In ketogenesis, two acetyl-CoA molecules instead condense to form acetoacetyl-CoA via thiolase. Acetoacetyl-CoA momentarily combines with another acetyl-CoA via HMG-CoA synthase to form hydroxy-β-methylglutaryl-CoA. Hydroxy-β-methylglutaryl-CoA form the ketone body acetoacetate via HMG-CoA lyase. Acetoacetate can then reversibly convert to another ketone body—D-β-hydroxybutyrate—via D-β-hydroxybutyrate dehydrogenase. Alternatively, acetoacetate can spontaneously degrade to a third ketone body (acetone) and carbon dioxide, although the process generates much greater concentrations of acetoacetate and D-β-hydroxybutyrate. When blood glucose levels are low, ketone bodies can be exported from the liver to supply crucial energy to the brain.[28]

A study in the Journal of Applied Physiology showed that people who do twice-a-day workouts, but defy standard nutrition recommendations by not eating for two hours after the first session (thus depleting carbohydrate stores with the first session) experienced a better ability to burn fat (with no loss in performance) compared with a group that trained only once a day and ate carbohydrates afterward.
First, I want to thank you for all of your dedication and work in providing this site. The difficulty of maintaining a healthy weight is a big problem for so many people. My personal question & issue in staying on Keto is my craving for fresh fruit. This a.m I had a large fresh peach along with my “Bullet Proof” coffee. Have I now sabotaged today’s Keto eating?
In addition, most studies that compare carbohydrate utilization with fat utilization fail to take into account the fact that full “fat adaptation” that allows you to gain all the benefits of using fat as a fuel actually takes time – often more than four weeks – and up to a couple years. But since most studies that compare fat and carbohydrate burning are short-term, you rarely see the benefits of this kind of fat adaptation actually fleshed out in research. Instead, the average research participant begins the study in a non-fat adapted state, gets either a high fat or high carb diet, then launches into exercise. But in an ideal study, that person would have followed either a high-fat or high-carb diet for many months before getting their fat burning capability investigated.
Hi Kelly, All packaged foods will have a nutrition label that list the macros per serving, including fat, protein and cabrohydrates. Net carbs, which is what most people look at for low carb and keto, are total carbs (the amount on the label) minus fiber and sugar alcohols, as explained in the article above. I have a low carb food list here that gives you a full list of all the foods you can eat, and the net carbs in each. You can also sign up above to be notified about the meal plans, which are a great way to get started.
Those issues can be part of what's known as the “keto flu,” Warren says. Other side effects of the keto diet, all of which are tied to carb withdrawal, can include lightheadedness, nausea, mental fog, cramps, and headaches, in addition to tiredness. Luckily, the keto flu doesn't usually last more than a week—which is coincidentally about when people start to see the number on the scale go down, says Warren.

Carbohydrates help control blood sugar levels, which are of particular importance for people with diabetes. A study published in May 2018 in the journal Diabetic Medicine shows that while a keto diet may help control HbA1c levels (a two- to three-month average of blood sugar levels), the diet may also cause episodes of hypoglycemia, which is a dangerous drop in blood sugar. Echoing many registered dietitians, the Lincoln, Nebraska–based sports dietitian Angie Asche, RD, says she is “hesitant to recommend a ketogenic diet for individuals with type 1 diabetes.”
Now I though about taking keto supplement to boost my ketosis (I’m also looking to boost my overall electrolyte and vitamin/mineral). I’m unsure what product to take. Should I take keto os or ketocana (or else)? Should I take it in the morning while I’m empty stomack for the next 6 hours (wake up at 5) with my mg cap so I get a boost in electrolyte and keto in the morning? Should I take more? Depending on the set, I might not have to take mg cap anymore since they all include some in it.
Ben, great article! I recently did my own ketosis experiment and didn’t catch the 100-200g advise until later than I should have, I’m guessing. Great results for 1-2 months but after 3 months I quit sleeping through the night and would wake after about 4 hours of rest each night. My guess is that the extra carbs at night coupled with iodine supplements should allow me to “have my cake and eat it too?” Any other suggestions on the sleep issue? I’ve gone back to High Fat/Low Carb, have improved sleep but I do miss nutritional ketosis and want to try again once my sleep is stable. Thank YOU!!!
If you are already in ketosis and accustomed to high-fat, low-carb diets, you can take one heaping scoop in about eight ounces of water fifteen minutes prior to working out. It stays in your system and will provide your body with elevated ketone levels for about three hours. When taken as a pre-workout, KetoCaNa has also been shown to decrease the amount of oxygen consumed at a given power output.

