS-dependent signaling pathway within the hypothalamus that regulates the energy homeostasis, and that activation of ROS-sensitive mechanisms could be sufficient to promote satiety (Benani et al., 2007). On the other side, KBs decreases mitochondrial production of ROS by increasing NADH oxidation in the mitochondrial respiratory chain (Maalouf et al., 2007).
What a great post. I thought i would add about the selection of food you eat on keto and that everyone is different. Some food gives you energy and some doesnt, this varies person to person. I started and quit keto 3 times before i managed to find my balance. The first few times it made be poorly, from the shock of diet change. However, you can wean yourself into the diet which i did the last time when i had the most success.
So how does this work? A quick run-through: The first tip was to eat low carb. This is because a low-carb diet lowers your levels of the fat-storing hormone insulin, allowing your fat deposits to shrink and release their stored energy. This tends to cause you to want to consume less calories than you expend – without hunger – and lose weight. Several of the tips mentioned above are about fine-tuning your diet to better this effect.
Jump up ^ Lockyer, Christina (1991). "Body composition of the sperm whale, Physeter cation, with special reference to the possible functions of fat depots" (PDF). Journal of the Marine Research Institute. 12 (2). ISSN 0484-9019. Retrieved 2014-04-25. The significant levels of carbohydrate, probably mostly in the form of glycogen, in both blubber and muscle, may represent an instant form of energy for diving via anaerobic glycolysis.
Some clinicians[37] regard eliminating carbohydrates as unhealthy and dangerous.[38] However, it is not necessary to eliminate carbohydrates from the diet completely to achieve ketosis. Other clinicians regard ketosis as a safe biochemical process that occurs during the fat-burning state.[35] Ketosis, which is accompanied by gluconeogenesis (the creation of glucose de novo from pyruvate), is the specific state that concerns some clinicians. However, it is unlikely for a normally 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."[39] This is avoided with proper basal secretion of pancreatic insulin. People who are unable to secrete basal insulin, such as type 1 diabetics and long-term type II diabetics, are liable to enter an unsafe level of ketosis, eventually resulting in a coma that requires emergency medical treatment.[citation needed] 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.[40][41]
I can’t think of a more traditional appetizer recipe than sausage balls. They have grazed countless holiday tables for decades. These keto sausage balls are the perfect low carb rendition of a high carb classic. In this recipe I used almond flour in place of the traditional bisquick used in the sausage ball recipes of old. It makes the perfect substitution, while keeping the perfectly dense, juicy texture.
Dinner: In a small sauce pan bring 2-3 cups of water to the boil. Cook a large egg in rolling boil for 5 minutes, then transfer to ice bath (a bowl with cold water and ice cubes in it). Wash and spin dry butter lettuce, top with sliced avocado and hemp seed. Serve soft boiled egg with cherry tomatoes, butter lettuce salad and mayonnaise as dressing.

This week we’re introducing a slight fast. We’re going to get full on fats in the morning and fast all the way until dinner time. Not only are there a myriad of health benefits to this, it’s also easier on our eating schedule (and cooking schedule). I suggest eating (rather, drinking) your breakfast at 7am and then eating dinner at 7pm. Keeping 12 hours between your 2 meals. This will help put your body into a fasted state.

