Ketosis in a Nutshell – Part 6, A Hungry Man

weighing-scales

(When all else fails, read the instructions.)

A hungry man finds a haven – what was it?

He was a very hungry man.

That’s what worried him. That, and the weight gain.

“he had a pathological fear of hunger” *

“I was literally afraid of dieting. I was afraid of being hungry.”**

A bean pole in high school, when he graduated he “was 6 feet tall and weighed only 135 pounds”. But that didn’t last. “At college I became the biggest eater on campus.”

He went to medical school and then came a residency in cardiology. “I had the reputation of being the biggest chow-hound in the hospital.”  He gained weight over the years, but his mind failed to register this, as he still had a mental image of himself as slim.  Perhaps he also partly didn’t want to recognize it because he was so afraid of the hunger that is a routine part of low-calorie dieting.

It took seeing a photo of himself for Dr. Atkins to recognize the fact that he had become  “a fat man“, as he put it – in the typically kind way people have when they speak to themselves about their weight.  The year was 1963, and Dr. Atkins embarked on a quest.  Not willing to face the hunger of the usual calorie restricted approach, he “was looking for “The Hungry Man’s Diet.””. He hit the medical research to look for another way. Kids – this meant picking up and reading ink-on-paper “medical journals” that sat on shelves in the “library” of the hospital.

What was it that he found?

And why should we think about this now, 40 years later?

Why should we care what Dr. Atkins was reading or thinking in 1963, almost 50 years ago?  Why should it matter now what he put in his 1972 book?  After all, he published a number of books after that one. No-one should be held to what their medical ideas were 40 years ago – new information and experiences bring rapid changes in all areas of medicine.

Well, it’s not like things are going so good on the weight loss topic right now. I thought I’d have a read of his 1972 book. I have a paperback version of that book, published in 1973 by Bantam. What I read in that book grabbed my attention. For example, “The result of fifty years of prescribing a so-called “balanced diet” for patients who actually were suffering from a metabolic imbalance is a raging epidemic of over-weight.” (p.2).  If you look at a chart of changes in BMI over the past decades, you will see that 1972 is now considered to be “the good old days” when it comes to the battle of the bulge.

When all else fails, read the instructions.

The vast majority of people do very well with following a low carb, high fat eating plan that is well thought-out and explained – such as can be found in The Art and Science of Low Carbohydrate Living. For most people, there is no need to make it more complex. Some people follow the instructions closely, and yet don’t find that their weight reduces into the normal range. Different people need different solutions. Can we get some ideas by looking back to the original version of the most famous low carb plan.

What was at the core of Dr. Atkins’ “Revolution”?

(Terminology – will open in new window)

There is a common perception to think about the Atkins Diet in terms of the protein and the salads and the low carbs. What does his first book tell us about what he was thinking?

In his book “Dr. Atkins Diet Revolution”, published in 1972, he describes the research findings and line of thinking that led him towards his approach to obesity. I looked into some of the research he discusses and found it such a fascinating insight into the medical thinking of the time that I have included a discussion of that below. I think if you click on the links to the abstracts and papers you will enjoy the read.

In summary, researchers had found that hunger was suppressed after 1-2 days of total fasting, and that this reduction in hunger was correlated to an increase in blood levels of ketones. Other researchers found that this also happened on a very low carbohydrate diet – within 1-2 days hunger was “absent” (maybe a bit of an overstatement) and blood ketone levels had risen over that time period  Diet trials with patients eating to appetite of unlimited protein foods and fats, with very limited carbohydrates, showed weight loss with lack of hunger.

Dr. Atkins was ready to try this approach for himself. Dr. Walter Lyons Bloom had developed a 3-day food plan to test the low-carb theory. People ate eggs, bacon, meat and salad. Dr. Bloom reported that they developed the same lack of hunger as was noted when patients underwent total fasting. Dr. Atkins tried it and had the result he was after. He was loosing weight and not hungry. Now, what about the ketones? In the publications he had read, when ketones were tested they used blood ketone testing.  Dr. Atkins bought urine ketone test strips at a local pharmacy. He tested his urine and there was the purple color on the test strip showing that he was in ketosis.

Slowly he developed this 3-day sketch of a diet plan into a workable long-term plan that enabled a gradual return to a higher level of carbohydrate intake, according to individual tolerance.

** The above information and quotes are from chapter 3 of the 1972 book “Dr. Atkins’ Diet Revolution”, entitled “How I Arrived at This Diet Revolution”.

Let’s look at chapter 2, entitled “The Diet Revolution: It Will Change Your Life”.

“This is the diet revolution: the new chemical situation in which ketones are being thrown off – and so are those unwanted pounds, all without hunger.”

“I have arrived at the conclusion that ketosis is a state devoutly to be desired, because while you are in this happy state … your fat is being burned off with the maximum efficiency and minimum deprivation (since in ketosis your hunger disappears!).”

“Here’s how this diet is significantly different. During the first week on this diet, you cut your intake of carbohydrates down to what is biologically zero. This creates a unique chemical situation in the body, the one most favourable to the fastest possible burning of your body’s stored fat. Ketones are excreted, and hunger disappears.” (Here he was comparing his program to several diet programs of the day that reduced carbohydrates, but not to less than 60 grams per day, thus not creating significant ketosis in most people.)

“We must maintain this chemical situation if you’re to continue to lose without hunger.”

Let’s look at chapter 5, entitled “If You’re Always Fat, Chances are You’re “Allergic” to Carbohydrates”.

“It is not a true allergy as we doctors know it, but it is a sensitivity to carbohydrates in the diet, which results in an overproduction of insulin (hyperinsulinism).”

“For millions who suffer the endless physical and emotional miseries of being fat, it is a tragedy that so few authorities understand most overweight for what it is – a disordered carbohydrate metabolism, which affects some people and not others, that is quite apart from the amount of food, or calories, consumed.”

The rest of this chapter focuses on the many effects of a disordered carbohydrate metabolism, including high insulin, diabetes and aspects of what we now think of as metabolic syndrome.

You can read most of chapter 1 online. The first 6 pages of the 8 and a bit pages of chapter one are included in an Amazon preview. This preview is labeled as from 1981, but it is identical to the Bantam 1973 paperback version of the 1972 hard cover version that I have. Since this is on the Amazon site, this review might not still be there when you try the link. LINK

Carb Control for Health and Appetite, Ketosis for Hunger Control in Weight Loss?

