Kurt G. Harris MD

PāNu means paleonutrition. The "paleo" here signifies "old" and not necessarily paleolithic. The PāNu approach to nutrition is grounded on clinical medicine and basic sciences disciplined by knowledge of evolutionary biology and paleoanthropology. The best evidence from multiple disciplines supports eating a pastoral (animal-based) diet rather than a grain-based agricultural one, while avoiding what I call the neolithic agents of disease - wheat, excess fructose and excess linoleic acid.

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Tuesday
Aug252009

On zero carbs, can you make your glucose from fat?

 

 

Prompted by another reader question:

You can indeed make some glucose from the glycerol backbone of triglycerides, but there is not enough lipolysis occurring to avoid needing amino acids as the principal feedstock of gluconeogenesis if you get no dietary carbohydrate. With no carbs in your diet, you will need some excess protein. If you ate only 10% of calories as protein, and 0 % carbs, you will start wasting muscle.

Again. the glucose level in your blood is a requirement even if there is not a dietary requirement for glucose. Neurons can shift metabolism partly to ketone bodies but still need glucose and red blood cells need glucose.

My bias is that we did not evolve to have "tight" macronutrient requirements. Unless your metabolism has been broken by the SAD (sometimes it is) you should not have to measure or weigh anything.

My staples are pastured eggs, cream and pastured butter. rare cooked red meat or seafood a few times a week, and occasional vegetables for flavor and variety. My caloric intake varies up to 20% some days, and I do not weigh or measure anything. My weight has been steady in a + or -1 lb range for at least 18 months.

Think metabolically. Within certain ranges, your macronutrient consumption is affecting your hormone (esp. insulin) levels. The hormone levels are then directing what happens to the fat, protein and carbs that you eat, such that your weight depends directly on the hormones, but only indirectly on the macronutrient ratios. ( See your bible -GCBC by Taubes)

How else could it be, really? Paleo man and Hunter/Gatherer tribes don't count or measure anything. What they do is avoid the neolithic agents of wheat, linoleic acid and fructose. In the same way, as long as we don't perturb our metabolism with gluten grains, excess (note I did not say zero) fructose or linoleic acid, and we stay below, say, 25% carbs when living in a modern food-abundant environment, our bodies should be able to tolerate some variation.

It is not likely that for most healthy humans, that it makes any difference if carb intake is 20% or 10% or 5%, once your basal insulin levels and AUC (area under the curve) for glucose is optimally low. Remember, even if you eat zero carbs, you will still have a basal insulin need to handle the glucose made via gluconeogenesis. You cannot make glucose disappear from you body. It would kill you to do so.

It's helpful to think of oxygen. Oxygen is (duh!) a powerful oxidizing agent. Too high a concentration of oxygen in your air can actually be fatal, but would you try to go scuba diving with a tank that holds only nitrogen? Similarly, elevated Glucose and Insulin levels are the likely causes of many of the diseases of civilization, but you will die without them.

PaNu focuses on removing the noxious neolithic agents as that is what science and evolutionary reasoning implicate in the diseases of civilization. It is neither biologically nor historically plausible that more precise macronutrient ratios should make a difference. Most folks who follow my approach have great success with no more measuring or weighing than I employ.

I will discuss some exceptions in upcoming posts, as well as providing more thoughts on macronutrient ratios and ketosis.

 

 

 

Reader Comments (46)

I love your posts. They are by far the best on the internet. I live in Canada and am having a hard time finding a doctor that prescribes to the panu approach. Do you know of any in this area?

August 25, 2009 | Unregistered CommenterJim

Toronto that is.

August 25, 2009 | Unregistered CommenterJim

Great post, Thanks Kurt!

August 25, 2009 | Unregistered CommenterDanny Roddy

Someone well-known in the ZC community has claimed that "triglycerides cannot be 'transported to the adipose tissues, it MUST be converted from glucose within the adipose cells" , and "neither liver or dietary sourced triglycerides can enter an adipose cell, period- this is not conjecture- it has been shown by radioactive-tagged glucose and triglyceride metabolism."

