The ketogenic diet typically reduces carbohydrate intake to less than 50 grams per day — and calls for increased protein and fat intake, according to a review published in August 2013 in the European Journal of Clinical Nutrition. Roughly speaking, on keto you’ll get 70 to 80 percent of your calories from fat, about 20 percent from protein, and as little as 5 percent from carbs.
Here’s what we do know: The keto diet may be useful in treating symptoms of epilepsy, a seizure disorder. “The use of keto in treating epilepsy has the most evidence,” Angelone says. One study conducted by Johns Hopkins Medicine, for example, followed epileptic patients on the keto diet and found that 36 percent of them had a 50 percent reduction in seizures after three months on the diet, and 16 percent were seizure-free. However, experts aren't entirely sure why the keto diet has this affect, she adds.
Net carbs is simply total carbs minus fiber and non-digestible sugar alcohols, like erythritol. (This doesn’t apply to high glycemic sugar alcohols, like maltitol.) We don’t have to count fiber and certain sugar alcohols in net carbs, because they either don’t get broken down by our bodies, are not absorbed, or are absorbed but not metabolized. (Read more about sugar alcohols here.)
You indicate that exogenous ketones do not shut down the ability, of your body, to oxidize fat. Is that to say it does not have an effect on your body at all? My specific question is… does my body oxidize less fat, when supplementing with exogenous ketones? I think you indicate in your article that it could. I would expect it to, in that if I supplement then my body would not “need” to oxidize the fat to provide the energy.
“Studies have shown that the ability to stick to a diet is more important for long-term success than the type of diet that’s followed,” says Yawitz. “Keto is incredibly restrictive and is particularly tough for those who have frequent social engagements or are prone to carb cravings.” The Mediterranean diet allows you to eat carbs, like as many fruits and veggies as you want, along with whole grains. Not to mention, the Mediterranean diet has been linked to a number of other health benefits, including a lower risk of Alzheimer’s and Parkinson’s disease, certain types of cancer, and heart disease, according to the Mayo Clinic.
Around this time, Bernarr Macfadden, an American exponent of physical culture, popularised the use of fasting to restore health. His disciple, the osteopathic physician Dr. Hugh William Conklin of Battle Creek, Michigan, began to treat his epilepsy patients by recommending fasting. Conklin conjectured that epileptic seizures were caused when a toxin, secreted from the Peyer's patches in the intestines, was discharged into the bloodstream. He recommended a fast lasting 18 to 25 days to allow this toxin to dissipate. Conklin probably treated hundreds of epilepsy patients with his "water diet" and boasted of a 90% cure rate in children, falling to 50% in adults. Later analysis of Conklin's case records showed 20% of his patients achieved freedom from seizures and 50% had some improvement.[10]
Physicians of ancient Greece treated diseases, including epilepsy, by altering their patients' diet. An early treatise in the Hippocratic Corpus, On the Sacred Disease, covers the disease; it dates from c. 400 BC. Its author argued against the prevailing view that epilepsy was supernatural in origin and cure, and proposed that dietary therapy had a rational and physical basis.[Note 3] In the same collection, the author of Epidemics describes the case of a man whose epilepsy is cured as quickly as it had appeared, through complete abstinence of food and drink.[Note 4] The royal physician Erasistratus declared, "One inclining to epilepsy should be made to fast without mercy and be put on short rations."[Note 5] Galen believed an "attenuating diet"[Note 6] might afford a cure in mild cases and be helpful in others.[11]
Since originally publishing this article, I’ve been asked whether elevating blood ketones with exogenous sources could trigger a ketone-induced release of insulin that would theoretically reduce hepatic ketogenesis and perhaps slow fat mobilization. This makes sense since you are putting more energy into the system in general (from exogenous ketones), so there would be less need to draw off your own fat stores.

A systematic review in 2018 looked at 16 studies on the ketogenic diet in adults. It concluded that the treatment was becoming more popular for that group of patients, that the efficacy in adults was similar to children, the side effects relatively mild. However, many patients gave up with the diet, for various reasons, and the quality of evidence inferior to studies on children. Health issues include high levels of low-density lipoprotein, high total cholesterol, and weight loss.[24]

Lemons are also keto-friendly, so go ahead and add a spritz of lemon juice to your ice water. One typical lemon wedge has about 0.5  g of net carbohydrates and only 0.2 g of sugar. The fruit also offers  3.7 mg of vitamin C, which is 6.2 percent of the DV. Lemon water contains antioxidants that fight free radicals, and it also promotes healthy digestion, according to the Cleveland Clinic.

Remember how important it is to measure ketone blood levels accurately? Same goes for food tracking. A food tracking app, like MyFitnessPal, provides insight into macronutrient intake and thus the ability to tweak the diet to achieve ketosis. Tracking diet (inputs) and measuring ketones levels (outputs) delivers the best shot at optimizing the keto diet plan.
And it all culminated with me stepping into Dr. Jeff Volek’s world famous laboratory at University of Connecitut to subject myself to extensive blood testing, chunks of muscle removed from my legs, fat sucked out of my butt-cheeks, urine, stool and gut microbiome testing, oxygen and carbon dioxide testing and countless hours of treadmill running to discover what a full twelve months of eating a ketotic diet had actually done to my body.