As far as I can see from a careful reading of his book and from the papers he cites as influences, in 1972 Dr. Atkins saw his contribution as having been the development of a program that (1) targeted ketosis as a sustainable tool in weight loss, (2) made ketosis workable long term to last throughout the weight loss period and (3) offered a workable transition to a highly individualised flexible controlled carb lifestyle for long term health benefits. He refers to the fact that a number of popular books advocating low carb intake had been published by 1972, but none of them (according to his report, I don’t have copies of these books) presented ketosis as a unique aid to weight loss – by reducing appetite and allowing maximum fat burning – much less presenting a workable long-term way to achieve this. He stated that his goal was to find a way to lose weight without being tormented by hunger and he found it – ketosis.  He also understood the need to avoid the many harms from carbohydrate intolerance – by a lifelong practice of keeping carb intake within one’s personal tolerance limits.

In the 1972 book, Dr. Atkins advocated deliberately maintaining a state of nutritional ketosis until the last phase of the weight loss period. When the person is close to their goal weight, they were advised to slow the rate of weight loss by further increasing their carb intake – and thus the ketones in the urine would slowly fade away. He noted that for some people ketones don’t show in the urine, in which case they will have to rely on symptoms – are they hungry, having cravings, not feeling as well or no longer loosing weight/inches.

From that point on (once the weight was at goal), he emphasized that it was vital to maintain health and weight control by continuing to carefully control carb intake. He advised that it was fundamental to long term success to make the effort to adjust one’s carb intake – both amount and specific foods chosen – according to one’s individual tolerance. It was important to carefully monitor oneself over time for weight regain or signs of carb intolerance. This tolerance level might also change over time.

Regarding carbohydrate intake (amount and food sources) over the long term: “You’ll end up with a diet that’s as personal to you as a pair of contact lenses.” (p. 29)

During weight loss: “You will find which shade of purple correlates best with your own feeling, and this, for you, is the ideal.” (p. 130)

What about the role of protein intake when aiming for ketosis?

Unfortunately, there is no reference that I can find in the 1972 book to the potential role of moderate or high protein intake as something that might interfere with the development of ketosis. Dr. Atkins writes that protein can be metabolised to glucose, but he doesn’t mention trying a lower protein intake (1) as a means to achieve ketosis for those whose urine test strips don’t turn colour or (2) as a means to enable weight loss for those whose weight loss is slow or stalled.

In the 2002 edition of his book “Dr. Atkins New Diet Revolution”, there is brief mention of the fact that too much protein can interfere with weight loss, but there is no focus on that.  For example, in Chapter 15 “Engine Stalled? How to Get Past a Plateau”, among the many suggestions given, there is no discussion of considering or lowering protein intake.

Chapter 20 “Metabolic Resistance: Causes and Solutions” is described this way: “This chapter is about extreme difficulty in losing weight … “. Adjusting protein intake is not discussed directly as a strategy, except in terms of the Fat Fast, which is one of many topics in this chapter. If the Fat Fast is successful and the Induction program is not, then Dr. Atkins suggests trying to adapt the Fat Fast, such as “simply follow the concept of increasing the ratio of fat to protein”.

In Chapter 17 “Lifetime Maintenance”, there is a statement and answer section.  One is “4. Misconception: You can eat any food so long as you do not exceed 20 grams of carbs a day.” The answer “Reality: If you eat junk foods or other nutrient-deficient carbohydrate foods instead of vegetables and other nutrient dense foods, you will miss most of the benefits I write about …”. No mention of amount of protein foods.

Yet, in the same section is Misconception #9, to which part of the answer is “Moreover, excess protein converts to glucose and can keep fat from becoming the primary fuel.” Brief statements similar to this are in 3 – 4 other places in the book, but never elaborated on. It seems from all this that Dr. Atkins dealt with this problem in the office, but that it just somehow didn’t make it into the book in a very clear way or with a description of how to tackle it.

Still, the vast majority of people can benefit greatly from a low carb diet, in the manner that Dr. Atkins taught, without needing to deliberately limit their protein intake – as long as they are following his instruction to eat as much food as required to feel satisfied, but no more.

Is there any difference in how to get into ketosis?

There are some differences here that are interesting to think about.

The first week is far more strict than what is now considered to be the “Induction” eating plan. The only carb sources allowed other than the small amounts present in flesh food, eggs and small amounts in such things as bullion, gelatin and spices were:

  1. hard, aged cheese up to 4 ounces a day
  2. heavy cream up to 4 teaspoons per day
  3. juice of one lemon or lime per day
  4. “two small salads a day (each less than one cupful, loosely packed) made only of leafy greens, celery, or cucumbers and radishes. …  Or else a sour pickle in place of a salad.”

In the second week, 5 – 8 grams of carbs are added to the daily diet, but this was the “old” way of counting the carbs, before Dr Atkins switched to subtracting the fiber content from the carb total, so serving sizes of vegetables were much smaller than now. That is, the serving amount of a vegetable that was said to give 5 grams of carbohydrate would actually contain much less “usable” carbs (sugars or starch) than 5 grams, because some of what was counted as “carbs” was fiber. Depending on what a person was choosing to eat, many would still be under the 20 grams of carbs (total carbs minus fiber) considered Induction Level now.

Thus, there would be a tendency for people to move into ketosis both faster and deeper in the first week, compared to the instructions from 1992 on, when “Dr. Atkins’ New Diet Revolution” was first published – which moved to a two week Induction period with less strict carb reduction. They would move into “week two” at a higher level of ketones than now and likely progress further into ketosis while following the “week two” instructions. For many people, depending on individual food choices, they would not be up to the carb intake of what is now the “Induction” phase until they reached week 3 and added another 5 – 8 grams of total carbs (total = fiber included in the count).

In fact, although it was called “week 2″, Dr. Atkins did not want to see anyone progress from the first week’s eating instructions until they were clearly displaying the symptoms and changes that suggested they were well into a state of ketosis. As well, of course, he expected to see the urine ketone test strips turn purple. “Now it is time to evaluate whether or not you may progress to level two.”  His criteria for moving up a stage in carb intake included such things as lack of hunger, correction of evening/night eating, sense of having more energy and losing weight/inches.

The week one instructions also could be used as recovery strategy to get back on track if one had any symptoms that too many carbs had been consumed – such as hunger or cravings. Again, these instructions would promote a faster move into a deeper level of ketosis that the later “Induction Phase” instructions.

Interestingly, when you look at the “Induction Phase” instructions in the 2002 edition of “Dr. Atkins’ New Diet Revolution” the daily intake of vegetables is limited to “approximately three cups – loosely packed – of salad, or two cups of salad plus one cup of other vegetables (see list …)”. Some higher carb foods, such as limited amounts of sour cream, avocado and tomato are allowed, but Dr. Atkins denotes these as “Special Category” foods and notes that they might need to be avoided if progress is not good. I think many people think of Induction Phase as including a lot more vegetables than that.

