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A lot of changes are happening in your body and you’re going to feel it! The first five to seven days can be pretty rough, but your body is getting over its dependency on sugar. During this time of transition it is essential that you supplement electrolytes. Your body is flushing out lots of water, and with that goes electrolytes. The Keto Flu can be greatly reduced if you add sodium, potassium and magnesium to your diet. Check out our supplements page for a list of electrolyte supplements we recommend. Stay on course and you’ll start feeling better in no time!

When you burn key tones as a funeral, whether they are from a supplement or whether they are the ones that your body makes, you do indeed become more efficient utilizing ketones. So that is one advantage. You are correct in that if you simply use these and you do not restrict carbohydrate intake then you're not going to get quite as much benefit. I am a fan of combining these with intermittent fasting, MCT oil, and a high-fat diet.
Hi Ben, I have a question about being in ketosis. So from what I understand, a serving of Keto os will keep you in ketosis for about 4-6 hours or so……my question is doesn’t your body have to be in constant ketosis in order to really experience the benefits of using the fat as fuel? Also, if someone is not following the Keto diet, what happens to the glucose they are still consuming if they are supposedly using ketones for energy? Also, do you see any benefit from using Keto os vs. Brain Octane? I ask because there is a significant difference in price. Thank you so much!!
2) I have a hard time eating real food soon after rides/workouts. I had used Hammer Recoverite (1scoop instead of suggest serving of 2 and add 1scoop whey isolate protein) in the past because I feel a significant difference the day after with less muscle fatigue. Then I read a previous posts on your opinion of post-workout supplementation ( https://bengreenfieldfitness.com/2013/07/what-to-… ) and I realized the primary ingredient in Recoverite is maltodextrin. Since the 2013 article, has anything changed in your research that you might suggest I add PWO to aid in the muscle fatigue/recovery? (In other words, Is there anything more healthy I can take to replace the Recoverite or should the aminos/electrolytes/carbs/MCT’s from the recipe in this article be sufficient?) Thanks in advance, I appreciate all of your work!
Stock up: Jet.com's new City Grocery service (available in select markets) makes it easy to ensure you always have keto-friendly veggies in the fridge. We love their delivery scheduling tool; simply fill your cart, then decide which day and timeframe you'd like your groceries delivered. One of our faves: Urban Roots Green Squash Veggie Noodles are great for whipping up low-carb "pasta" dishes.
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.

^ Freeman JM, Vining EP, Pillas DJ, Pyzik PL, Casey JC, Kelly LM. The efficacy of the ketogenic diet—1998: a prospective evaluation of intervention in 150 children. Pediatrics. 1998 Dec;102(6):1358–63. doi:10.1542/peds.102.6.1358. PMID 9832569. https://web.archive.org/web/20040629224858/http://www.hopkinsmedicine.org/press/1998/DECEMBER/981207.HTM Lay summary]—JHMI Office of Communications and Public Affairs. Updated 7 December 1998. Cited 6 March 2008.
What are the ideal levels of blood sugar? A blood sugar or blood glucose chart identifies ideal levels throughout the day, especially before and after meals. The charts allow doctors to set targets and monitor diabetes treatment, and they help people with diabetes to self-assess. Learn more about guidelines, interpreting results, and monitoring levels here. Read now
I am not a doctor and this is not to be taken, interpreted or construed as medical advice. If you have poor liver or gallbladder function, it can be a good idea to take care of that prior to a high fat diet, yes. But a healthy high fat diet would not cause liver issues per se. These are just my own personal thoughts and not a prescription or a diagnosis or any form of health care whatsoever.
Note: Are you a vegetarian or vegan and want to go on a ketogenic diet? It’s still possible! Just keep in mind that the dietary restrictions can sometimes be a little bit intense. Make sure to plan ahead and prepare to aid your success. To help out, we’ve published articles (with 7 day meal plans included) for both the vegetarian ketogenic diet and the vegan ketogenic diet.
It is possible to combine the results of several small studies to produce evidence that is stronger than that available from each study alone—a statistical method known as meta-analysis. One of four such analyses, conducted in 2006, looked at 19 studies on a total of 1,084 patients.[23] It concluded that a third achieved an excellent reduction in seizure frequency and half the patients achieved a good reduction.[18]
Wilder's colleague, paediatrician Mynie Gustav Peterman, later formulated the classic diet, with a ratio of one gram of protein per kilogram of body weight in children, 10–15 g of carbohydrate per day, and the remainder of calories from fat. Peterman's work in the 1920s established the techniques for induction and maintenance of the diet. Peterman documented positive effects (improved alertness, behaviour, and sleep) and adverse effects (nausea and vomiting due to excess ketosis). The diet proved to be very successful in children: Peterman reported in 1925 that 95% of 37 young patients had improved seizure control on the diet and 60% became seizure-free. By 1930, the diet had also been studied in 100 teenagers and adults. Clifford Joseph Barborka, Sr., also from the Mayo Clinic, reported that 56% of those older patients improved on the diet and 12% became seizure-free. Although the adult results are similar to modern studies of children, they did not compare as well to contemporary studies. Barborka concluded that adults were least likely to benefit from the diet, and the use of the ketogenic diet in adults was not studied again until 1999.[10][14]