A small Feb. 20, 2017, study looked at the impact of a six-week ketogenic diet on physical fitness and body composition in 42 healthy adults. The study, published in the journal Nutrition & Metabolism, found a mildly negative impact on physical performance in terms of endurance capacity, peak power and faster exhaustion. Overall, researchers concluded, “Our findings lead us to assume that a [ketogenic diet] does not impact physical fitness in a clinically relevant manner that would impair activities of daily living and aerobic training.” The “significant” weight loss of about 4.4 pounds, on average, did not affect muscle mass or function.


The ketogenic diet reduces seizure frequency by more than 50% in half of the patients who try it and by more than 90% in a third of patients.[18] Three-quarters of children who respond do so within two weeks, though experts recommend a trial of at least three months before assuming it has been ineffective.[9] Children with refractory epilepsy are more likely to benefit from the ketogenic diet than from trying another anticonvulsant drug.[1] Some evidence indicates that adolescents and adults may also benefit from the diet.[9]
Whether ketosis is taking place can be checked by using special urine test strips such as Ketostix. The strips have a small pad on the end, which the user dips in a fresh urine specimen. Within seconds, the strip changes color to indicate the level of acetoacetate ketone bodies, which reflects the degree of ketonuria, which, in turn, gives a rough estimate of the level of hyperketonemia in the body (see table below). Alternatively, some products targeted to diabetics such as the Abbott Precision Xtra or the Nova Max can be used to take a blood sample and measure the β-hydroxybutyrate ketone levels directly. Normal serum reference ranges for ketone bodies are 0.5–3.0 mg/dL, equivalent to 0.05–0.29 mmol/L.[29]
Keto-adaption is a complex set of metabolic processes in which the body shifts from using primarily glucose for energy to using largely ketones and fat for energy. Achieving ketosis doesn’t mean the body is maximizing the use of these ketones; it takes longer than a few days for the body to get used to burning fat and ketones as its predominant fuels.
Long-term disruption of menstruation can bring on serious side effects, including low bone density. “This is because estrogen is very important to bone health,” says Yawitz. “Studies have also found prolonged menstrual irregularity to increase risk for cardiovascular disease, depression, anxiety, and sexual dysfunction. It’s important to contact your ob-gyn if your cycles become irregular or if you stop having periods.”

As a matter of fact, from a pure biology perspective, lauric acid should actually be considered a LCT, because unlike C8 and C10 forms of MCT, lauric acid gets processed by your liver. This matters because your body metabolizes MCT’s differently than LCT’s: unlike LCT’s, MCT’s get very quickly converted into ketone energy to fuel your brain and body instead of requiring a pit stop in the liver for processing.

As insulin levels plummet from carb-cutting, more water is flushed out, along with excess sodium (in contrast, excess insulin from carbs causes sodium and water retention).4 In some people, dehydration contributes to constipation, which can also result from avoiding fiber-rich carbohydrate foods. While less common, diarrhea or loose bowels can be triggered by a number of factors including too much or too little fat, dairy intolerance, or changes in gut flora. 
Amazing article – gonna have to print it and read it again. To much to break down in one sitting. Thanks Ben – you’ve pulled together so much insight and references that’s given me greater confidence and conviction. I’m 50 and use to be super active and a seasoned athlete but after a few ‘mid life surgical interventions’ I had to find a better way… Ketogenics has been that for me… no more inflammation… I can’t tell you how great it’s been to be pain free! Keep leading from the front.
The presence of abnormally high levels of KETONES in the blood. These are produced when fats are used as fuel in the absence of carbohydrate or available protein as in DIABETES or starvation. Ketosis is dangerous because high levels make the blood abnormally acid and there is loss of water, sodium and potassium and a major biochemical upset with nausea, vomiting, abdominal pain, confusion, and, if the condition is not rapidly treated, coma and death. Mild ketosis also occurs in cases of excessive morning sickness in pregnancy.
In sheep, ketosis, evidenced by hyperketonemia with beta-hydroxybutyrate in blood over 0.7 mmol/L, occurs in pregnancy toxemia.[78][79] This may develop in late pregnancy in ewes bearing multiple fetuses,[78][79] and is associated with the considerable glucose demands of the conceptuses.[80][81] In ruminants, because most glucose in the digestive tract is metabolized by rumen organisms, glucose must be supplied by gluconeogenesis,[82] for which propionate (produced by rumen bacteria and absorbed across the rumen wall) is normally the principal substrate in sheep, with other gluconeogenic substrates increasing in importance when glucose demand is high or propionate is limited.[83][84] Pregnancy toxemia is most likely to occur in late pregnancy because most fetal growth (and hence most glucose demand) occurs in the final weeks of gestation; it may be triggered by insufficient feed energy intake (anorexia due to weather conditions, stress or other causes),[79] necessitating reliance on hydrolysis of stored triglyceride, with the glycerol moiety being used in gluconeogenesis and the fatty acid moieties being subject to oxidation, producing ketone bodies.[78] Among ewes with pregnancy toxemia, beta-hydroxybutyrate in blood tends to be higher in those that die than in survivors.[85] Prompt recovery may occur with natural parturition, Caesarean section or induced abortion. Prevention (through appropriate feeding and other management) is more effective than treatment of advanced stages of ovine ketosis.[86]
And for everyone else, your desire to get slim and toned isn’t going to hold up -- it’s going to hurt you. If or when you get to the body that you believed you desperately desired you’re probably still not going to be answering “why?” with “I want to have a healthy relationship with food” or “I want to be healthy.” Your answer is going to be “I am restricting my eating because I think a certain weight or aesthetic is going to make me happy,” and when that weight doesn’t make you happy (because life is filled with highs and lows that physical attraction cannot control) you’re going to break and return to your previous relationship with food, only then the cravings will be twice as vicious because you have deprived yourself, and because you are ashamed.
Fascinating stuff and I am quite curious how we know for certain one is actually in ketosis i.e. using ketones as primary fuel source BECAUSE we do know that glucose has a shorter metabolic pathway to burn and under most conditions, given the presence of glucose, that is what the body will default to which is why high fat and high sugar together in diet is so detrimental. So if we use one or more of the above “boosters” and show high levels of blood ketones but also highish levels of glucose (during initial transition) will be mostly burning ketones or still defaulting to glucose?
But people who started following the keto diet noticed weight loss for a few reasons: When you eat carbs, your body retains fluid in order to store carbs for energy (you know, in case it needs it). But when you’re not having much in the carb department, you lose this water weight, says Warren. Also, it's easy to go overboard on carbohydrates—but if you're loading up on fat, it may help curb cravings since it keeps you satisfied.