In Sum

Dr. Atkins’ 1972 book is the first presentation of a sustainable dietary program that deliberately overtly includes nutritional ketosis in a central role. In Dr. Atkins’ original presentation of his concepts, there was a dual emphasis on ketosis as the key to hunger control and fat mobilization during weight loss; along with carb control to individual tolerance as a key to health, to abstinence from trigger foods and to weight maintenance over time. There was an emphasis on a rapid transition into ketosis. There was an emphasis on targeting the degree of ketosis according to whether it met the duel main criteria of suppressed appetite with a sense of well-being. There was a strong emphasis on sustaining such a symptom-targeted state of ketosis until the weight loss phase was almost completed.

The vast majority of people do well with the instructions in low carb or low carb high fat (LCHF) currently recommended by responsible authors and bloggers. Still, there are those whose health goals are not achieved by following such instructions.  It may be worth considering aspects of other versions a low carb high fat approach. This has been a look back at history to review the roots of the current low carb lifestyle.

I found my journey into this book fascinating. This discussion focused on the ketosis aspect of it, but if you have or can access a copy of this book and you have a strong interest in the topic of low carb nutrition, you might enjoy reading this book as much as I have.

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I’m doing my best to understand Dr. Atkins’ practice and thinking based on his books.  Because of a realistic need to keep things somewhat simplified in a book, there is likely a lot of Dr. Atkins’ insights and accumulated wisdom that didn’t appear in any of his books. There are a number of clinicians who have direct experience with Dr. Atkins who could provide much better history and insight – for example, Jacqueline A. Eberstein R.N. and Eric Westman M.D. It is Dr. Atkins’ books, however, that created the public perception about his work. Much of what is now called “Atkins” is a mis-interpretation or mis-representation of what people read, or half-remembered that they read, or thought they heard from a friend about what the friend read – - in his books.

* written by Jacqueline A. Eberstein, R.N., in her “Chapter 20: Thirty Years of Clinical Practice with Dr. Robert Atkins: Knowledge Gained”, included in the book “The Art and Science of Low Carbohydrate Living” by Jeff S. Volek, Ph.D., R.D. and Stephen D. Phinney, M.D., Ph.D.

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More on the research that Dr. Atkins credited with informing his thinking about hunger, diet and obesity:

One line of thinking was to mimic starvation.

(Note that this is similar to how the ketogenic diet for epilepsy was developed, where they were trying as closely as possible to mimic starvation without the person starving.)

Fortunately, Dr. Atkins would not have had to look very far to find his first clues. In the July 28, 1962 edition of The Journal of The American Medical Association (JAMA, one of the most prominent medical journals in the world) there was a paper by Dr. Garfield Duncan and others.

“Correction and Control of Intractable Obesity: Practical Application of Intermittent Periods of Fasting” JAMA  1962;181(4):309312   abstract

They reported on their results with periods of total fasting (“non-nutritious liquids” and vitamins) lasting 4 to 14 days (in hospital) with 50 patients, and subsequent follow-up management.  The weight loss results were very good, but what caught Dr. Atkins’ attention was the fact that these patients did not experience undue hunger after the first 1-2 days.

“Anorexia was the rule after the first day of fasting” … that was interesting! (anorexia means lack of appetite)

Furthermore, “and paralleled the degree of hyperketonemia”.  In other words, hunger went down as blood ketone levels rose. It took about a day for the blood ketones to rise much.

Even more, “A sense of well-being was associated with the fast.”

Dr. Duncan was a very prominent diabetes specialist, with a strong interest in weight loss.(I see there is a Garfield Duncan Building at Pennsylvania Hospital). I found this interesting report about the work of Dr. Duncan – note that this report has to be viewed with some caution, as it apparently quotes a Reader’s Digest article from 1968, rather than a medical paper.

The other thing that really strikes me about this is that here was Dr. Duncan, a noted diabetes specialist, completely unafraid of the ketosis induced by the fasting. It is very regrettable that this correct understanding of diet-induced ketosis did not become common knowledge in the medical community.

There was also this article published in 1963 in The Transactions of The American Clinical and Climatological Association, 1963; 74:121-129.  LINK to full text.

“Intermittent Fasts in the Correction and Control of Intractable Obesity”

This paper reports Dr. Duncan’s experiences with now 107 “obese diabetic and non-diabetic patients”.  It is fascinating to read the full article and I encourage you to do so.  One interesting tid bit is that “in three cases of previously resistant psoriasis this disorder subsided during the reduction program”. (We keep re-inventing the wheel.)

The patients would be hospitalized for the initial fasting period, then sent home on a limited calorie diet (that was not low in carbohydrates).  At home, they would fast for 1-2 days at intervals, generally one day per week (patient examples given). Exercise was not permitted on fasting days.  Some information on the longer term is given, but it is limited in detail. Forty percent of patients regained to previous weight or more, 43% maintained their weight and 17% were still loosing at last follow-up, which was at 1 – 32 months. (This is not nearly an adequate look at the medium and long term outcomes.)

His conclusions include “The anorexia during total abstinence from food is associated with, and is believed to be due to, the hyperketonemia provoked by the fast.”.

Keep scrolling down the paper to the discussion among a number of doctors at the end, including other illuminating comments by Dr. Duncan, such as “once patients have been subjected to a total fast, invariably they prefer it to low calorie diets” – commenting on the one day weekly fasting program. They also discuss initial water weight loss and water weight regain with return to eating.

(That people preferred one day a week fasting to the daily miseries of a chronic low calorie diet hardly constitutes much of an advertisement for intermittent fasting.  It is more a comment on the limited options these people felt they had. Also, we don’t know if it would have been as useful without the initial period of strong ketosis. As well, truly long term results are not given. Finally, some people might move towards dis-ordered eating and restrict/rebound eating patterns in response to intermittent fasting.)

Dr. Duncan followed these papers with a number of other publications on this topic, until he retired in 1969, including looking at hazards of fasting and the use of allopurinol for high uric acid levels induced by fasting.

Dr Atkins also credits an influence from the work of Kekwick and Pawan, who published a number of papers on obesity in the 1950s and up to 1969.  What he understood from their work was that ketones also appeared in the urine after 48 hours without carbohydrates in the diet – thus you could have ketosis without fasting -  and the ketones were again associated with loss of hunger. The loss of hunger was interpreted to be because the body was satisfying its hunger by burning body fat stores.

Thus, to some degree you could mimic the effects of fasting by strictly limiting carbohydrates.

Another line of thinking was that there can be a defect in how the body utilized carbs.