Wow! Amazing article. I don’t read blogs regularly, but I’ll be reading more of yours. I am on day 11 of a fast to get me into ketosis; 7 days bone broth and now on day-4 water only. Intentions are weight loss (10# down, 15# more to go) and immunity improvement/gut help. Planning 9 days of whey water, fermented veggies and mad probiotics when the water days are done (day 14?). After this fast I want to stay fat adapted, start training again and get down to 8% body fat. I believe you have cut that journey significantly with this article. Thank you.


I'd recommend starting with glucose and hemoglobin A1C, along with a good multi like https://bengreenfieldfitness.com/multi and a fish oil like the one at greenfieldfitnesssystems.com – Anyways, I'd be happy to help you via a personal one-on-one consult. Just go to https://bengreenfieldfitness.com/coaching. and then choose a 20 or 60 minute consult, whichever you'd prefer. I can schedule ASAP after you get that.
The ketone bodies are possibly anticonvulsant; in animal models, acetoacetate and acetone protect against seizures. The ketogenic diet results in adaptive changes to brain energy metabolism that increase the energy reserves; ketone bodies are a more efficient fuel than glucose, and the number of mitochondria is increased. This may help the neurons to remain stable in the face of increased energy demand during a seizure, and may confer a neuroprotective effect.[56]
Thanks for all of the great info!! I have Hashimoto’s and would really like to try a high fat/low carb diet. You mentioned that this might not be a good option for people with thyroid issues. How do you recommend I modify my diet to lose weight taking into consideration the Hashimoto’s. I take Westhroid, a non-synthetic thyroid supplement to help with my sluggish thyroid. Thanks so much for any advice you can give me. :)
A: The most common ways to track your carbs is through MyFitnessPal and their mobile app. You cannot track net carbs on the app, although you can track your total carb intake and your total fiber intake. To get your net carbs, just subtract your total fiber intake from your total carb intake. I have written an article on How to Track Carbs on MyFitnessPal.
Because people with type 2 diabetes are at an increased risk for cardiovascular disease, there’s a specific concern that the saturated fat in the diet may drive up LDL, or “bad,” cholesterol levels, and further increase the odds of heart problems. If you have type 2 diabetes, talk to your doctor before attempting a ketogenic diet. They may recommend a different weight-loss diet for you, like a reduced-calorie diet, to manage diabetes. Those with epilepsy should also consult their doctor before using this as part of their treatment plan.
^ Bechtel PJ (2 December 2012). Muscle as Food. Elsevier Science. pp. 171–. ISBN 978-0-323-13953-3. Retrieved 19 May 2014. Freezing does stop the postmortem metabolism but only at about −18ºC and lower temperatures. Above −18ºC increasing temperatures of storage cause an increasing rate of ATP breakdown and glycolysis that is higher in the comminuted meat than in the intact tissue (Fisher et al., 1980b). If the ATP concentration in the frozen tissue falls below ~ 1 µmol/g no contraction or rigor can occur because they are prevented by the rigid matrix of ice.
Considered a symptom of the keto flu, your breath on this diet often smells fruity at first. This is because acetone is a by-product of ketosis and is eliminated mostly through the lungs and the breath, according to a study in the journal International Journal of Environmental Research and Public Health in February 2014. Acetone is a type of ketone known for having a fruity aroma in smaller concentrations. “It’s hard to say exactly how long it will last as it depends on the person, but it’s common for someone to experience this side effect for a few weeks,” says Asche.
Ketosis is a nutritional process characterised by serum concentrations of ketone bodies over 0.5 mM, with low and stable levels of insulin and blood glucose.[1][2] It is almost always generalized with hyperketonemia, that is, an elevated level of ketone bodies in the blood throughout the body. Ketone bodies are formed by ketogenesis when liver glycogen stores are depleted (or from metabolising medium-chain triglycerides[3]). Ketones can also be consumed in exogenous ketone foods and supplements.
A: The most common ways to track your carbs is through MyFitnessPal and their mobile app. You cannot track net carbs on the app, although you can track your total carb intake and your total fiber intake. To get your net carbs, just subtract your total fiber intake from your total carb intake. I have written an article on How to Track Carbs on MyFitnessPal.
Weight loss is my favorite side effect of keto. Coming in a close 2nd, 3rd, and 4th, and 5th is higher energy levels, no bingeing, clear skin, and lowered blood glucose! I don’t mind telling people that I’m Keto...or shutting down a conversation where they try and spew their online doctor degree about how I’m killing myself. This WOE work is for me, my bloodwork is the best it has ever been, and I feel great. Keto on, friends.
Once inside the mitochondrion, the dominant way that the bound fatty acids are used as fuel in cells is through β-oxidation, which cleaves two carbons off of the acyl-CoA molecule in every cycle to form acetyl-CoA.[24] Acetyl-CoA enters the citric acid cycle, where it undergoes an aldol condensation with oxaloacetate to form citric acid; citric acid then enters the tricarboxylic acid cycle (TCA), which harvests a very high energy yield per carbon in the original fatty acid.[25][26]