Yes, they're technically a fruit, but we think olives deserve a shout-out all of their own, since they're also a great source of healthy fats and are one of a few keto-approved packaged foods. Plus, they're a great source of antioxidants, will satisfy your craving for something salty, and are blissfully low-carb. “About a palm's worth only has 3 grams of net carbs,” Sarah Jadin, RD, told Health in a previous interview.
The addition of MCT powder to ketones serves the purpose of maintaining endogenous production of ketone bodies by stimulating fatty acid oxidation in the liver, which then causes the production of even more ketone bodies. In this transcript from a podcast with Dr. Dom D’Agostino it is mentioned that MCT’s cross the blood-brain barrier straight to the brain. So not only are the ketones being used by the brain as an alternative fuel but so are MCT’s.

Can’t get enough of avocados? You now have a great excuse to eat more of them. A ½-cup serving of the creamy fruit has almost 12 g of fat and only 2.6 g of net carbs. Avocados are also low in calories (about 138 for the same serving), making them an ideal snack in between meals. One serving also has about 6.4 g of dietary fiber (25.6 percent daily value, or DV), 404 milligrams (mg) of potassium (8.6 percent DV), and only 2.8 g of sugar. Try topping your salad with cubed avocado for a keto-friendly lunch.

Can’t get enough of avocados? You now have a great excuse to eat more of them. A ½-cup serving of the creamy fruit has almost 12 g of fat and only 2.6 g of net carbs. Avocados are also low in calories (about 138 for the same serving), making them an ideal snack in between meals. One serving also has about 6.4 g of dietary fiber (25.6 percent daily value, or DV), 404 milligrams (mg) of potassium (8.6 percent DV), and only 2.8 g of sugar. Try topping your salad with cubed avocado for a keto-friendly lunch.

The question then is whether your crotch is like your mouth. Not in general, but in the specific case of ketones. That is, when you are on the keto diet, can ketones also accumulate in your crotch area and then subsequently lead to a new smell? Moreover, if you are woman, could ketones be changing the acidity of your vagina, which then may produce an environment more favorable to certain types of microorganisms? Indeed, the smell of your vagina can depend on the composition of microorganisms there. Some odors, like a strong fishy one, can be the result of an overgrowth of certain microorganisms like bacteria, which is the case in bacterial vaginosis.

I have been taking Ucan 30 Minutes before run and take UCAN 1 Hour into run and 1 hour later. Also take BCAA powder in 8 ounce liquid during run. I have been doing HFAT and LCARB diet. Problem i slow down after 1 1/2 hour during my long run. I need your advice help fueling my run after 14 miles. This my first Marathon, I have run 7 Half Marathon around 1.58.
Fascinating stuff and I am quite curious how we know for certain one is actually in ketosis i.e. using ketones as primary fuel source BECAUSE we do know that glucose has a shorter metabolic pathway to burn and under most conditions, given the presence of glucose, that is what the body will default to which is why high fat and high sugar together in diet is so detrimental. So if we use one or more of the above “boosters” and show high levels of blood ketones but also highish levels of glucose (during initial transition) will be mostly burning ketones or still defaulting to glucose?
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