He also looked at the work of Dr. Alfred W. Pennington, who felt that the core issue was a defect in the ability of people who were obese to metabolize carbohydrates. Dr. Pennington was targeting reduction of carbohydrates and interpreting the resulting ketosis as evidence that removing the effect of the abnormal carbohydrate metabolism now freed the body to use fat as fuel. Ketosis as a hunger-suppressed state was not his goal, it was a sign that he was at his goal – sufficient reduction in the adverse effect of carbs. He was not concerned that protein intake would have any impact on ketosis.

J Clin Nutr. 1953 Jul-Aug;1(5):343-8.

Treatment of obesity with calorically unrestricted diets.

PENNINGTON AW.  PMID:13096572   LINK to full text. (takes a while to load)
I think most of what is discussed and speculated in this paper is not of current interest because the concepts are so dated and the discussion seems somewhat contradictory.  However, lots of times people find things that are useful in practice, even though they might not know how it works or their theories may be off the mark. Interestingly, Dr. Pennington emphasises that one of the important instructions for the diet is to eat sufficiently fatty meat. “The proper proportion is 3 parts of lean to one part of fat.”  If the meat is not fatty enough, then one is to buy extra fat (such as the fat from around the kidneys – apparently one could readily purchase that at the time) and cook it and have it with the meat. This work received attention because it was, at least in the short term, effective.
There were attempts to replicate this work by other researchers, including two in Europe, published in French and Swedish. There was also a report published in Canada.
“Experiences with the Pennington Diet in the Management of Obesity” by Wilfred Leith, published in The Canadian Medical Association Journal 1961 June 24; 84(25): 1411-1414.  LINK to full text.
They describe the Pennington diet as having the dual goals of (1) carbohydrates under 50 grams a day and (2) a strong focus on bulky foods. Having a lot of bulk in the meal was thought (and still is a topic) to be a major contributor to satiety. (I think this is actually a highly individual thing.)  However, I think this is their own spin on it, reflecting this team’s interest in bulk as a means to satiety. Dr. Pennington’s 1953 paper reveals no evidence of a focus on bulky foods (also his target was under 60 grams of carbs).

Why did they do the study? “The treatment of the obese patient has followed a stereotyped pattern for the past 20 years. Prescribing a simple low caloric diet and sympathetic handling of the patient, the usual method, had not been a rewarding form of clinical treatment. Usually, the patient was disturbed by a continual gnawing sense of hunger.”  Saying it like it is – not always a striking feature in medical writing today.

Ketosis in a Nutshell – Part 2, Crazy Little Things

Oh, just an alternate fuel system  – no biggie …..

Got Ketones?

When you break down fats for energy production and you do this while there is a low glucose supply, you wind up with a little bit left at the end, which is then metabolized to acetoacetate. Acetoacetate can be metabolized to acetone or beta-hydroxybutyrate. All three of these molecules then circulate in the blood stream.  They are referred to as ketones, although technically beta-hydroxybutyrate does not fit the definition for ketones. Functionally, beta-hydroxybutyrate acts like a ketone in that it can readily be metabolized back to acetoacetate, thus acting as sort of a transit or storage form of ketones.

English: Synthesis of ketone bodies from acety...

English: Synthesis of ketone bodies from acetyl-CoA Deutsch: Synthese von sog. Ketonkörpern aus Acetyl-CoA (Photo credit: Wikipedia)

In chemistry, there are many, many molecules that are of the type classed as ketones.  When we refer to “ketones” in your body, we are specifically meaning the three molecules I have named above.  The term “ketone bodies” has been used as a catch-all phrase for these specific three molecules (one of which is a ketone supplier, rather than a ketone itself).

When it comes to the ketones present in the blood stream, these have been made by the liver predominantly, although the kidneys are a minor source.  We are learning more about ketone metabolism. For example, recent research suggests that cells in the brain that metabolically support the neurons can make ketones and can scale up the production of ketones when needed.  This would be for local use – we don’t think of these as leaving the brain to supply ketones in the blood stream.

How Ketones Function in Your Body  (terminology list at bottom of Part 1)

  • They can be burned as a fuel.  There are three fuel types the body can use – glucose, fatty acids and ketones.  The neurons in the brain can only burn glucose and ketones. The brain uses a lot of energy every day. During fasting or starvation, the body would have to break down a lot of protein to supply the brain with enough glucose for all its energy needs.  In prolonged fasting or starvation, the muscles would be consumed at a quick rate.  Persistence of muscle strength and survival are much longer because ketones can replace a lot of the glucose the brain needs. Ketones can not supply all your needs for glucose. Glucose must be at least at low normal levels in the blood at all times and is produced by the liver as needed (unless metabolic or liver function is very impaired by illness, drugs or genetic metabolic illness).
  • This allows the dietary glucose supply to be low  – in fact, there is no need for glucose from the diet. (Sugars and starches are the source for glucose in the diet. Starch is pure glucose.) This has profound implications for the management of all forms of diabetes and pre-diabetes and impaired insulin function. It also has profound implications in sweet addiction and food addiction.  The body requires much less insulin than when glucose is being absorbed from food as a major part of the diet.
  • Ketones aren’t glucose – they don’t need the glucose transport system, and so are not hindered by insulin resistance. For example, this has implications in Alzheimer’s Disease as research is exploring the theory that part of what is going on in Alzheimer’s Disease is “Type 3 diabetes” – that is, insulin resistance of the brain and abnormal insulin metabolism in the brain.
  • Ketones are burned for energy differently than glucose.  Also, they produce less stress in the mitochondria and cells.  This means there is potential for ketones to be useful to cells that are damaged or stressed or with abnormal metabolism.
  • Burning ketones for energy requires less oxygen to produce a given amount of energy than when burning glucose.  This means ketones have the potential for benefit in situations of low oxygen supply – such as injured tissue or stroke.
  • Ketones are being studied for potential direct effects besides as a fuel – such as increasing adenosine production and thereby suppressing abnormal excitability in the brain.

The topic is much more involved than this list suggests. See links below to very detailed review articles.

The Whole is More Than the Sum of its Parts

In sustained dietary ketosis:

  • there are elevated levels of ketones circulating in the blood (and some research suggests extra ketones being made in the brain)
  • there are the effects noted above on fuel supply and handling
  • the ketone fuel supply is steady and ample
  • the blood glucose level is steady and normal or low normal, with low requirements for insulin

Therefore, when evaluating any apparent benefits observed with dietary ketosis, it is difficult to tease out which of the possible mechanisms (or which combinations of possible mechanisms) are at play. (Again, if you are interested, check out the links below.)

Note that if ketones are elevated because ketones are directly given (this is being developed for medical application) or because of a high intake of medium chain triglycerides, there is not necessarily a low carbohydrate intake from food, and so the effects on blood glucose levels and insulin requirements would not be the same.