This paper, Distribution of radioactive glycerol and fatty acids among adipose tissue triglycerides after administration of glucose-U-14C, appears to suggest that in the presence of glucose, fatty acids do indeed significantly influence adipose tissue synthesis.

So a question I have for you Kurt, is whether a certain level of insulin is required to synthesize adipose tissue. i.e. Do insulin levels have to be elevated beyond basal? If calories exceed dietary requirements, can fat be stored in the absence of insulin?

August 25, 2009 | Unregistered Commenterwebster

Nice one Webster! You are correct, without insulin- you wouldn't be able to store fat -- just look at type 1s. Even on a high fat diet without carbs however-- you have to eat some protein-- and protein will stimulate an insulin response-- hense, you can store fat.

You need insulin-- it does have a purpose!

August 26, 2009 | Unregistered CommenterAaron

One slight correction- I forget the study-- but there is some proof that fat can can stored all on its own-- I'll have to dig it up!

August 26, 2009 | Unregistered CommenterAaron

Webster and Aaron

TGs can be disassembled into NEFAs (non-esterified or free fatty acids) and glycerol and either consumed, transported, or stored wherever they are needed (except across the blood brain barrier).

If only glucose can be stored as fat, why isn't everyone on zero carb at 0% body fat?

Every molecule in your body depends on a dynamic equilibrium. If you stop storing fat, glycogen, etc you will lose fat, glycogen, etc.

Jim

Can't help you but you shouldn't need a medical professional unless you have medical issues like thyroid or diabetes.

I am flattered you thought my approach might be franchised, though!

August 26, 2009 | Unregistered CommenterKurt G. Harris MD

So your daily menu is pretty much eggs, cream and butter -- seafood and meat are only on the table a few times a week? That seems kind of monotonous, as much as I like all three (btw, am I mistaken or did you mention in another post drinking heavy cream straight up -- I thought I was the only one who enjoyed that!)

I'd be interested in what your diet looks like in detail. Macronutrient composition, food items, etc. Maybe do a post on that some time? Sprinkled with a blood panel, if possible!

- JLL

August 26, 2009 | Unregistered CommenterJLL

Nice article in layman's terms.

August 26, 2009 | Unregistered CommenterGrok

JLL

I mentioned these as the staples and core of what I eat and I guarantee you it suits me fine. Notice that nowhere do I say that is what you should eat. If you ape what you assume to be my exact diet and find that monotonous that would only be because you lack imagination in the kitchen or are assuming that is all I ever eat or all that you are allowed to eat.

PaNu is about what not to eat. Seems like I have to say that a lot.

Red meat can be beef, venison, elk, buffalo, lamb, etc. We have mushrooms of several varieties. garden grown tomatoes, locally grown asparagus, charntarelle and morel mushrooms in season from my private woodlot, etc.

We also eat a variety of gourmet cheeses alongside our pastured dairy products and quite bit of locally wild caught fish , including salmon from lake michigan, and perch and walleye.

Does that really sound monotonous?

My wife and I are not former fatties nor food obsessives. We are both decent cooks and our home-cooked meals are better than most restaurants.

We enjoy our food but view it primarily as nourishment, not entertainment.

August 26, 2009 | Unregistered CommenterKurt G. Harris MD

I really enjoy your posts Dr. Harris.

Like many other diet focused blogs you might become inundated with people obsessing over the minute differences between your diet and what other paleo/low-carb bloggers claim is an ideal diet, but I like your approach as it is more of a personal and less structured way of eating in the low-carb/paleo tradition.

I suspect that the propaganda authorities are very good at taking the fact that we do require some amounts of glucose to push the idea that low carb is dangerous because "we need glucose to survive" while avoiding direct analysis of how much (or how little) we actually need.

I know many people (including myself) who spent considerable amounts of time obsessing about carbs attempting to go near zero but upon further analysis realizing we were eating much more carbs than we realized in the form of balsamic vinegar's, tomato's, bbq -type sauces and veggies. I see no merit in obsessing gram by gram when a range-bound approach seems more approachable and relieves some of the neurotic tendencies of this dietary approach.