-Cancer: Numerous studies have found that the risk for cancer increases with high blood sugar, which makes sense, since cancer cells feed primarily on glucose. This includes cancers of the endometrium, pancreas, and colon and colorectal tumors. Tim Ferriss recently hosted a fantastic article by Peter Attia about this very issue, and how ketosis may indeed be a potential cancer cure.

The classic ketogenic diet is not a balanced diet and only contains tiny portions of fresh fruit and vegetables, fortified cereals, and calcium-rich foods. In particular, the B vitamins, calcium, and vitamin D must be artificially supplemented. This is achieved by taking two sugar-free supplements designed for the patient's age: a multivitamin with minerals and calcium with vitamin D.[18] A typical day of food for a child on a 4:1 ratio, 1,500 kcal (6,300 kJ) ketogenic diet comprises three small meals and three small snacks:[28]
“If you’re going to do keto, there’s a better and a worse way to do it,” says Yawitz. “Loading your plate with meats, and especially processed meats, may increase your risk for kidney stones and gout,” which is a painful type of arthritis. “High intake of animal proteins makes your urine more acidic and increases calcium and uric acid levels. This combination makes you more susceptible to kidney stones, while high uric acid can increase your risk for gout,” adds Yawitz.
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.
Hi Ben, I have a question about being in ketosis. So from what I understand, a serving of Keto os will keep you in ketosis for about 4-6 hours or so……my question is doesn’t your body have to be in constant ketosis in order to really experience the benefits of using the fat as fuel? Also, if someone is not following the Keto diet, what happens to the glucose they are still consuming if they are supposedly using ketones for energy? Also, do you see any benefit from using Keto os vs. Brain Octane? I ask because there is a significant difference in price. Thank you so much!!
The ketogenic diet has been studied in at least 14 rodent animal models of seizures. It is protective in many of these models and has a different protection profile than any known anticonvulsant. Conversely, fenofibrate, not used clinically as an antiepileptic, exhibits experimental anticonvulsant properties in adult rats comparable to the ketogenic diet.[58] This, together with studies showing its efficacy in patients who have failed to achieve seizure control on half a dozen drugs, suggests a unique mechanism of action.[56]

The benefits above are the most common ones. But there are others that are potentially even more surprising and – at least for some people – life changing. Did you know that a keto diet can help treat high blood pressure, may result in less acne, may help control migraine, might help with certain mental health issues and could have a few other potential benefits?