Sustained Ketosis Brings A Reduction in Appetite

Something about being in sustained dietary ketosis results in a reduction in appetite, which develops over the first days or, in some cases, weeks. This is not an abolition of appetite (although this can uncommonly occur at the beginning – thought possibly due to a too rapid shift into the starvation/ketosis adaptation). The appetite is not killed, just lessened.

This is a general human reaction to sustained dietary ketosis.  You don’t have to have any trouble handling carbohydrates to have this response.  It doesn’t matter whether you are slim, overweight or obese.  It happens in the young and the old.  It doesn’t matter if you have insulin resistance or not.  Of course, there is variability between people in this, as in all things.  Keep in mind – some people do not seem to be metabolically suited to do well with ketosis and some people should avoid ketosis for various medical reasons.  There are people with rare genetic metabolic problems who should definitely avoid being in ketosis (and this condition may not be obvious, even into young adulthood).

We have little insight into this phenomenon, but it has long been noted. We don’t know what it is about dietary ketosis that causes this. It is likely a combination of more than one of the mechanisms above.  I am not aware of any research attempt to really study this phenomenon.  This seems a little surprising to me given the massive research effort to find usable medications that will lessen appetite.  Of course, such a medication would be a financial block-buster, so there is money available for that research.  Does the degree of appetite reduction relate only to the blood ketone level?  Does it relate more to the degree of stability of the blood sugar?  Do variations in liver glucose output matter – for example, liver insulin resistance or glucose output precipitated by a stress hormone spike?  Can we learn to manage this phenomenon to best take advantage of it?  It would be nice if we had the knowledge to be able to enter this state of reduced appetite with the least costs in terms of effort, dietary limitations, risks, etc.

The reduction in appetite does bring its own risks:

  • it is easy to mistake feeling adequately fed with being adequately nourished
  • it is easy to become lazy about food and meal preparation – eating from a narrow range of foods and not taking the time to prepare vegetables, salads, etc.
  • relying on ketosis for appetite control and using this as a way to avoid learning about and dealing with other factors affecting your appetite/satiety balance, such as stress and sleep.  Good health is always best served by a broad approach to wellness – over-relying on any one health strategy can lead to neglect of other aspects of your health.
  • acting as a source of confusion when people slip in and out of a ketotic state

A Tipping Point in The Balance of Actual and Potential Benefits Versus Actual and Perceived Practical Usability?

The implications of an alternate fuel system are enormous. The major block hindering progress towards more people deriving more benefit from this potential is the actual and perceived difficulties in people learning and following the diet and finding the ketogenic diet worthwhile over time.

The benefits side of the balance going up …

The very successful use of ketogenic diets in epilepsy, as well as the insistence of  patients and patient’s parents that they value this option despite the difficulties involved, has helped spur a growing amount of research into the therapeutic use of ketones and ketosis.  Findings from other fields, such as the theories of so-called “Type 3 diabetes” as a possible factor in Alzheimer’s disease, have also increased the realization of the actual and potential benefits of ketogenic diets.

There is an increased drive to re-consider the benefits of nutritional ketosis given:

  • the now very large numbers of people
  • who have medical problems for which there are presently limited or poor treatment options ( e.g. obesity, blood sugar control, Alzheimer’s, etc.)
  • who might find benefit from nutritional ketosis
  • or who at least might benefit in the near future from further research into the subject area.

How about the practical usability side of the balance?

To be continued ….. Part 3

*** Also, please see addendum published today at the bottom of Part 1

Ketosis in a Nutshell – Part 1, What’s Up? (itsthesatiety.com)

Related articles

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Some recent publications:  (links fixed)

(1) very interesting recent paper, full text available, plus active links to almost all of the 192 papers in the list of references (“KD” = ketogenic diet):

“Rekindled interest in metabolic and dietary therapies for brain disorders complements new insight into their mechanisms and broader implications. Here we describe the emerging relationship between a KD and adenosine as a way to reset brain metabolism and neuronal activity and disrupt a cycle of dysfunction. We also provide an overview of the effects of a KD on cognition and recent data on the effects of a KD on pain, and explore the relative time course quantified among hallmark metabolic changes, altered neuron function and altered animal behavior assessed after diet administration. We predict continued applications of metabolic therapies in treating dysfunction including and beyond the nervous system.”

The nervous system and metabolic dysregulation: emerging evidence converges on ketogenic diet therapy.

Ruskin DN, Masino SA.  Front Neurosci. 2012;6:33. Epub 2012 Mar 26.

PMID: 22470316  Free PMC Article

(2) extensive review article, full text available, extremely detailed on scientific investigation of metabolic effects of ketones and ketosis

The neuroprotective properties of calorie restriction, the ketogenic diet, and ketone bodies.

Maalouf M, Rho JM, Mattson MP.  Brain Res Rev. 2009 Mar;59(2):293-315.  Review.

PMID: 18845187   Free PMC Article

(3) review article, this links to abstract, but full text does not seem to be open access

“The large categories of disease for which ketones may have therapeutic effects are:(1)diseases of substrate insufficiency or insulin resistance,(2)diseases resulting from free radical damage,(3)disease resulting from hypoxia.”

The therapeutic implications of ketone bodies: the effects of ketone bodies in pathological conditions: ketosis, ketogenic diet, redox states, insulin resistance, and mitochondrial metabolism.

Veech RL.

Prostaglandins Leukot Essent Fatty Acids. 2004 Mar;70(3):309-19. Review.

PMID: 14769489

(4) interesting discussion, which challenges some current widely-held concepts in biochemistry.  It would be interesting to see a rebuttal by a biochem prof. Full text available.

Metabolic effects of the very-low-carbohydrate diets: misunderstood “villains” of human metabolism.

Manninen AH.   J Int Soc Sports Nutr. 2004 Dec 31;1(2):7-11.

PMID: 18500949   Free PMC Article

(5) A recent line of research suggests a cautionary attitude towards ketosis as evidence suggests some (or many, or most ??) tumors can be fueled by ketones produced by fibroblasts closely associated to the tumor cells. This is just the most recent of a number of papers regarding this line of research.  Of note, they are not researching the effect of ketones in the blood stream – this research is specifically and only about ketones produced in fibroblasts right by the malignant cells (part of the tumor mass itself).  Also, this work does not negate the line of research suggesting some cancers may be unable to metabolize ketones and may show reduced growth when ketones are high and glucose is low normal (especially malignant gliomas) – see below.

Ketone body utilization drives tumor growth and metastasis.