Jump up ^ Lawrie 2014, pp. 92-. "A much delayed onset of rigor mortis has been observed in the muscle of the whale (Marsh, 1952b). The ATP level and the pH may remain at their high in vivo values for as much as 24h at 37ºC. No adequate explanation of this phenomenon has yet been given; but the low basal metabolic rate of whale muscle (Benedict, 1958), in combination with the high content of oxymyoglobin in vivo (cf 4.3.1), may permit aerobic metabolism to continue slowly for some time after the death of the animal, whereby ATP levels can be maintained sufficiently to delay the union of actin and myosin in rigor mortis."
Being in optimal ketosis for a prolonged period of time (say, a month) will ensure that you experience the maximal hormonal effect from eating a low-carb diet. If this doesn’t result in noticeable weight loss, you can be certain that too many carbs are NOT part of your weight issue and not the obstacle to your weight loss. There are, in fact, other causes of obesity and being overweight. The next three tips in this series might help you.
Two comments: first of all, I’ve only discovered your site recently because (a) I. no longer eat refined sugar, and (b) after a year of no ice cream, I bought an ice cream maker and am making maple syrup sweetened ice cream, with varied success, which brings me to my comments/questions: first, this recipe calls for xylitol or erythritol, and as a person with three dogs, may I just mention that dogs can be killed by consuming xylitol. For this reason, I don’t use it, because they adore ice cream, and I can’t resist giving them a little occasionally…and I might forget. This is important!! Second: I keep reading coconut milk ice cream recipes (and others as well) that jump up and down and insist that these recipes makes this amazing, creamy ice cream, and….it doesn’t. I have made ice cream with coconut milk (full-fat) And coconut cream and it is usually icy, if delicious. Not creamy. Same for my one or two forays into making dairy ice cream to see how that would work. All of it is full of ice crystals and while it may be delicious, creamy it is not, although ice cream made with cashews and plant milk does pretty well. My theory is that commercial ice cream is filled with chemicals and stabilizers and the like, and is therefore what we call creamy. All the ice cream I have made with my Cuisinart ice cream maker freezes hard as a rock, and again–while it may be delicious, it is NOT creamy. Is it possible that I’m doing something wrong? I can’t see that I’m doing anything differently from the various vegan and/or dairy recipes I’ve seen. I’ve used both maple sugar and maple syrup for sweetening, as well as occasionally coconut sugar. My most successful ice cream has been made with plant milk and maple syrup. Getting everything as cold as possible before freezing helps, of course, but it is NEVER creamy. Thoughts?

Achieving optimal ketosis hinges on finding the right balance of macronutrients (or “macros” in keto-speak); these are the elements in your diet that account for the majority of your calories, a.k.a. energy—namely, fat, protein, and carbohydrates. By the way, it’s often “net grams” of carbohydrates that are counted toward your daily intake; “net” deducts the amount of fiber in a food from its carbohydrate total.

Moreover, in the above study of Sumithran et al. (2013), ketosis maintains post-prandial secretion of CCK as previously demonstrated by other researchers (Chearskul et al., 2008). Note that the orexigenic effect of BHB is blocked by transection of the common hepatic branch of the vagus nerve (Langhans et al., 1985). The hepatic branch contains fibers from the proximal small intestine, stomach and pancreas, and is sensitive to CCK (Horn and Friedman, 2004); ghrelin signals to brain are also transmitted via vagus nerve (Habara et al., 2014). Thus, the effects of ketosis on these two appetite-related hormones could be one of the many factors related to the effects of such nutritional regimen on food control.
Jump up ^ Greenberg CR, Dilling LA, Thompson GR, Seargeant LE, Haworth JC, Phillips S, Chan A, Vallance HD, Waters PJ, Sinclair G, Lillquist Y, Wanders RJ, Olpin SE (April 2009). "The paradox of the carnitine palmitoyltransferase type Ia P479L variant in Canadian Aboriginal populations". Molecular Genetics and Metabolism. Molecular Genetics and Metabolism. 96 (4): 201–7. doi:10.1016/j.ymgme.2008.12.018. PMID 19217814.
I am a stage four kidney disease patient. I am also a type one diabetic. I have had diabetes for 37 years. My Internist suggested the Keto diet for me, but there are so many if the foods on the Keto diet that I’m not able to eat because of my kidneys functioning at 22%. How do I reconcile this diet plan to work with my kidney disease? I’m not allowed any dairy, because of my high potassium. Is almond milk ok to drink? I’m not allowed avocados, mushrooms, spinach, tomatoes, greens, (beet or chard). No bacon, or pork. No melons, bananas, oranges, peaches, pears, some apples, pineapple. I can have berries of all kinds. will this still work for me?
If you would like to read more on ketogenic diets and ketosis, Jeff Volek and Steve Phinney discuss the new method of checking blood ketones in their book "The Art and Science of Low Carbohydrate Performance", and they also offer another good book "The Art and Science of Low Carbohydrate Living", which is a good book for those who need an introduction to the science of ketogenic diets. 
Normal body cells metabolize food nutrients and oxygen during cellular “respiration”,  a set of metabolic pathways in which ATP (adenosine triphosphate), our main cellular energy source is created. Most of this energy production happens in the mitochondria, tiny cell parts which act as powerhouses or fueling stations. There are two primary types of food-based fuel that our cells can use to produce energy:
Jump up ^ Hochachka PW, Storey KB (February 1975). "Metabolic consequences of diving in animals and man". Science. 187 (4177): 613–21. Bibcode:1975Sci...187..613H. doi:10.1126/science.163485. PMID 163485. In the terminal stages of prolonged diving, however, even these organs must tolerate anoxia for surprisingly long times, and they typically store unusually large amounts of glycogen for this purpose.
A reduced availability of dietary carbohydrates leads to an increased liver production of KBs. The liver cannot utilize KBs because it lacks the mitochondrial enzyme succinyl-CoA: 3-ketoacid (oxoacid) CoA transferase (SCOT) necessary for activation of acetoacetate to acetoacetyl CoA. KBs are utilized by tissues, in particularly by brain. KBs enter the citric acid cycle after being converted to acetyl CoA by hydroxybutyrate dehydrogenase (HBD), succinyl-CoA: 3–CoA transferase (SCOT), and methylacetoacetyl CoA thiolase (MAT). Modified from Owen (2005), Paoli et al. (2014).
^ 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.