The longer cholesterol circulates in your bloodstream, the higher the likelihood that it will dig its way into an endothelial wall and potentially contribute to atherosclerosis or plaque formation. This is why it’s so dangerous to eat a high-fat diet, but to also have your nightly dark chocolate bar, overdo it on the red wine, or have weekly “cheat days” with pizza, pasta, or sugar-laden ice cream.
^ 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.

To understand exogenous ketones, you should know that there are three types of ketones: beta-hydroxybutyrate (BHB), acetoacetate (ACA) and acetone, and all three are the normal by-products of fat breakdown by your body. In much the same way as glucose, ketones can be used by your tissues, especially your brain, diaphragm and heart and are actually a far more efficient fuel source than glucose.
It usually takes three to four days for your body to go into ketosis because you have to use up your body's stores of glucose, i.e., sugar first, Keatley says. Any major diet change can give you some, uh, issues, and Keatley says he often sees patients who complain of IBS-like symptoms and feeling wiped out at the beginning of the diet. (The tiredness happens because you have less access to carbs, which give you quick energy, he explains.)
I asked James Fell if he had some practical advice on sustainable dieting. “When it comes to weight loss,” he said, “the only thing that matters is caloric deficit. However, quality of diet affects quantity. A higher quality diet is more likely to be one that allows you to eat a lower quantity of calories and still be satisfied. That being said, there are many different ways to find a high-quality diet.”
Exogenous ketosis comes from an external source. Consuming exogenous ketones, like a ketone drink containing a ketone ester or a ketone salt, raises blood ketone levels. The body isn't producing ketones in this state, but still remains in ketosis from having ketones introduced from an outside source. However, the body isn't ketogenic–that specifically means the body is producing its own ketones.

"The keto diet is primarily used to help reduce the frequency of epileptic seizures in children. While it also has been tried for weight loss, only short-term results have been studied, and the results have been mixed. We don't know if it works in the long term, nor whether it's safe," warns registered dietitian Kathy McManus, director of the Department of Nutrition at Harvard-affiliated Brigham and Women's Hospital.


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]

Twenty elite ultra-marathoners and ironman distance triathletes performed a maximal graded exercise test and a 180 min submaximal run at 64% VO2max on a treadmill to determine metabolic responses. One group habitually consumed a traditional high-carbohydrate (HC: n = 10, %carbohydrate:protein:fat = 59:14:25) diet, and the other a low-carbohydrate (LC; n = 10, 10:19:70) diet for an average of 20 months (range 9 to 36 months).
I’m brand new to the Keto scene. Just started the diet on tuesday. There are so many supplements listed here. Is there a place to start? Like only starting with a couple? What about blood testing, do you recommend it it and how often and should i even be testing in the first month. Any help is greatly appreciated. You have the most informative articles I’ve been able to find.
Hi Ben, great article. I have been a keto-adapted athlete for over 2 years, all through nutrition (65/25/10). I have recently discovered UCAN, KetoOS and MAP Aminos. So, here’s my question: If I am going out for a 4-hour ride, and I want to fuel myself just on these supplements and my body’s natural fat stores, how and in what order should I take them? If I take them all together, will the aminos in the KetoOS interfere with MAP Aminos? Or should I just make a mix of the UCAN and KetoOS in 10oz of water and use it to wash back my 6 MAP tablets, 15-mins before my ride? Thanks for your advice!
For example, in trained people and athletes who eat a low-carbohydrate, high-fat diet (not to be confused with a low-carbohydrate, high-protein diet), a large amount of fat burning can take place at intensities well above 80 percent maximum oxygen utilization (VO2 max) – allowing for very-high-intensity or long efforts with low calorie intake and also allowing for use of fat fuel stores during long steady-state exercise, even at a relatively fast pace (so much for the “fat burning zone” giving you the best bang for your buck). With high-fat, low-carb intake, you can go hard and still burn tons of fat. In addition, this means that more carbohydrate stores will be available when you really need them, such as for an all-out, 100%, maximum effort.
3 years ago I was 500 pounds at my absolute worst. Went through a traumatic experience when I was 17 and afterwards the weight just seemed to add on over the years. I'd always been a big guy but it got really bad. Decided to start the keto diet after looking into healthier lifestyles and fast forward two years later (with intermittent fasting and gym training) I had lost 260 pounds. I kept under 1200 calories a day and the best feeling was not constantly being hungry. The last year has been more of a maintenance but with keto cycling.
Meat – like grass-fed selections – and fresh veggies are more expensive than most processed or fast foods. What you spend on Keto-friendly foods will vary with your choices of protein source and quality. You can select less-expensive, leaner cuts of meat and fatten them up with some oil. Buying less-exotic, in-season veggies will help keep you within budget.
Hi Stacey, I can’t give medical advice and definitely recommend following your doctor’s recommendations. You can ask him/her if low carb would be better suited for you. Also, you may want to double check with him/her if the kidney concern was related to high protein, because that is a common misconception about keto – it is not a high protein diet/lifestyle.