Based on your post and other readings of glucose, it would appear that even 5-10 grams of carbs a day would be sufficient for an average person that eats a good range of pastured meats/fats, and a variety of other paleo foods.

I hope this makes sense, I really enjoy this blog, its a great compliment to the paleo/low-carb info out there on the net.

August 26, 2009 | Unregistered Commenterd. cosa

Hi Kurt,

I think you get requests for samples of your diet as people (me included) like real-world examples and cookie-cutter approaches. Makes it easier somehow. Dr Eades posts showing a photo diary of his meals are some of his most popular.

Having said that; what are your views on pork? Belly, bacon, sausages, chops, crackling etc. Eggs? Good PaNu option?

Regards,

WP

August 26, 2009 | Unregistered Commenterwinalot

I KNEW there was something i just "wasn't getting" and now i think i get it... thank you!

one thing though- i have access to pasture butter & eggs, and raw cheese(YUM might i add)...but only "organic ground beef, chicken or turkey" and occassionally they have salmon but it is "farm raised". how much of an impact do grain fed steaks and "no hormone" chicken have in the PaNu approach?

i have nothing wrong with the what is "organic" grounds meats, but i do enjoy a good steak however it is grain fed from the butcher.

Mississippi does not have the luxury of other states when it comes to pure and healthy foods

thanks for the blog!

August 26, 2009 | Unregistered Commentermallory

Kurt:

Just wanted you to know that I have read all of your past posts, and your blog is one of my top three daily "must reads". If I'm not mistaken, you mentioned in a prior post that you live in Door County WI? I'm down in Racine...small world!

I have been "lacto-paleo" since March 1, and have lost 28 pounds (only 10 more to go). I too make heavy cream, raw butter and eggs daily staples in my diet. I also eat "boutique" hard imported cheeses from Ireland, Holland, Switzerland and Italy. They are highly aged, quite crumbly, and are almost what I would call crystalized somewhat.....yum!! I eat local, fresh veggies daily but only with my evening meal. The only veggies I don't eat are potatos, corn and legumes. I wish I could stomach mushrooms, but have never cared for their texture.

Anyway, thank you for a very easy to read and highly informative blog!

Jenny

August 26, 2009 | Unregistered CommenterJenny Light

webster,

About the zero-carb guru and his contention that fatty acids in adipose cells only come from carbs (glucose) - it's a bunch of hogwash. Essential fatty acids are found in fat cells. Since, by definition, humans can't synthesize EFAs from glucose, how did they get there if not from dietary sources? Also, studies have shown that the fatty acid profile of samples of adipose tissue closely mirror the fatty acid intake of the diet.

http://www.ajcn.org/cgi/content/abstract/54/2/340 (sorry, I couldn't hyperlink)

August 26, 2009 | Unregistered CommenterJoselyn

Jenny and Mallory

-Thank You

Jenny
- Congratualtions on the weight loss that is a side effect of proper diet!

Mallory

I'l make a general post about organic and how that term means nothing in the future. Think grass fed and pastured. Organic and hormone free is largely a marketing scam and often organic does not mean grass fed.

D Cosa

50 g a day is the estimated requirement to keep out of ketosis and the amount our brain and blood cells need, not 5-10 g

Joselyn

The idea that fats from our diet cannot be stored in adipocytes can be refuted with a quick peek at most undergraduate biochemistry texts. That idea is nonsense. EFAs are in the walls of every cell, actually.

Winalot

It's harder to find pastured non grain fed pork with healthy ratios than it is beef or bison. I don't usually eat industrial chicken at all. I'd rather eat cardboard than a skinless chicken breast -leave that to Dean Ornish. I think bacon is OK now and then and I love prosciutto ham but don't have it that often. Locally made sausage links for breakfast about 2 x per week.

It would be reasonable to start a cult around pastured eggs. I average 4 -6 per day (because I like them and they are convenient, by all means eat grass fed ribeyes if you prefer) They are the most highly ranked food in my universe. You could live pretty well on nothing but eggs and pastured cream for a very long time. Maybe we should call our cult "Ovozero" and start a new forum?

