CPAPtalk.com

Awesome to hear of a dietitian who doesn't dismiss it out of hand and sounds like she is willing to support you trying it.

Anytime, and let us know how it goes.

Update:

A change in diet lifestyle is a long-term proposition, so I'm not going to get too much into whether I feel any benefits or how well I'm sticking to it (over three days that's kind of meaningless). I will say that I've managed to adhere to the dietician's recommendations while dramatically reducing intake of carbohydrates. It's made me realize how much refined carbs I was eating, which was probably not good. I suspect I'm making up for it somewhat with proteins (also very satisfying). An example lunch has been a bowl of spinach with some sardines on it (dietician-approved). The spinach presumably has less than 5g of carbs while the sardines show carbs as zero. I wonder though if the proteins are not getting converted to glucose through gluconeogenesis. It's amazing how, when you reduce one bad thing (carbs), your body will quickly figure out how to achieve satiation through something else to take its place (proteins which can be converted to sugar).

I've been using the ketone tester, just to get some kind of baseline, and my usual values are at 0.2 mmol/L. I had one day when they were at 0.9 mmol/L, for reasons which are not totally clear (I gather that 0.2 is typical of someone who is *not* in ketosis). I've just been figuring out the test and getting a sense of the numbers, but will have to start documenting meals and numbers better. Let me stress that I am not necessarily trying to get into ketosis right now, just monitoring different parameters as I transition into the recommendations of the dietician with an emphasis on lowering carbs.

Those of you who have read my other posts know that I am a big-time numbers/physiology geek and I'm hoping that indulging this trait will make me more likely to engage in whatever diet I end up following.

Careful about "ODing' on protein... you don't just replace carbs with it (but rather, e.g. olive oil and other things) and it can lead to serious kidney problems. Moderation, balance, don't try and upend your system overnight!

Julie wrote:Careful about "ODing' on protein... you don't just replace carbs with it (but rather, e.g. olive oil and other things) and it can lead to serious kidney problems. Moderation, balance, don't try and upend your system overnight!

Hmm, not necessarily.

http://chriskresser.com/do-high-protein ... nd-cancer/

"After reviewing all of the published research on high-protein diets and kidney disease, the authors of this paper concluded that while high-protein diets can be harmful for those with kidney disease, they do not harm the kidneys in healthy individuals. Since that paper was published, new studies have tested the effects of high-protein diets on renal function in healthy individuals, and generally, their conclusions are the same. (7, 8, 9)"

http://ndt.oxfordjournals.org/content/20/3/657.full

"In summary, for individuals with normal renal function, the risks of high-protein weight loss diets are minimal and must be balanced against the real and established risk of continued obesity [11,12]."

49er

leptic wrote:Update:

A change in diet lifestyle is a long-term proposition, so I'm not going to get too much into whether I feel any benefits or how well I'm sticking to it (over three days that's kind of meaningless). I will say that I've managed to adhere to the dietician's recommendations while dramatically reducing intake of carbohydrates. It's made me realize how much refined carbs I was eating, which was probably not good. I suspect I'm making up for it somewhat with proteins (also very satisfying). An example lunch has been a bowl of spinach with some sardines on it (dietician-approved). The spinach presumably has less than 5g of carbs while the sardines show carbs as zero. I wonder though if the proteins are not getting converted to glucose through gluconeogenesis. It's amazing how, when you reduce one bad thing (carbs), your body will quickly figure out how to achieve satiation through something else to take its place (proteins which can be converted to sugar).

I've been using the ketone tester, just to get some kind of baseline, and my usual values are at 0.2 mmol/L. I had one day when they were at 0.9 mmol/L, for reasons which are not totally clear (I gather that 0.2 is typical of someone who is *not* in ketosis). I've just been figuring out the test and getting a sense of the numbers, but will have to start documenting meals and numbers better. Let me stress that I am not necessarily trying to get into ketosis right now, just monitoring different parameters as I transition into the recommendations of the dietician with an emphasis on lowering carbs.

Those of you who have read my other posts know that I am a big-time numbers/physiology geek and I'm hoping that indulging this trait will make me more likely to engage in whatever diet I end up following.

Hi Leptic,

I haven't used my meter for awhile which I really need to do. But I did notice that eating a can of sardines seemed to cause a higher spike than I expected which was about 20 points. Of course, if my blood sugar is low in general, that is not a horrible spike as long as it goes back down after two hours.