Martinez-Outschoorn UE, Lin Z, Whitaker-Menezes D, Howell A, Sotgia F, Lisanti MP.

Cell Cycle. 2012 Sep 19;11(21). [Epub ahead of print]  PMID: 22992619

(6) ketogenic diet being investigated for potential benefit in brain cancer (Note: there must always be glucose in the blood.  No glucose in the blood equals rapid death.  It is not possible to starve tumors by cutting off the glucose supply in the blood. The blood glucose can be brought down to low-normal, minimally fluctuating levels.)

Is the restricted ketogenic diet a viable alternative to the standard of care for managing malignant brain cancer?

Seyfried TN, Marsh J, Shelton LM, Huysentruyt LC, Mukherjee P.

Epilepsy Res. 2012 Jul;100(3):310-26.  PMID: 21885251

Ketosis in a Nutshell – Part 1, What’s Up?

Macadamia integrifolia (Macadamia Nut) - culti...

- - an inside joke – macadamia nuts are popular among those seeking ketosis.

We Newly Have Practical Access to a Potentially Major Health Intervention

CLUNK  - – Click, click … whirrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr …….

The recent adoption of home testing of blood ketones as a tool in the use of nutritional ketosis is like a missing gear being dropped into place. Many streams of knowledge and progress are brought together in a new and newly workable way.

Ketosis and Nutritional Ketosis – What is this?

You can learn to eat in a way that causes you to burn a lot of fat while burning low amounts of glucose. In the process, your liver will produce ketones, these will travel in your blood stream (ketosis) and be burned for energy. You have altered your “nutrition” to be in a state of “ketosis” – thus the term “nutritional ketosis”. This is also referred to as eating a “ketogenic diet”. When you do this over time, you gradually become more adapted to functioning in this state. This is called being “keto-adapted”.

This is all entirely different from diabetic ketoacidosis, which is a very serious medical emergency that can develop very rapidly and is potentially fatal. Ketoacidosis is precipitated by dehydration in the context of insulin deficiency. A person who is not deficient in insulin function will not develop ketoacidosis.

It seems to be talked about a lot recently. Why the buzz?

This is an eating strategy that can act as powerfully as a medication.

This eating strategy may improve your sense of well-being and physical performance.

It may be useful in many more situations, involving many more people, than we thought.

It has now become much more practical to use as a long-term choice than we thought.

Known and Potential Uses:

(1) Medical

When considering what we know of nutritional ketosis, plus what new insights and research suggest, nutritional ketosis has or may have a substantial role to play in:

  • blood sugar control
  • management of metabolic syndrome
  • visceral fat control
  • obesity
  • appetite control
  • epilepsy, in both children and adults
  • Alzheimer’s Disease and some other neurological conditions
  • and what others unknown?

(2) General Well-Being

Besides the above, many people who have become keto-adapted report that they just feel a lot better over-all. Many report improved energy levels, mood or mental clarity.

(3) High Performance

Beyond that, being in nutritional ketosis can mean improved physical performance, particularly in endurance activities. Competitive athletes are making use of this.

Great – But is it Usable? Is it Practical Long Term?

The key to unlocking the great potential for benefit is that nutritional ketosis must be a realistic, practical option for long-term use. This has been the major block. Why consider it as an option for people to use if it just seems to be much more of a burden that a help?  Why do a lot of research about something that won’t be used?  It must be worthwhile – the benefits must be worth the “costs” in effort, limitations, risks, etc.

The key criticism of ketogenic diets and thus of the use of nutritional ketosis as a health tool or medical treatment has been that they are “too difficult” and not worthwhile over time.

(1) Poor testing options mean we have not been able to accurately assess either long term benefits or long term practicality.

A “ketone” is a type of molecule, not just one molecule. However, the tests measure just one of the types of ketone molecules that the body produces when in ketosis.

Until recently, the only test for ketosis that could be used day-to-day at home was urine test strips. Blood ketone testing could be done at a medical lab, but this was too expensive and awkward for routine use. The trouble is, urine test strips are not very useful for monitoring the level of ketosis once a person has become adapted over weeks to being in ketosis.

The reason ketone test strips were developed and marketed is so people with diabetes can test themselves for ketones and so have early warning if they are headed for ketoacidosis and need to seek urgent medical attention. The urine strips test for a molecule called acetoacetate, which shows up in the urine right away when someone is just going into ketosis or has been in ketosis a short time. For diabetics, this works very well and is a cheap, convenient test (at least, for those people with diabetes who are not chronically in low-level ketosis from choosing to eat in a way to be in nutritional ketosis).

When people eat in a way to develop ketosis, the body adapts to this. Part of this adaptation is that the metabolism of the various ketone molecules changes. The level of acetoacetate molecules go down, so that, for example, the person can be in a low level of ketosis and yet this might not show on a urine test strip.  In this situation, use of blood ketone testing provides much better information.  Blood ketone home monitors test for a different ketone molecule called beta-hydroxybutyrate.

Blood ketone home monitors have been available for a while, but have been little known outside of the field of diabetes and even then, not widely used. Their potential role as a tool in the use of nutritional ketosis has only recently arisen as a topic.

The particular trigger for this was the publication in April 2012 of the influential book The Art and Science of Low Carbohydrate Performance by Jeff S. Volek, PhD, RD and Stephen D. Phinney, MD, PhD. Subsequently, awareness and interest in the topic has surged in the wake of the reports by Jimmy Moore of the very widely followed blog Livin” La Vida Low Carb, detailing of his personal experiences with using blood ketone testing. Jimmy Moore’s n=1 Experiments: Nutritional Ketosis Day 91-120

(To be fair, I should acknowledge that the first mention I saw of blood ketone testing meters was on Dr. Peter Attia’s site in March 2012.)

(2) Any medical treatment that cannot be well monitored or adapted to the individual over time will always appear less effective and more burdensome than it truly need be.

It may be that the benefits of nutritional ketosis have been masked by lack of ability to monitor or target the degree of ketosis properly for individual tolerance and benefit. That is, perhaps the lack of good testing options has meant that the way ketosis has been used has made that it appear less effective than it really can be and, at the same time, more difficult or burdensome to live with than need be.

Deliberately eating in a way to cause ketosis has basically been used in two ways:

  • as a medical treatment for epilepsy, in which extremely strict diets were used
  • as part of a low carbohydrate weight control plan (Atkins Diet), of which ketosis is a major tenant. The lack of ability to accurately test to see if a person stays in ketosis over time, and the degree of ketosis, has likely been a source of confusion and inconsistency – likely major factors in the degree of variability in people’s responses and how people do over time.

(3) Blood ketone testing brings individuals a better chance of finding lasting benefit.