All -

I appreciate the legitimate desire to do dietary modeling. I will possibly post more about what to eat in the future. However, I am not a foodie and most days what I eat is satisfying but not photogenic.

I am trying to emphasize the philosophy of PaNu and what makes it different. If you stay within the parameters of what to avoid, you can otherwise eat whatever you want. It does annoy me I suppose when people ask me what I eat and then tell me it sounds monotonous. How many people do you know who eat the exact same breakfast cereal every day of their lives or go to Mickey D's and get the "number 7" every single day for lunch? I also have noticed that the complaint of VLC diets being boring is often made my people who have just switched from an even more monotonous diet that was loaded with sugar, bread and pasta. In that case, monotonous is coded language for "not sweet enough" or "not full of opiate peptides from grains".

These are just observations, not saying any poster here has such an issue.

August 26, 2009 | Unregistered CommenterKurt G. Harris MD

re: pork. isn't most of the fat saturated? [in which case ratios aren't an issue.]
from wikipedia re lard:
Fat composition
Saturated fats 38–43%:
............Palmitic acid: 25–28%
............Stearic acid: 12–14%
............Myristic acid: 1%
Unsaturated fats 56–62%
.....Monounsaturated fats 47–50%:
............Oleic acid: 44–47%
............Palmitoleic acid: 3%
.....Polyunsaturated fats Linoleic acid: 6–10%

so the linoleic is omega-6, but only 10% of the content. in general, i thought lard was ok.

August 26, 2009 | Unregistered Commenterjeff klugman

Hey Dr. Harris.
I'm in a gushy mood so thought I'd chime in and say hi and thanks for the great blog. I'm down the road in chicago and eat a lot of Wisconsin foods from the farmers market. I'm with you on the bland not being bland. I've had lamb organs and ground lamb with sweet potatoes in some form or another for the last 5 meals and it gets better every time. Next we'll break into the pork ribs or beef hearts. Lots of cream and butter here too. The restaurants just can't compare. We were out for indian the other day and I had to ask what they use for cooking oil. Some mystery veggie oil. Back home to pop some fancy fermented skate wing oil. It's difficult to dine out and think you can avoid sugar, omega 6, and fructose.
So while we're all kissing ass and asking questions; it's question time. I like the idea of JK optimal diet. I eat a quick potato- usually yams to get my body out of ketosis and replenish a bit of glycogen for workouts. Is the glycemic issue worth worrying about here? We buy veggies eat some and watch the rest of them wilt. We eat tomatoes, and I drink whole milk usually with a shot of cream added, and yogurt. Some berries. Also gluten free beer. Had a regular ale last night and woke up with the old times hip ache.
Man, thanks for the blog. I'm tired just writing these run-on confusing sentences.

August 26, 2009 | Unregistered Commenterwes

I now feel ripped off for buying "organic" ground beef today....damnit. i did get the phone number to a guy who supposedly sells grass fed meat here in mississippi, but according to the state it is illegal to sell because the demand is not large enough, and other things must come and happen first before we will ever get a whole foods store. thats a shame.

annoying is not monotany in what you eat...annoying is the fact that a place like MS will not sell grassfed and healthy meat and produce.. should be illegal!

August 26, 2009 | Unregistered Commentermallory

Hi Jeff

According to several of my sources (which vary of course) the ratio in factory pork is much worse than factory beef.

The importance of the ratio when only 10% of the fat is PUFA depends on how much of your diet is from fat. If you are say, getting 40% of your calories from lard, you will be getting 4% of calories from PUFA. If nearly all the PUFA is O-6, you could then be getting an awful lot of O-6. You might have close to 4% of calories from 0-6 not counting your other food. That is better than 10 or 15%, I suppose. Your 6:3 ratio in your body would better than those on the SAD but would be more american than japanese.

If you ate pastured butter instead of lard as 40% of calories you would get about 1.5 % of calories from each O3 and O6 in a 1:1 ratio. Big difference!