So to answer your question, I definitely think for some people a certain amount of protein can get converted to glucose. That is why on all diabetic boards and on this one, the common saying is eat to your meter.

49er

I asked earlier what references people would recommend if challenged by a dietician on the evidence behind the ketogenic diet. I probably should have clarified that this was more of a rhetorical question, and I doubt I would really start throwing papers at a healthcare professional to prove a point (hopefully this is a Julie-approved stance ). I was curious partly for myself regarding what evidence was actually driving this (there are indeed thousands of books, but the weight of a mass market book in scientific circles is rather low). Respectable Scientists are also supposed to dismiss/abhor anecdotal evidence so individual success stories also don't count .

Not having heard back much on this question, I tried the approach I would normally use as a working scientist and used various 'approved' search engines like PubMed, Google Scholar (yep), Scopus, ScienceDirect etc. There do indeed seem to be quite a few 'respectable' peer-reviewed scientific papers supporting the efficacy of low-carb (including ketogenic) diets as a means of wait loss and improving cholesterol/lipid profile.

This article, specifically on a ketogenic diet (studied in 120 volunteers), was published in the Annals of Internal Medicine in 2004, and has been cited 773 times according to Google Scholar (not including this post ). Lots of citations usually mean that a paper was influential and accepted by the scientific community, but it can also mean that the findings were controversial or that the authors have been very successful at self-citation (it's hard to pull the last one off 700 times though). I would encourage readers to go through the whole article, but quote the main conclusion here:

Compared with a low-fat diet, a low-carbohydrate diet program had better participant retention and greater weight loss. During active weight loss, serum triglyceride levels decreased more and high-density lipoprotein cholesterol level increased more with the low-carbohydrate diet than with the low-fat diet.

What's notable is that the above study is a randomized controlled trial, which the bare minimum standard for scientific evidence (with pills you can go further with things like double- and triple-blinding, but that's kind of hard with a diet). The authors note that "minor adverse effects" were more prevalent in the low-carb group, and the limitation that they can not dissociate the effect of the diet from nutritional supplements apparently taken by the group (this is the kind of thing that reviewers often insist on adding).

Another paper, published in NEJM in 2009, compared weight-loss diets with different compositions of fat, protein, and carbohydrates (not specifically ketogenic though). Their main finding, after studying 811 volunteers, was that

Reduced-calorie diets result in clinically meaningful weight loss regardless of which macronutrients they emphasize.

Overall, looking at PubMed searches like this revealed a huge amount of literature on drug-resistant childhood epilepsy, an indication for which ketogenic diet has been the standard-of-care for ages (childhood epilepsy is a horrible thing, but the link between ketosis and epilepsy is fascinating). There is also a healthy level of activity on ketogenic diets for treatment of obesity, and the recent literature has generally been supportive of their efficacy, like this one. The last article is notable because it is relatively recent and looks specifically at ketogenic diet in treatment of obesity. The journal (Endocrine) is published by Springer, which is a reputable mainstream publishing house. It does not say so in the abstract, but there were 53 volunteers enrolled in the study (not huge but probably sufficient given the effect size). The article has only been cited by 10 other publications (according to Google Scholar), which may be because it's not a huge sample size or other reasons (it's also only been two years).

You will see that the number of volunteers in a study correlates quite well with the 'impact factor' of the journal in which the findings are published (with NEMJ at the top). Bigger studies are generally considered more reliable, but there is a subtle issue that such very large scale studies are often restricted in their intervention and observation methods for economic and practical reasons.

There are articles looking at the impact of dietary supplements on the efficacy of ketogenic diets, and at least one study of potential interest for People Affected by Sleep Apnea, showing that a ketogenic diet (compared with a mediterranean diet) may lower physiological CO2 output. High levels of blood CO2 during breathing cessation are presumably a major physiological stressor in sleep apnea, so this might be relevant. I find it fascinating how all this is related - your body uses oxygen to burn sugar, and generates CO2 (and some water) in the process. Sleep apnea interrupts your supply of oxygen and ability to clear CO2, which surely plays a role in the secondary health effects. CO2 is also a key player in respiratory control (more-so than oxygen), so it's not hard to suspect that metabolism is central in this.

Disclaimer: this was not a particularly organized search, but it gives a sampling of what is out there. A more rigorous approach would be to identify a few key 'seminal' early articles and follow the citation trail to see if the conclusions have stood the tests of time and scrutiny. It's also good to work backward, looking at the most recent articles on a topic and evaluate their methods, what advances the article purports to make, and where it's published (a low-end 'vanity publishing' journal where scientists can 'pay to publish' vs. a competitive high-impact journal that will have 'leading experts' in its reviewer pool).