2) I'm currently using Ketocana and in that section you state "Similar to the BHB salts and MCT’s from the KETO//OS I discuss above, powdered forms of ketones are excellent if you don’t want to completely eliminate carbohydrates or fat or eat copious amounts of fats, but want to simultaneously maintain high levels of blood ketones." – How would eating copious amounts of fat be a negative? Wouldn't that help contribute to a ketogenic state?
“To achieve the relatively high rates of intake (up to 90 grams/hour) needed to optimize results in events lasting longer than three hours, athletes should practice consuming carbohydrates during training to develop an individual strategy, and should make use of sport foods and drinks containing carbohydrate combinations that will maximize absorption from the gut and minimize gastrointestinal disturbances.”
Once inside the mitochondrion, the dominant way that the bound fatty acids are used as fuel in cells is through β-oxidation, which cleaves two carbons off of the acyl-CoA molecule in every cycle to form acetyl-CoA.[24] Acetyl-CoA enters the citric acid cycle, where it undergoes an aldol condensation with oxaloacetate to form citric acid; citric acid then enters the tricarboxylic acid cycle (TCA), which harvests a very high energy yield per carbon in the original fatty acid.[25][26]
“When you start the keto diet, you lose sodium and other electrolytes in the urine due to reductions in insulin,” says Yawitz. “This is a major contributor to symptoms of keto flu.” So it’s important to replenish sodium through the diet, especially if you exercise or sweat a lot. “This can help ward off more serious side effects that are seen with long-term sodium deficiencies,” says Yawitz. These include lethargy and confusion — and in extreme cases, seizures, coma, and death, according to the Mayo Clinic.
Intermittent fasting is another way to achieve ketosis. This doesn’t suggest going days without food, but rather intermittent fasting. You can eat for eight hours and then fast for 16 hours, or eat a low-calorie diet for a few days (about 1,200 daily calories if you’re a woman and 1,500 daily calories if you’re a man). As you take in less food, your body uses more of its fat stores for fuel.
For example, a key component of safe and lasting fat loss is your capability to tap into your body’s own storage fat for energy. This access to fat cannot happen if your body is constantly drawing on carbohydrate reserves and blood glucose for energy. In the type of moderate- to high-carbohydrate diets you’ve learned are widely recommended by prevailing nutrition science, not only does the utilization of fat for energy become far less crucial (since you’re constantly dumping readily available sugar sources into your body), but your metabolism never becomes efficient at using fat. There is a growing body of evidence proving that a high-fat, low-carbohydrate diet results in faster and more permanent weight loss than a low-fat diet. Furthermore, appetite satiety and dietary satisfaction significantly improve with a high-fat, low-carbohydrate diet that includes moderate protein.
If you want to make some enemies very quickly, just jump on to social media and say "the keto diet stinks." Because there are certainly a number of people who swear by the keto diet. Some of them will even swear at you if you say anything bad about the diet. Supporters of the diet claim that the keto diet will help lose weight relatively quickly, clear your mind, make you feel better, and even clear up your acne, because you no longer are taking in carbohydrates that "cause inflammation." People who question the diet have raised concerns about whether maintaining such a high fat diet is effective and healthy in long run. After all, high fat diets could raise the risk of various chronic medical conditions such as heart disease and cancer.
I'm constantly on the lookout for low-carb diet and ketosis friendly option that allow hard charging athletes, especially athletes who have glycolytic, high-intensity demands during sport, to get a “slow bleed” of carbohydrate into their body. For example, “UCAN Superstarch” is one such option, but, unfortunately, I've found that many athletes and exercise enthusiasts tend to get gastric distress or excessive fermentation from that slow-release starch.
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]

Carbohydrates are necessary for the conversion of inactive thyroid hormone to active thyroid hormone, and if you’re on an extremely strict low carbohydrate diet, then you may actually be limiting this conversion. Your TSH is what tells your thyroid gland to “release more hormone,” so your TSH rises when your thyroid gland is underactive, or conversion of inactive to active thyroid hormone is inadequate. A high TSH means that the pituitary gland is releasing its hormone to try to get the thyroid to respond and produce more thyroid hormone. Because of inadequate carbohydrates, TSH will often elevate in a high-fat, low-carber – indicating potential for long-term thyroid and metabolic damage.


Signs of diabetic ketoacidosis include a high blood glucose level, a high ketone level, dehydration, frequent urination, nausea, difficulty breathing, and dry skin. If you have poorly managed type 1 or type 2 diabetes, test your blood glucose level regularly before and after meals, and make sure you check your ketone level whenever your blood sugar is higher than 240 milligrams per deciliter (mg/dL). (11)
Hello, I have a quick question. I’ve been on keto since March 2017. Already lost about 45 pounds, down to 140 at 5’7 and about 16.4% fat. I take a magnésium cap each morning to be sure I got enough and eat at least 1 serving of baby spinach a day with olive oil or fatty dressing that have no carbs. My last meal is always between 5 and 9 pm (mostly around 6) and I don’t eat back before 12pm the next day on week days and not before next dîner on week end. Fasting isn’t something new to me and when I read it help getting in ketosis I continued.

^ 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."
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