So eating occasional factory pork is no big deal but cooking a lot with typical lard is less healthy than pastured butter or beef fat. Grass fed is preferred. Finding grain free pigs is hard and ruminants have the advantage in better ratios in general (ceteris paribus)

I might as well warm you about chicken. Chicken fat is not only 25% or more PUFA, it has terrible ratios.

If your point is that avoiding salad dressing in soybean oil is 10x more important than worryiing about pork or lard, then I totally agree!

I have "adjust your 6s and 3s" down the list but 90% of the adjustment is further up where we are eliminating the industrial vegetable oils

You won't' believe how many people pay for grass fed beef but use industrial oil laden salad dressings.


Mallory

Google Pop's grass fed beef and order "Jason's special"
For pastured butter, google pastureland dairy in minnesota

Wes

Sounds like you have it wired. I say if you like a few sweet potatoes and your HBA1c and fasting insulin are low (or you have no reason to suspect they are not low) eat them!

August 26, 2009 | Registered CommenterKurt G. Harris MD

Mallory,

Most of these folks ship (with dry ice, for safety) -

http://www.eatwild.com/products/texas.html

Slanker's, in particular, breaks out the products and the shipping in considerable detail.

HTH

August 26, 2009 | Unregistered CommenterAnnlee

Thank you Joselyn for your response to my post and giving me the article.

Has anyone else interpreted that article to suggest that dietary Saturated fats are LESS likely to store in adipose tissue?

What you and Kurt say makes sense - clearly dietary fats CAN be stored in adipocytes. However, what I still don't understand, is how much insulin is required, if any, for this to happen? Maybe when most dietary fats are stored, this occurs when insulin is higher, say 60% fat:40% protein, but when the same calories go to 85% fat: 15% protein, it's far less likely that adipose tissue would be synthesized (?)

August 26, 2009 | Unregistered Commenterwebster

Webster,

"Has anyone else interpreted that article to suggest that dietary Saturated fats are LESS likely to store in adipose tissue?"

I wouldn't be surprised if that were the case. In rabbits, fat storage depends on the type of fatty acid in question. When you feed them lots of saturated fat, only some of it ends up as saturated fat in adipose tissue, but when you feed them lots of polyunsaturated fat, almost all of it ends up as PUFAs in adipose tissue. This is probably because the body is able to desaturate and retroconvert saturated fats pretty well when there's an excess, but an excess of PUFAs is a problem.

August 27, 2009 | Unregistered CommenterJLL

thanks for the response doctor,

but is staying out of ketosis a good thing from your perspective?
i have never fully understood the concept and weather it was a critical function of a good paleo/low carb diet.
ive been eating about 20g a day give or take for a few years under the impression the lower the better.

thanks!!

August 27, 2009 | Unregistered Commenterd. cosa

IM CHECKING OUT THOSE WEBSITES THANK YOU!

August 27, 2009 | Unregistered Commentermallory

just placed my order from Pop's Beef!!!! It should be here next week im thinkin because they ship monday and tuesdays fedex!! i cant wait...thanks again!

August 27, 2009 | Unregistered Commentermallory

Hi Kurt,

Eggs and cream sounds good to me. Reminds me of the Vince Gironda staple of heavy cream mixed with half+half and a dozen-eggs a day - ideal for muscle building. He advised whipping it until stiff and eating with a spoon throughtout the day to maintain positive hormone balance. Thirty years ago but he was ahead of his time!

What benefit is there to using butter for cooking vs. suet/tallow vs. pork lard vs. goose fat say?

Regards,

WP

August 27, 2009 | Unregistered Commenterwinalot

d.cosa

I haven't weighed in on whether I think it is important to avoid ketosis because I don't have a strong opinion on it yet.

I definitely think some with a "broken metabolism' need to get into ketosis for a while to restore their insulin resistance. Some may even need to stay there.

I am pretty sure a ketogenic diet can be therapeutic for a variety of brain disorders and maybe even cancer.

What I don't know is if it is better (or worse) in general to always be in ketosis once your insulin and glucose levels are optimized.

WP

butter has low overall PUFA levels and if pastured the ratio is about 1:1

That makes is best in my book, but grass fed tallow or suet would be good too.