Julie wrote:Careful about "ODing' on protein... you don't just replace carbs with it (but rather, e.g. olive oil and other things) and it can lead to serious kidney problems. Moderation, balance, don't try and upend your system overnight!

Up until now, I have been ODing on just about everything...

Julie wrote:Careful about "ODing' on protein... you don't just replace carbs with it (but rather, e.g. olive oil and other things) and it can lead to serious kidney problems. Moderation, balance, don't try and upend your system overnight!

I'm also hoping that a can of sardines with lunch won't constitute ODing!

Seriously though, your words about moderation, balance, and long-term vision are very wise and well taken.

http://www.amazon.com/Principia-Ketogen ... =8-1-fkmr0

Lots of mouse studies, though. And it's rapidly becoming outdated.

Protein in a keto/LCHF diet should remain relatively moderate. It is NOT a high protein diet. It's a high fat diet. Up your heathy real fat for satiety.

Blood ketone readings over 0.5 indicate you're in ketosis. You don't need high numbers to indicate success. Numbers tend to be higher at night than in the morning. As long as blood glucose remains low, I've seen people who go as high as 6.0 be very comfortable in ketosis, usually during a prolonged fast.

leptic wrote: . . . Another paper, published in NEJM in 2009, compared weight-loss diets with different compositions of fat, protein, and carbohydrates (not specifically ketogenic though). Their main finding, after studying 811 volunteers, was that

Reduced-calorie diets result in clinically meaningful weight loss regardless of which macronutrients they emphasize.

It is well proven scientifically that anything that reduces calories can work short-term.

But no dietary weight-loss approach has been proven scientifically to have success at improving overall health long-term.

The rest is mostly noise.

It is the equivalent of "this is obviously a marker for certain health problems; so, hey, I know, let's find what temporarily helps that marker!"

jnk... wrote:But no dietary weight-loss approach has been proven scientifically to have success at improving overall health long-term.

Hence the emergence of mega-studies like this one... not targeted specifically at diet, but launched in recognition that the usual small cohort, short-term study is indeed limited in its ability to predict long-term health impact. The CLSA is supposed to be a vehicle for sub-studies on groups drawn the huge overall cohort, which will hopefully include diet, sleep, and other lifestyle factors.

One often overlooked benefit relying on a high percentage of fat for your diet
is it reduces the oxygen you need. It seems you use less oxygen to get a calorie
from burning fat than you do burning carbs. I forget the figure but it was either 20
or 25% less oxygen to get that calorie from fat. I believe that sometimes people
with advanced COPD are then put on very high fat diets because of this. I guess the
Dr's then think the help reducing there need for oxygen then may out weigh the
evils of a high fat diet.

Not a study of ketogenic diets per say (it's the fantasy idea of a Mediterranean "diet", but that's a whole other topic), but a diet with a relatively high percentage of fat (compared to conventional advice): http://www.thelancet.com/journals/landi ... 7/fulltext

A long-term intervention with an unrestricted-calorie, high-vegetable-fat Mediterranean diet was associated with decreases in bodyweight and less gain in central adiposity compared with a control diet. These results lend support to advice not restricting intake of healthy fats for bodyweight maintenance.

The "long-term" was 5 years.

Janknitz wrote: Blood ketone readings over 0.5 indicate you're in ketosis. You don't need high numbers to indicate success. Numbers tend to be higher at night than in the morning. As long as blood glucose remains low, I've seen people who go as high as 6.0 be very comfortable in ketosis, usually during a prolonged fast.

I was up to 0.6 mmol/L yesterday afternoon, so perhaps something is going on. I have felt my cravings for carbs diminish, and have not had some of the extreme lethargy I used to get after a carb-heavy meal. I really think that was killing my motivation to exercise, which was in turn affecting the quality of my sleep (immediate weight loss is less of a priority).

My wife got back from a week-long business trip last night, and my kids really wanted nachos for dinner (chips, cheese, salsa, tomatoes, cucumbers). Normally I feel compelled to inhale a vast quantity of these, but was able to have a small portion that was more cheese than nachos (after dutifully reading the label on the nachos bag and seeing the carbs). Was able to avoid the sugar-laden salsa, which I normally love, without really much effort. Some/much of this may be psychological, but I'll take that!