Net carbs is simply total carbs minus fiber and non-digestible sugar alcohols, like erythritol. (This doesn’t apply to high glycemic sugar alcohols, like maltitol.) We don’t have to count fiber and certain sugar alcohols in net carbs, because they either don’t get broken down by our bodies, are not absorbed, or are absorbed but not metabolized. (Read more about sugar alcohols here.)


Following the ketogenic diet and achieving ketosis may be beneficial if you’re living with type 2 diabetes and need to manage your symptoms. Limiting carbohydrate intake is crucial with type 2 diabetes because too many carbs can increase blood glucose levels, which can damage blood vessels and lead to vision problems, kidney problems, and nerve problems.
In the US especially, coconut oil and MCT oil manufacturers are legally allowed to claim that lauric acid is an MCT because chemists named it that way, even though it does not act like other true biological MCT oils. If you are relying on plain coconut oil or “MCT-labeled” oil to get enough useful MCTs, think again and check the label: odds are you’re getting very few of the potent, ketogenic shorter chain MCTs (also known as “C8” and “C10”), and instead getting mostly cheaper but ineffective lauric acid.
The ketogenic diet is not a benign, holistic, or natural treatment for epilepsy; as with any serious medical therapy, complications may result.[28] These are generally less severe and less frequent than with anticonvulsant medication or surgery.[28] Common but easily treatable short-term side effects include constipation, low-grade acidosis, and hypoglycaemia if an initial fast is undertaken. Raised levels of lipids in the blood affect up to 60% of children[38] and cholesterol levels may increase by around 30%.[28] This can be treated by changes to the fat content of the diet, such as from saturated fats towards polyunsaturated fats, and if persistent, by lowering the ketogenic ratio.[38] Supplements are necessary to counter the dietary deficiency of many micronutrients.[18]
“Suddenly and drastically reducing carbohydrates sets your body up for a double whammy of sorts,” says Yawitz. “The brain’s favorite fuel is glucose, which is most easily created from carbohydrates. In very-low-carb diets, the brain has to adjust to using ketones from digested fats for energy. To add to this discomfort, your kidneys release more electrolytes as insulin levels fall.” Additionally, your total body water decreases as carbohydrates become depleted on a keto diet, notes Clark. The result? What’s known as the keto flu, which could cause constipation, nausea, headache, fatigue, irritability, cramps, and other symptoms. Don’t fret, though: Many of these symptoms are short term and should last only a few days to weeks. Make sure to drink plenty of water to help your body cope with these symptoms. And call your doctor if symptoms — especially nausea — are prolonged, advises Yawitz.
A systematic review in 2018 looked at 16 studies on the ketogenic diet in adults. It concluded that the treatment was becoming more popular for that group of patients, that the efficacy in adults was similar to children, the side effects relatively mild. However, many patients gave up with the diet, for various reasons, and the quality of evidence inferior to studies on children. Health issues include high levels of low-density lipoprotein, high total cholesterol, and weight loss.[24]
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.
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?
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.
A systematic review in 2018 looked at 16 studies on the ketogenic diet in adults. It concluded that the treatment was becoming more popular for that group of patients, that the efficacy in adults was similar to children, the side effects relatively mild. However, many patients gave up with the diet, for various reasons, and the quality of evidence inferior to studies on children. Health issues include high levels of low-density lipoprotein, high total cholesterol, and weight loss.[24]

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?
Hi Ben great science & sound advice. May I share with the group? I’m 42, in australia, have been an alcoholic for 10 yrs. In April 2016 I gave up drinking & started living strictly ketogenic. In 3 months I dropped 25 kilos. I have cheated on weekends but I go through a fast of sorts on Mondays to get back into ketosis by Tues. I work afternoon / evenings so I wake at 10.30am take a pre workout drink with raspberry ketones & a splash of mct oil & all my vitamins as well. I then do weights for an hr then get ready to go to work. I take 2 800ml protein shakes consisting of 20 ml mct & 30grm amino enhanced protein. I work in warehousing so I walk anywhere between 10 km & 5 km a nite. I feel great all the time, thanks largely to your research & advice. If have any thoughts or opinions I’d love hear them.
“Certainly, the quality of fat counts,” says Yawitz. “There’s a big difference nutritionally between bacon and almonds. As much as possible, people set on the keto diet should emphasize plant-based, unsaturated fats like nuts, seeds, olive oil, and avocado, which have even been shown to protect the heart.” If you have high cholesterol or other risk factors for heart disease, you should speak with your doctor before beginning the keto diet. This is because the diet may — but doesn't have to — include large amounts of saturated fat. Some studies have shown increases in cholesterol and triglycerides in people following the diet, while other research reveals that the keto diet may actually decrease heart disease risk as well as saturated fat intake.
×