Kwasniewski likes lard but he may be from a country where grains are too expensive to feed to pigs.

Don't know much about goose fat but chicken fat is high in PUFA

August 27, 2009 | Registered CommenterKurt G. Harris MD

webster,

What I took from the article is that dietary saturated fat intake does not correlate with adipose tissue sat fat content because fat cells can make saturated fatty acids from glucose. I have read before that sat fat is not as easily stored in fat cells as unsaturated fat but I can't remember where I read it. I'll have to read the article again to see if it hints at that because I didn't read it with that idea in mind originally.

As for how much insulin is required to store fat, I can't say with any certainty. Obviously, you need some - Type 1 diabetics demonstrate this - but would the insulin response from an 85% fat/15% protein diet be enough to store a large portion of the fat? I just don't know and I've been trying to figure it out for some time now ;) Something interesting that I've learned along the way is that in humans during a prolonged fast, about 40% of the fatty acids released from fat cells are re-stored (re-esterified in fat cells to become part of a triglyceride molecule again) before they leave the local environment. So basically, fat cells release fatty acids and before they can go anywhere they are taken up and stored again in the fat cells. This happens during a period of low insulin (prolonged fasting). IMHO it begs the question: If fat cells can store fat (form triglycerides from fatty acids) during fasting when insulin is low, can they also store dietary fat during VLC dieting when insulin is also low? Definitely food for thought.

August 27, 2009 | Unregistered CommenterJoselyn

Joselyn

Fat stores are not static. Storage fat is in an equilibrium state with esterification and lipolysis in balance.

Therefore, you are definitely storing fat while on VLC or ZC or any kind of low carb diet. You are also liberating fat while on a high carb diet.

Whether you are losing or gaining depends on the balance between storage and release.

Think filling your gas tank while the engine is running. The fuel level depends on the balance of the two processes.

This balance is under hormonal control. Neither storage nor release ever ceases, the balance just changes.

August 27, 2009 | Unregistered CommenterKurt G. Harris MD

"Fat stores are not static. Storage fat is in an equilibrium state with esterification and lipolysis in balance."
<snip>
"Whether you are losing or gaining depends on the balance between storage and release."


Oh yes, I'm absolutely convinced that's how it works. I was responding a little more in detail to what I think webster was getting at, since he seems familiar with what zero-carbers espouse: that fat cells cannot take fatty acids and form triglycerides with them without elevated insulin and blood sugar because there would be no source of glycerol phosphate (or very little) under those circumstances. I just wanted to show that they can and do, at least under the condition of prolonged fasting.

On a different topic, I'm disappointed that you don't think chicken is optimally healthy. I LOVE oven-roasted chicken with rosemary. I'd take it over a ribeye any day!

August 27, 2009 | Unregistered CommenterJoselyn

Joselyn

When you said:

"If fat cells can store fat (form triglycerides from fatty acids) during fasting when insulin is low, can they also store dietary fat during VLC dieting when insulin is also low?"

I took that to be a question. The answer is yes.

Chicken is better than bread, but ranks low in my meat hierarchy especially factory chicken.

August 27, 2009 | Registered CommenterKurt G. Harris MD

I just found your articles and I must say I'm quite impressed with them. Tthe quality of comments is also superb.

In your article, you mentioned excess protein is needed for the glucose required by your body, or else we'll experience muscle wasting. Can I ask what you think is an appropriate amount of protein to be eating? I generally shoot for 100-150g a day with a ZC woe.

August 27, 2009 | Unregistered CommenterRoberto

Roberto

Thank You

On ZC, and once you are ketoadapted (after a few months) approximately 75 g a day of your protein is
going to GNG for glucose production.

If ZC is working for you, I would stay at the upper end of that range for total protein to make sure you have enough. Estimates of structural protein requirements on VLC or LC range from .8 to 1.2 g/kg/day

If you are 70 kg, that would be a range of 56 to 84 on top of the 75 g converted to glucose. (total 131 to 159)

So 150 would be good to shoot for. On 2000 kcal/day that would be 70/30.

August 27, 2009 | Registered CommenterKurt G. Harris MD

Thank you, Kurt. I really appreciate all this quality information!