You’re very welcome, Judy! I’m glad it’s helpful. If you are keto (as opposed to low carb), unfortunately peaches would not allow you to stay in ketosis. You can check my keto food list to help determine what is keto friendly. Of course, there are worse things than fresh fruit 🙂 but in the end our bodies still see the sugar. That being said, it doesn’t mean you sabotaged the whole day. Just pick up again – you got this!! (And for next time, try some fresh berries in moderation when you’re craving fruit.)

Hey there! Welcome to my site! I am Kyndra Holley - International Best Selling Cookbook Author, and the face behind this blog. I am an avid lover of all things low carb and gluten free. I focus on real, whole food ingredients that you can find at your local grocer. I am a lifter of heavy things, world traveler, obsessed dog mom, hiker, essential oiler, nature lover, just to name a few. I believe that kindness is king! Read more...

Initially you may be surprised that on keto diets you eat less frequently.  That’s because the fats are pretty satisfying. But as you normalize and adjust into a ketogenic state, that may change and your appetite may increase.  That’s fine and completely normal.  Use whatever diet you decide to follow as a starting point – it should be “written in pencil” so that you can make changes along the way.  Consider adding an extra meal, marginally increasing the size of the meals or just adding a shake between meals.  It’s up to you – just listen to your body.  For example for me, I added a low-carb “green powder” shake supplement to my regimen along with either flax seed oil or some nuts in order to satisfy my hunger.

One thing many people love about keto diet meal plans is that tracking your food is optional. "One of the biggest benefits of the ketogenic diet is that there's no need to meticulously track your calories like you may in other diets," notes Dr. Josh Axe, D.N.M., C.N.S., D.C., founder of, best-selling author of Eat Dirt, and cofounder of Ancient Nutrition. "Because you're filling up on fat and protein, you're more likely to feel satisfied and energized all day long, which causes you to naturally eat less." This isn't to say that food tracking on keto is discouraged. "Some people may find calorie counting a useful tool to be more mindful and aware of what they're eating, but it's not necessary on the ketogenic diet," says Dr. Axe, but there's no need to get too stressed about hitting a certain caloric goal, especially if you're not trying to lose weight. (Related: The #1 Reason to Stop Counting Calories)