People seem to expect, based on fitness guru promises, that being in a state of ketosis feels like a cognition-enhancing, energy-stimulating power hour whereby your waist measurement is negatively correlated with your IQ. I usually just felt fatigued as hell if I tried to exercise, beating my body to death on an aged and grating stair climber at 6am. Then I went about the day eating random assortments of protein and fat, felt totally out of control at the sight of brownies in the office, overdid coffee to suppress my cravings and increase my metabolism, and went to bed feeling the dull ache of deprivation underneath my dieting high. And that was only the beginning.
This answer made me sad. Having lived in New York all of my life, I from a young age saw loved ones fall victim to spontaneous gluten intolerance and restaurants run to their rescue with accommodating menus.  This is why I get annoyed. What’s a dietary prescription for someone who wants to go to a dinner party and be able to eat a meal that was prepared for them? Keto is cultish not for its members’ radical commitment to a dietary restriction but for their lack of full participation in the outside world.
I'm at 240 now and actually weigh less than I did in high school. Have a decent amount of excess skin that skews my actual weight. Thankfully the government of Canada pays for plastic surgery in my case because it could lead to health problems in the future. Surgery is in about 8 or so months and I'm quite excited to start a completely new chapter of my life once it's done.
This article really bothers me in that if you do a few incorrect things with this diet, it will actually do more harm than a full carb diet. I have been in ketosis for a month or so but to what detriment? Based on the “ketosis darkside” list you highlighted, i could be doing any or all of these without realising. Could i share with you my meal plans and see if in your opinion they are beneficial and healthy or if im digging myself an early grave?
The ketogenic diet doesn’t put a cap on saturated fat or even trans fats. The latter are fats you should always avoid. Read ingredient labels and avoid any food with partially hydrogenated oils, aka trans fats. These fats heighten your LDL (“bad”) cholesterol levels and lower your HDL (“good”) cholesterol levels. They also raise your risk of heart disease and stroke, according to the American Heart Association.
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.
I talk about that quite a bit here :https://bengreenfieldfitness.com/2015/09/things-your-pee-can-tell-you-about-your-body/
If you’re following the keto diet, you will need protein, but you should limit your intake to about 20 percent of your total daily calories. (1) This is important because when you consume more protein than you need, your body converts the excess protein into carbs through a process called gluconeogenesis. This process pushes your body out of ketosis.
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.
If you have high triglycerides and low HDL, or you have any type of genetic issue that would cause you to have high sensitivity to saturated fats then the diet may not actually be for you. I think you should start by reading this: https://bengreenfieldfitness.com/article/nutritio… If you prefer a more direct, customized approach, 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.
Then one night, it all changed. I poured honey and water into a 42-ounce canister of Quaker oats and kept spooning because there was no other carb source in the house. Something strange had possessed me; I would later hear other binge eaters call this “blacking out,” or feeling such intense relief and disinhibition that you consume ridiculous quantities of food without fully realizing or experiencing it. At the time, I remember thinking something was very, very wrong, but the thing that was wrong was my lack of self-control and that I would be better -- keto!!! -- forevermore. And then I did it again a few nights later. I gained weight. I gave up on dieting eventually, but it took me years to reestablish a healthy relationship with food.

In fact, most folks have enough stored body fat to fuel aerobic activity for days and days without running out of energy. For example, a 150 pound dude at a hot, sexy and ripped at 8% body fat still carries 12 pounds of storage fat – which at 3500 calories per pound of fat can easily liberate 42,000 calories of useable fuel for exercise. You’ve got those same thousands of calories sitting around your waist, abs, hip, butt and thighs – just sitting there, waiting to be burnt.

Achieving ketosis is a pretty straightforward, but it can seem complicated and confusing with all of the information out there.4If you want to learn more about ketosis and the scientific process around it, you can visit a very in-depth discussion about on Dr. Peter Attia’s website. Here’s the bottom line on what you need to do, ordered in levels of importance:


Lots of apps and websites offer keto diet challenges—basically, a blueprint for the keto diet with a fixed starting and ending point (they typically last for a week to a month, though some may be longer). Speaking of apps, plenty of keto-centric ones are right at your fingertips (a.k.a., your smartphone), like the KetoDiet app, which can help you calculate your macros and track your keto diet effectively.