I recently found that eating as much as I want on ZC (few months in) only resulted in me gaining fat. Once I fixed my protein to a certain range and added fat to compensate for hunger (and how little fat is actually needed), I started losing. I'm glad that it seems the weight loss isn't muscle!

August 28, 2009 | Unregistered CommenterRoberto

Roberto

You experience confirms that you can indeed store fat with no carb consumption if you are eating high enough protein and total calories. Fits with what I know of biochemistry and metabolism.

Again, calories in is not calories out, but if you eat enough to exceed the tolerable range, you may well cause enough increase in insulin to have net fat storage.

Seems simple in theory and I've sure seen it in practice.

August 29, 2009 | Registered CommenterKurt G. Harris MD

Hello there Kurt and greetings from another "broad spectrum basic knowledge about the human organism and nutrition" type of MD.

My own journey started about 10 years ago, myself ended up in the "write a book" category to lessen the need to go over and over the same arguments again and again. :)

Now this is just a sort of drive-by-shooting kind of "hi there and keep on fighting the good fight" thing, this article tickled a "FYI"-nerve in me, so here comes in short:

Myself when I was researching the basics, I went through a lot of stuff about ketosis, as the misnotions about it were ubiquitous. Now the interesting parts of it regarding this glucose-from-glycerol pathway were that considering any anaerobic usage of glucose is reversable (blood cells, some few other places, sorry just writing this away from home so don't have the book (mine ;)) in front of me) and thus not really glucose depleting in a sense, the only remaining knowledge about the amounts of irreversible glucose utilization (which seems to occur mainly in the brain) ends up being eerily close to the amounts of possible glucose generated from released glycerol in a mainly fat-based energy metabolism. And of course, the reverse pathway from anaerobic glucose utilization back to glucose could also be "paid for" in fat-based energy. ;)

When I stumbled across the relevant informations, it definitely lit a lightbulb inside me:

"So ... it seems the human organism really uses about this much glucose irreversibly, and about similar amounts can be generated from released glycerol considering average energy expenditure ... wait a second, this smells like EVOLUTION!" :)

So while it really is sort of irrelevant "nice to know" information, as I'm with you that mainly humans just ate what was available, and thus no strict zero carb minimal protein events rarely happened, BUT if it did ... well, evolution seems like the best bet why it seems we can produce, or is that evolution seems like the best bet why we USE approximately the same amount of glucose as is realistically in minimum generated/ingested within ourselves?

Anyways, a little side detour, maybe it tickles you too in the "this makes sense" region of the brain, mostly irrelevant info though. :)

Cheers, and keep on talking to other MDs. I'm definitely picking up some behind the scenes changes in my country about carb conscious eating in some closed to public MD discussion forums, so me thinks we are slowly starting to break through. :)

PS. If parts of this seems a bit like free-flowing thoughts written down, don't worry, that's why I had the professional writer as the writing partner, to translate from gibberish to understandable language. ;)

October 10, 2009 | Unregistered CommenterEwert

If there would indeed be a thyroid disorder present (hypothyroidism, low), how would your dietary recommendations change?

October 26, 2009 | Unregistered CommenterMikael Jansson

Also, if you do resistance training on /zero/ carbs and you're set on establishing ketosis, what would be a good figure on protein requirements in g/kg?

October 26, 2009 | Unregistered CommenterMikael Jansson

Mikael

No change in diet - just making sure you are getting your hypothyroidism treated if you have it and not erroneously attributing metabolic changes to the diet when your thyroid is not working.

For resistance training, if you are getting in the 1 g/kg/day range and you eat some minimal carbs (.5 - .7 g/kg/day) you should have plenty of protien.

Ewert

If you have a reference proving the stoichiometry of glycerol to glucose from fatty acids is enough to meet basal glucose requirements of blood cells and brain on a high fat diet, I would love to see it. My back of the envelope calculation shows a small deficit that requires some at least some gluconeogenesis from amino acids.

October 26, 2009 | Registered CommenterKurt G. Harris MD

Kurt,

Thank you for your answers.

