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Mike ODonnell
05-23-2007, 04:48 PM
a good article from Dr Eades' Blog
http://www.proteinpower.com/drmike/

Since posting the piece on ketone bodies and their causing breathalyzer problems I’ve had enough comments and emails to make me realize that there are probably many people unsure of what ketones really are, where they come from and why. Let’s take a look at the goals and priorities of our metabolic system to see what happens. I’m going to try to keep the biochemistry to a minimum, so fear not.

The primary goal of our metabolic system is to provide fuels in the amounts needed at the times needed to keep us alive and functioning. As long as we’ve got plenty of food, the metabolic systems busies itself with allocating it to the right places and storing what’s left over. In a society such as ours, there is usually too much food so the metabolic system has to deal with it in amounts and configurations that it wasn’t really designed to handle, leading to all kinds of problems. But that’s a story for another day.

If you read any medical school biochemistry textbook, you’ll find a section devoted to what happens metabolically during starvation. If you read these sections with a knowing eye, you’ll realize that everything discussed as happening during starvation happens during carbohydrate restriction as well. There have been a few papers published recently showing the same thing: the metabolism of carb restriction = the metabolism of starvation. I would maintain, however, based on my study of the Paleolithic diet that starvation and carb restriction are simply the polar ends of a continuum, and that carb restriction was the norm for most of our existence as upright walking beings on this planet, making the metabolism of what biochemistry textbook authors call starvation the ‘normal’ metabolism.

So, bearing in mind that carb restriction and starvation are opposite ends of the same stick and that what applies to one applies to the other, let’s look at how it all works. I’ll explain it from a starvation perspective, but all the mechanisms work the same for a carb-restricted diet.

During starvation the primary goal of the metabolic system is to provide enough glucose to the brain and other tissues (the red blood cells, certain kidney cells, and others) that absolutely require glucose to function. Which makes sense if you think about it. Your a Paleolithic man or woman, you’re starving, you’ve got to find food, you need a brain, red blood cells, etc. to do it. You’ve got to be alert, quick on your feet, and not focused on how hungry you are.

If you’re not eating or if you’re on a low-carbohydrate diet, where does this glucose come from?

If you’re starving glucose can really come from only one place and that is from the protein reservoir: muscle. A little can come from stored fat, but not from the fatty acids themselves. Although glucose can be converted to fat, the reaction can’t go the other way. Fat is stored as a triglyceride, which is three fatty acids hooked on to a glycerol molecule. The glycerol molecule is a three-carbon structure that, when freed from the attached fatty acids, can combine with another glycerol molecule to make glucose. Thus a starving person can get a little glucose from the fat that is released from the fat cells, but not nearly enough. The lion’s share has to come from muscle that breaks down into amino acids, several of which can be converted by the liver into glucose. (There are a few other minor sources of glucose conversion: the Cori cycle, for example, but there are not major sources, so we’ll leave them for another, more technical, discussion.)

But the breakdown of muscle creates another problem, namely, that (in Paleolithic times and before) survival was dependent upon our being able to hunt down other animals and/or forage for plant foods. It makes it tough to do this if a lot of muscle is being converted into glucose and your muscle mass is dwindling.

The metabolic system is then presented with two problems: 1) getting glucose for the glucose-dependent tissues; and 2) maintaining as much muscle mass as possible to allow hunting and foraging to continue.

Early on, the metabolic system doesn’t know that the starvation is going to go on for a day or for a week or two weeks. At first it plunders the muscle to get its sugar. And remember from a past post that a normal blood sugar represents only about a teaspoon of sugar dissolved in the entire blood volume, so keeping the blood sugar normal for a day or so doesn’t require a whole lot of muscular sacrifice. If we figure that an average person requires about 200 grams of sugar per day to meet all the needs of the glucose-dependent tissues, we’re looking at about maybe a third of a pound of muscle per day, which isn’t all that big a deal over the first day. But we wouldn’t want it to continue. If we could reduce that amount and allow our muscle mass to last as long as possible it would be a help.

The metabolic system could solve its problem by a coming up with a way to reduce the glucose-dependent tissues’ need for glucose so that the protein could be spared as long as possible.

Ketones to the rescue.