I am curious if someone takes any or too much MCT oil (5-10 tablespoons/day) or Exogenous Ketones will the liver slow/stall or shut off endogenous ketone production as you are providing the ketones exogenously and thereby you may NEED to supplement ketones to maintain ketone levels or you may suffer a short term ketone deficit while the liver adjusts to making them on its own again. A parallel I am thinking of is exogenous testosterone supplementation and the hypothalamus/endocrine system slowing/stopping endogenous testosterone production (seen in bodybuilders).
^ 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.
This is a wealth of information. My husband and I are starting the keto diet tomorrow and I knew nothing about it. When I sat down to look up information about it, I found this. Thank you! This is everything I need to know in one place. We are not as healthy as we’d like to be and I am optimistic this will help us obtain our goals, along with an exercise plan.
"Some people stop working with me because they're not going to be proven wrong. You’re dissing their religion," said Libby, a registered dietician who asked that her full name not be used because of the private hate messages she's received from the community.   “If there was a diet or a pill or something that really was this miracle diet weight-loss thing that lasted and was healthy for you, we wouldn't have all these different diets all the time, there wouldn't be health complications, there wouldn't be so much controversy about it and the first time that you'd be learning about it wouldn't be on a 3pm talk show."

I just discovered your site and have been thoroughly enjoying many of the articles and appreciate that you get so in depth in your explanations. I’m in my late 40’s and, while not an extreme endurance athlete, I am moderately active with 18-20 mile rides 3x a week as well as some boxing and body weight resistance (push up, pull up, etc) mixed in. I’ve generally been paleo and stick to quality macros for the most part (grass fed meats/dairy, organic veg and oils) and zero supplements. I recently started following keto (after reading this article) about 10 days ago and things seem good thus far. I do, however, want to avoid any of the negative side effects you mention and also not lose any lean muscle. I’m currently about 174 lbs, 5’8″ and about 19% bodyfat – I’m taking in about 95g protein, 130g fat and <20g net carbs. I'm eating all quality – wild salmon, grass fed beef, pastured eggs, coconut oil, Brain Octane and Grass fed butter in coffee, sardines, etc. With a smattering of organic veg, but it seems real easy to bust through the carb barrier. *I'M ALSO TAKING KETOCANA PRE-WORKOUT* and I notice this is keeping me going throughout a ride or the gym.
It’s also important to note there have been no long-term studies on the ketogenic diet, nor has there been research that details what may happen to the body if it’s in a constant state of ketosis itself. But given how the body needs carbs to function properly, diets that are based on fat burning may lead to nutritional deficiencies, and supplements and multivitamins are recommended because you’re cutting out entire food groups, warns Alyssa Rothschild, RDN, who is in private practice in New York City.
The original therapeutic diet for paediatric epilepsy provides just enough protein for body growth and repair, and sufficient calories[Note 1] to maintain the correct weight for age and height. The classic therapeutic ketogenic diet was developed for treatment of paediatric epilepsy in the 1920s and was widely used into the next decade, but its popularity waned with the introduction of effective anticonvulsant medications. This classic ketogenic diet contains a 4:1 ratio by weight of fat to combined protein and carbohydrate. This is achieved by excluding high-carbohydrate foods such as starchy fruits and vegetables, bread, pasta, grains, and sugar, while increasing the consumption of foods high in fat such as nuts, cream, and butter.[1] Most dietary fat is made of molecules called long-chain triglycerides (LCTs). However, medium-chain triglycerides (MCTs)—made from fatty acids with shorter carbon chains than LCTs—are more ketogenic. A variant of the classic diet known as the MCT ketogenic diet uses a form of coconut oil, which is rich in MCTs, to provide around half the calories. As less overall fat is needed in this variant of the diet, a greater proportion of carbohydrate and protein can be consumed, allowing a greater variety of food choices.[4][5]
I’ve been experimenting with MCT Oil Brain Octane. I have one questions. I’ve been eating about 20 – 25 gr. of carbs per day on a high fat, medium protein diet. I’m measuring ketones in the morning before taking the MCT and after. I’ve been taking btw. 1-2 tbsp of MCT Brain Octane with butter (Bulletproof coffee) – I measure again after 30 min., 1hr, 2 hrs. and don’t see a raise in my blood ketones. Anything I’m missing, would love to hear your thoughts, Ben. – Thx I’m measuring with Precision Xtra and Ketonix Red.
If I see a TSH above 2.0 or a trend towards higher values in someone who is testing repeatedly, I get worried – and prefer to see TSH at 0.5-2.0. Of course, this doesn’t mean that you begin to shove carbohydrates indiscriminately down the hatch. However, it means that your high-fat, low-carb diet should include thyroid supporting foods rich in iodine and selenium, such as sea vegetables and brazil nuts, and should also include carbohydrates timed properly, such as before, during or after workouts, when the carbohydrate is more likely to be utilized for energy and less likely to spike blood glucose levels.
^ Jump up to: a b c Clemente FJ, Cardona A, Inchley CE, Peter BM, Jacobs G, Pagani L, Lawson DJ, Antão T, Vicente M, Mitt M, DeGiorgio M, Faltyskova Z, Xue Y, Ayub Q, Szpak M, Mägi R, Eriksson A, Manica A, Raghavan M, Rasmussen M, Rasmussen S, Willerslev E, Vidal-Puig A, Tyler-Smith C, Villems R, Nielsen R, Metspalu M, Malyarchuk B, Derenko M, Kivisild T (October 2014). "A Selective Sweep on a Deleterious Mutation in CPT1A in Arctic Populations". American Journal of Human Genetics. 95 (5): 584–589. doi:10.1016/j.ajhg.2014.09.016. PMC 4225582. PMID 25449608.
Along with biomarker testing, subjective symptoms can provide an indication of your ketosis. Sometimes, early side effects of the diet result from carbohydrate withdrawal. This can be known as the "keto flu;" symptoms include nausea, fatigue, headache and dry mouth. They're short-term, typically lasting about a week or less. Keep in mind, however, that we are all different. Our bodies react in different ways. Some of us may experience these symptoms later than sooner, to a lesser extent, or not at all.