But, let's just suppose one were to eat meat and fish only, essentially zero carbs, the protein requirements would go up. However, if you'd want to minimize the insulin response caused by glucoid amino acids, and also eat zero carbs, what would be the proper (not too much for the insulin response, not too little for mucle waste) amount of protein per kg (or LBM kg)?

Been doing low-carb (10-50g) for over a year, but never zero-carb; thought it could be an interesting experiment both for undereating and overeating. But I don't want to risk losing muscle mass.

Thanks!

October 27, 2009 | Unregistered CommenterMikael Jansson

It takes about 50 g of excess protein to make 30 g of glucose.

October 27, 2009 | Unregistered CommenterKurt G Harris MD

Well, yeah, so the question is: how much protein is "excess"? :-)
Especially for someone doing weight lifting, that number seems to actually be unknown.

What would you say is a good protein number for someone doing resistance training, based on body weight (or LBM weight), and on ZC, to maximize fat loss (i.e. minimize insuline response) and minimize muscle loss?

Thanks again.

October 28, 2009 | Unregistered CommenterMikael Jansson

MJ

By excess I mean in excess of the estimated .8 g/kg/day basal requirement for protein I have discussed many times before and in agreement with many other sources including Jan Kwasniewski.

Can you do addition? If you weigh 70 kg you therefore need at minimum 56 g + 50 g = 106 g total. If you are smart you will not cut it that close, and you will leave a margin of error on the upside. All of these numbers are estimates, of course. YMMV.

October 28, 2009 | Unregistered CommenterKurt G Harris MD

"If you have a reference proving the stoichiometry of glycerol to glucose from fatty acids is enough to meet basal glucose requirements of blood cells and brain on a high fat diet, I would love to see it. My back of the envelope calculation shows a small deficit that requires some at least some gluconeogenesis from amino acids."

Googlebooks has Lyle McDonalds book "The ketogenic diet", and the relevant chapter on glycerol and gluconeogenesis has some of the references. Lyle uses the 40g/day brain usage number, but I have seen also references to around 20g/day glucose utilization for the brain in end-stage ketoadaptation, which I unfortunately don't remember in what papers they were in, since I'm more of a read&remember than read&write down person. Approx 10% of triglyceride weight is glycerol, so approximately 10% of "fat" grams is actually "glucose", in a "sort of, to put it simplistically" way. There are also the odd-chain-length fatty acids, from which the end bit is also a gluconeogenetic substrate, how much that means on average is something I have absolutely not even the faintest of ideas about.

Blood cells in mammals are anaerobic unlike in some other species, so blood cells do not "use" glucose, since the resulting lactic acid can be used as a substrate for gluconeogenesis, and thus recreated as glucose (with possibly fatty acid based ATP). Naturally gluconeogenesis of course does happen in fat based metabolism mode, but the need for amino acids as substrates can be eerily low, considering end-stage adaptation to ketone-usage in a extremely high-fat based metabolic state (such as starvation or zero-carb).

Whether it might ever be truly zero amino acid grams required for gluconeogenesis or not is theoretical anyways, in actual in vivo situations I doubt it will ever happen as the amino pool is always cycling, but the signs point to a very highly optimized system that will minimize protein needs for gluconeogenesis to possibly mere few grams per day.

October 28, 2009 | Unregistered CommenterEwert

Kurt,
Thanks much. I'm sorry for being nagging; I just hadn't found any specific information on this.

Ewert,

Then, after proper keto-adaption (glucose usage down to ~20g) and a fat intake at about 200g a day, the protein requirements could be drastically lowered, i.e. down to the standard 0,8g/kg value given. Correct? To actually fullfill your energy needs, say 2500 kcal, 75 kg, you could then go as low as 60g protein (240 kcal) and 250g of fat, giving 25g of glucose.

Would be interesting to see what actually happens when you have absolutely minimal insulin fluctuations and heavily overeat on fat -- would it be stored as fat, would your body temperature go up (quick fix for the common cold?) to compensate for the extra energy, or something else?

October 30, 2009 | Unregistered CommenterMikael Jansson
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