Consider a person who has benefits from being in sustained ketosis (being keto-adapted). If that person is going in and out of ketosis or having wide fluctuations in their degree of ketosis, those benefits will come and go in confusing, unpredictable ways.  In this case they may well find that the efforts and costs (things they give up, changes in their life, any side-effects and risks, etc.) are not worthwhile over time. If they choose to abandon their efforts to be in ketosis, they then get zero benefits.

If they can use home testing of whether they are in ketosis and the degree of ketosis, they can use this to more accurately perceive any benefits. With more effort and time they can get a reasonable idea of what level of ketosis is associated with what degree of benefit. In terms of the costs, they will have realized what eating patterns or other factors are required for them to be able to be in ketosis or at certain levels of ketosis. From experience, that person can begin to form a judgement of what the balance of benefit versus cost is for them. There is a better chance that they may find at least some level of benefit that they are able to enjoy long term because they are able to choose a level of costs that they personally find worthwhile.

The benefits a person can notice for themselves will often be only part of the story.  Assessment by their physician, possibly including lab tests and other investigations, is a necessary part of considering what the benefits have been.  Even then, some of the benefits may be difficult to evaluate and some may be slow to develop and only evident over years.

Similarly, it is dangerous and unwise to assume that the harms and burdens a person notices themselves are the whole picture. Again, assessment by a physician, possibly including lab tests and other investigations, is a necessary part of considering what harms there have been and what the ongoing risks are. Even then, there may be unrecognized or hidden harms that do not become evident until some years later

(4) Blood ketone testing will open up progress in understanding and research.

People can communicate with each other and with their health providers much more effectively about their experiences with nutritional ketosis.  Researchers can target new questions and new areas of potential benefit.

For example, many research studies have been done to evaluate the benefits of low carbohydrate diets. Yet, none of them have used monitoring of blood ketone levels as a tool to evaluate the presence or depth or variability of nutritional ketosis despite the fact that it is one of the key proposed beneficial mechanisms of low carbohydrate programs. (** see addendum below for correction)  Again, consider the fact that if a person is unknowingly moving in and out of ketosis they are likely to find this very disruptive and un-satisfactory, which could well lead to abandonment of the intended eating plan and a perception that it is not worthwhile.

So, There is Promise  – What are the Risks or Concerns?

We are in the early stages of understanding about nutritional ketosis and how this might be useful for general well-being or medical purposes. The potential for benefit seems to be large.

What we already know for sure is that some people’s bodies seem to adapt well to ketosis and some people’s do not. There are some people for whom nutritional ketosis is not suitable.

We need to learn much more about possible side-effects and potential for harm, especially long-term. We do already know about some side-effects and harms that can develop that we need to be cautious about – for example dehydration, exaggerated  medication effects and serious problems with sodium and potassium. There is considerable potential for harm from un-recognized long-term deficiencies of essential nutrients, as feeling “full” does not in any way mean that one is well “filled” with the essential vitamins and minerals.

As with everything else in health and medicine, there is wide variation between people in the benefits and the harms that any individual may personally experience.

The trade-offs and cautions and risks (an incomplete list):

  • this requires following a very specific eating pattern, and this needs to be learned
  • that eating pattern needs to be consistent over time, with little use of “breaks” or “holidays” from the eating pattern
  • it takes a while for your body to adapt to using ketones for fuel and, until then, you may have side-effects and feel tired or unwell
  • you will be more susceptible to dehydration, to low blood sugar, and to potentially serious problems with the “electrolytes” sodium, potassium, calcium and magnesium. If you don’t take the time and effort to learn about these things,and are not prepared to be disciplined about them, do not consider proceeding.  Beyond that, there are medical conditions and medications and herbal (and other) therapies that can mean you are even more susceptible to these problems, and these must be considered. Nutritional ketosis is not appropriate in all situations.
  • there are certain situations or medical conditions that would mean that you should not use nutritional ketosis (or should do so only with knowledgable professional help). One particularly critical consideration is that there are certain medications that may need to be changed or doses adjusted before starting and possibly at frequent intervals in the first days, weeks and months.
  • you will need to put some time and effort into learning how to not harm yourself with poor nutrition while eating this way. Feeling full does not in any way mean that your full nutrient requirements are being met. Poor nutrition can be hidden and not produce warning signals that are obvious or easily understood. Our ability to monitor with lab tests how well you are stocked with the many essential vitamins and minerals is remarkably poor.
  • children and pregnant women require special consideration beyond the scope of this article.

This is an incomplete list. Even 5 years from now, it will not be possible for anyone to produce a complete list. The full risks of harm from nutritional ketosis, especially over a prolonged time, are not known. Have caution.

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** Addendum Sep 29/12  – Touched by an Angel – Thank-you to Jenny Ruhl for gently pointing out my carelessness in this paragraph.  What I wrote was not correct as stated and what I wrote did not match very closely what I was trying to express.  I’ll take another stab at it.  – Many studies have been done to investigate the usefulness of the “low carb diet” approach to weight loss. These fall into two types. One type of study is basic research – “what can we demonstrate happens when we carefully do “x””.  “How does the body respond under these circumstances?” They are done on relatively small numbers of people and under close supervision.

The other type of study is designed to see how useful the intervention “x” proves to be in larger numbers of people in something closer to a real-world situation  – this intervention “x” may have certain effects on the body, but is it useful under practical circumstances?  When you offer this to people, do the benefits play out as expected?  As part of this – do people continue with the intervention or do they abandon it for one reason or another?  As it turns out, generally in these larger studies there are many people who do not follow the low carb eating plan as instructed for very long into the study period.

These results form a major justification for the continued claim and perception that “low carb diets” may be theoretically useful but fail in the long run, and they fail specifically because people find they are not able to stay with the diet plan.

“Low carbohydrate diets” are not necessarily ketogenic diets, although they may be, and this causes confusion and error.  From what I recall, the emphasis in these larger studies is on the “low carb intake” rather than on the “dietary ketosis” itself.  If you go back to Dr. Atkins’ 1972 book, he strongly emphasized the critical role of ketosis, with low carb being the means to that end. Then you have to ask yourself, what is being tested?  I think the question has been muddied, which, if so, would certainly compromise the usefulness of the research results.  In research, it is all about the question.  If people aren’t taught that ketosis is the central target, how to be in ketosis and then adequately supported in understanding, trouble-shooting and individualizing their lifestyle/health/diet program to optimize their ability to attain and maintain ketosis, then what is being tested may be any manner of other useful questions about various degrees of limitation of carbs in the diet, but the results of the study will have no meaning towards questions about dietary ketosis.  Having people do urine ketone testing may or may not represent this level of focus and support.