^ Jump up to: a b Sinclair, H. M. (1953). "The Diet of Canadian Indians and Eskimos" (PDF). Proceedings of the Nutrition Society. 12 (1): 69–82. doi:10.1079/PNS19530016. ISSN 0029-6651. It is, however, worth noting that according to the customary convention (Woodyatt, 1921 ; Shaffer, 1921) this diet is not ketogenic since the ratio of ketogenic(FA) to ketolytic (G) aliments is 1.09. Indeed, the content of fat would have to exactly double (324 g daily) to make the diet ketogenic (FA/G>1–5).


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.
On the ketogenic diet, carbohydrates are restricted and so cannot provide for all the metabolic needs of the body. Instead, fatty acids are used as the major source of fuel. These are used through fatty-acid oxidation in the cell's mitochondria (the energy-producing parts of the cell). Humans can convert some amino acids into glucose by a process called gluconeogenesis, but cannot do this by using fatty acids.[57] Since amino acids are needed to make proteins, which are essential for growth and repair of body tissues, these cannot be used only to produce glucose. This could pose a problem for the brain, since it is normally fuelled solely by glucose, and most fatty acids do not cross the blood–brain barrier. However, the liver can use long-chain fatty acids to synthesise the three ketone bodies β-hydroxybutyrate, acetoacetate and acetone. These ketone bodies enter the brain and partially substitute for blood glucose as a source of energy.[56]
On the keto diet, your body begins to shed fat, water and glycogen, and as this happens you lose key electrolytes, such as sodium, potassium and magnesium. When you're running low on these electrolytes, you might experience headaches or extreme fatigue. These losses are most pronounced during the first few weeks after you enter ketosis, so if you're going to start the keto diet it's best to plan ahead to make sure you get healthy amounts of these electrolytes — and other vitamins and minerals — either through supplements or a thoughtfully-designed meal plan.

Next, you need to ease yourself into this stuff. As I mentioned earlier, KETO//OS is blended with MCT’s, which can cause digestive distress if you’re not used to consuming them. This is due to the fact that your body has not yet adapted to the increased fats in your diet, and is less efficient at utilizing ketones as its fuel source. Once your body has adapted to MCT in the diet, the digestive distress will resolve.  But I recommend you start slowly with just about a half a serving a day, and over two weeks, build up to a full serving twice a day.
This article is excellent and I’ve actually read it a few times just to make sure I’m absorbing as much as possible. With that said can we talk a bit about protein? Why does it seem like protein is taking a back seat? What about the athlete who needs to maintain and/or increase muscle mass. I don’t want to make any assumptions and with all the research I’ve done along with personal testing into Keto it just seems to me that protein and its benefits are not a discussion point in this diet. Why?
On a ketogenic diet, your entire body switches its fuel supply to run mostly on fat, burning fat 24-7. When insulin levels become very low, fat burning can increase dramatically. It becomes easier to access your fat stores to burn them off. This is great if you’re trying to lose weight, but there are also other less obvious benefits, such as less hunger and a steady supply of energy. This may help keep you alert and focused.
And it’s not an easy diet to stick to, even in the short term. Fell pointed me to a series of articles he’d written after talking to scientists about low-carb diets. As a former track runner myself, I wasn’t surprised to hear him say that carb depletion is terrible for athletes, nor did it come as a shock to hear that fat isn’t necessarily going to make you feel “fuller for longer.”
“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.
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