For example, the description of the low carb diet used in the 2008 study published in the New England Journal of Medicine, in which they did use urine ketone testing:

“This low-carb, non-calorie restricted diet aimed to provide 20g/day of carbohydrates during the induction phase (first 2 months), and returned to this level of severe carb restriction after each religious holiday. At other times participants were instructed to increase carbs gradually up to maximum of 120g/day to maintain the weight loss. Total calories, protein and fat intake from any source (except industrial -trans fats) were not limited.”

This is a brief summary of the “low carb diet” used in this study:

Weight loss with a low-carbohydrate, Mediterranean, or low-fat diet.

Shai I, Schwarzfuchs D, Henkin Y, Shahar DR, Witkow S, Greenberg I, Golan R, Fraser D, Bolotin A, Vardi H, Tangi-Rozental O, Zuk-Ramot R, Sarusi B, Brickner D, Schwartz Z, Sheiner E, Marko R, Katorza E, Thiery J, Fiedler GM, Blüher M, Stumvoll M, Stampfer MJ; Dietary Intervention Randomized Controlled Trial (DIRECT) Group.

N Engl J Med. 2008 Jul 17;359(3):229-41. Erratum in: N Engl J Med. 2009 Dec 31;361(27):2681.

PMID: 18635428  Free Article

They were testing a more liberal version of the “Atkins diet”, which is a perfectly valid thing to do.  There are many aspects of the whole ball of wax referred to loosely as “low carb” that are in need of study.  They were not trying to study ketosis and they did not claim to have learned anything about the value or effects of sustained ketosis.  In the full text, they only report the urine ketone level at baseline (pre-diet) and at 24 months.  I don’t see any mention of urine ketone testing at any other time or of the participants using at-home urine ketone testing as a way to monitor whether they are in ketosis or as a way to prompt any changes in what they are doing.  Of course, a part of the reason for this may be the awareness of the imprecision of urine ketone testing in milder states of ketosis once a period of adaptation to ketosis has passed.

Given that they are reporting on their results with a “low carbohydrate diet”, even though they did not study ketosis, the results may be mis-interpreted as applying to sustained ketosis.

If people are unknowingly and inconsistently moving in and out of ketosis, it would be expected that they would experience the appearance and disappearance of both welcome effects and unwelcome side-effects.  It would be expected, in that circumstance, for weight and appetite and energy levels to fluctuate widely.  This could be expected to be very discouraging and result in many people abandoning the diet.  The sudden jump in hunger when moving out of ketosis would often lead to even greater food intake, putting the person firmly out of ketosis.  Carbohydrate craving in this circumstance can simply be a sign of moving out of ketosis, but, without proper education and awareness about ketosis, is likely to always be interpreted as an emotional desire for carbs or as “missing them” too much (which can also happen).

I hope that the increase generally in research and interest related to ketosis, along with the availability of home blood ketone meters, will lead to :

  • a clearer framing of the question and study design, taking the above into consideration – are they studying ketosis or not
  • if they are NOT studying ketosis, a recognition of the importance of a study design that does not ignore the possible confounding factor of ketosis
  • if they are proposing to be studying ketosis, or Dr. Atkins’ original claims, a recognition that teaching the study participants a “low carb diet” or “very low carb diet” and having it “sort of” followed is not any longer an acceptable proxy for studying a “ketogenic diet”

*******************************************

To be continued …. Part 2

Important Note: This article is written to promote discussion. It is not intended to be medical advice. It is not intended to promote the use of a ketogenic diet or nutritional ketosis by any specific individual. Any person who would like to consider the use of a ketogenic diet or nutritional ketosis should first seek the advice of their personal physician. This article is an overview and does not provide enough information for anyone to use for clinical decision-making.

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

The Terms

“Ketosis”  means there are “ketones” in your blood. People have at least a very small amount of ketones in their blood all the time. Generally, the word “ketosis” is only used when the ketones are more than just the usual very low day-to-day background level.

“Ketones”  are a type of molecule you produce in your metabolism. They are produced in the liver during the breakdown of fat molecules. These ketones do not show up in the blood at more than trace levels unless there is a lot of fat being broken down in the presence of low supplies of glucose. Insulin stops the production of more than trace amounts of ketones, and insulin levels are higher with increasing amounts of glucose.  Ketones are a valuable fuel molecule and an essential part of our metabolism. They are not directly harmful in any way except if they reach extremely high levels, which can only happen in diabetes (see “ketoacidosis”).

Ketones can be used for fuel by almost all the organs and cells of the body. One of the especially important things about them is that they are the only fuel besides glucose that the brain can use. The brain uses ketones for a fuel very readily, but ketones can not be used in all the ways that the brain uses glucose, so there is always a need for an adequate, normal level of blood glucose (some other cells also need glucose, such as the retina and the red blood cells).

“Ketone bodies”  – In chemistry, there are many, many molecules that are of the type classed as ketones.  When we refer to “ketones” in your body, by common usage we are specifically meaning three molecules named acetoacetate, acetone and beta-hydroxybutyrate.  Technically beta-hydroxybutyrate does not fit the definition for ketones. Functionally, beta-hydroxybutyrate acts like a ketone in that it can readily be metabolized back to acetoacetate, thus acting as sort of a transit or storage form of ketones. The term “ketone bodies” is useful in that it has been used as a catch-all phrase to refer to these specific three molecules (one of which is a ketone supplier, rather than a ketone itself). (Note: this description amended Sep 29/12)

“Ketoacidosis”  is a very serious, potentially fatal condition that can occur in people with diabetes. Having insulin in the blood to stops ketones from going very high, so people who produce enough of their own insulin will not develop very high ketone levels no matter how they change their food intake. Even people in starvation do not get ketoacidosis (unless they are diabetic).

“Nutritional ketosis” or “dietary ketosis” means that, because of what you have or haven’t eaten, your body is making more of the type of molecule called “ketones”. This distinguishes ketosis caused by reasons outside the body from ketosis produced by abnormal function of the body (deficiency of insulin).

“Depth of ketosis”  or “degree of ketosis” refers to how much the level of ketones in the blood rises.  You are “deeper in ketosis” as your blood level rises higher.

“Keto-adaptation”  is a term coined by researcher Dr. Stephen Phinney M.D. to refer to the fact that it takes some weeks and up to 2-3 months for a person’s body to fully adapt to functioning in a state of nutritional ketosis. That is, to become adapted to using fats and ketones as the predominant fuel, instead of the usual situation, where glucose is used as the predominant fuel. Part of keto-adaptation is that there is a normal, steady  blood level of glucose, with the glucose coming mostly from sources within the body, rather than coming mostly from the digestion and absorption of glucose from food.