The liver requires energy to convert the protein to glucose. The energy comes from fat. As the liver breaks down the fat to release its energy to power gluconeogenesis, the conversion of protein to sugar, it produces ketones as a byproduct. And what a byproduct they are. Ketones are basically water soluble (meaning they dissolve in blood) fats that are a source of energy for many tissues including the muscles, brain and heart. In fact, ketones act as a stand in for sugar in the brain. Although ketones can’t totally replace all the sugar required by the brain, they can replace a pretty good chunk of it. By reducing the body’s need for sugar, less protein is required, allowing the muscle mass (the protein reservoir) to last a lot longer before it is depleted. And ketones are THE preferred fuel for the heart, making that organ operate at about 28 percent greater efficiency.

Fat is the perfect fuel. Part of it provides energy to the liver so that the liver can convert protein to glucose. The unusable part of the fat then converts to ketones, which reduce the need for glucose and sparing the muscle in the process.

If, instead of starving, you’re following a low-carb diet, it gets even better. The protein you eat is converted to glucose instead of the protein in your muscles. If you keep the carbs low enough so that the liver still has to make some sugar, then you will be in fat-burning mode while maintaining your muscle mass, the best of all worlds. How low is low enough? Well, when the ketosis process is humming along nicely and the brain and other tissues have converted to ketones for fuel, the requirement for glucose drops to about 120-130 gm per day. If you keep your carbs below that at, say, 60 grams per day, you’re liver will have to produce at least 60-70 grams of glucose to make up the deficit, so you will generate ketones that entire time.

So, on a low-carb diet you can feast and starve all at the same time. Is it any wonder it’s so effective for weight loss?

Craig Cooper
05-24-2007, 10:51 AM
Awesome.

Robb Wolf
05-26-2007, 09:16 AM
How did I overlook this post? Great stuff.

Brad Hirakawa
05-26-2007, 01:20 PM
New focus at work for a while is mitochondrial toxicity. Yippe.. those mitos are funky little probably-used-to-be-bugs.

I spend that last four days reviewing glycolysis, oxidative decarboxylation, ole Krebsie, ox-phos and the electron transport system. F-ing flashcards for the molecules, recopying notes, electron micrographs of that funky ATP synthase protein...

I should have just read a nice summary article like that one and saved myself the pain.

Mike ODonnell
05-26-2007, 06:06 PM
How did I overlook this post?

Because you are spending wayy too much time working on the nerd ship.....

Greg Everett
05-27-2007, 11:00 AM
great summary.

Pierre Auge
05-27-2007, 02:37 PM
New focus at work for a while is mitochondrial toxicity. Yippe.. those mitos are funky little probably-used-to-be-bugs.

I spend that last four days reviewing glycolysis, oxidative decarboxylation, ole Krebsie, ox-phos and the electron transport system. F-ing flashcards for the molecules, recopying notes, electron micrographs of that funky ATP synthase protein...

I should have just read a nice summary article like that one and saved myself the pain.

Brad whatever you just said made me feel really dumb! j/k

Robb Wolf
05-29-2007, 07:23 AM
Brad whatever you just said made me feel really dumb! j/k

That's odd...I was strangely aroused...

Brad Hirakawa
05-29-2007, 08:14 AM
Pierre,

Don't feel dumb, I copied that right out of Wikipedia.

Seriously, Wikipedia is my new biochem prof.

Brad

Mike ODonnell
05-29-2007, 01:21 PM
If I could add a wireless card and google toolbar for my brain....I'd be the smartest man around....

Craig Cooper
05-29-2007, 06:41 PM
I decided to ask Eade's about low carb diets and sprinting performance:

Dr. Mike,

Have you had any experience with LC diets being unable to provide fuel for intense exercise (sprinting, CrossFit Style Metabolic Workouts, etc.)?

This study:

http://www.nutritionandmetabolism.com/content/1/1/2

seems to suggest that after one has become fat adapted, endurance exercise performance returns to normal, but sprint performance remains poor. The suggested reason is that this type of exercise can not be fueled by fat, it must be fueled by glucose.

If this is true, does this mean that Paleolithic man’s ability to hunt while in ketosis was poor?

Hi Craig–

I’ve seen this same phenomenon reported in a number of papers. In long stretches of high-intensity exercise, performance falls off with a low-carb diet.

But, I don’t think that would impair Paleolithic man’s hunting ability or ability to survive. No Paleolithic man - irrespective of how much carb he consumed - was going to be able to out sprint a lion chasing him or was going to be able to run down a deer. Hunting was a group effort involving long bouts of low-intensity exercise (tracking and locating the game) and very short surges - just a few seconds at a time - of intense effort to bring it down.

I can’t see Paleolithic man indulging in sprints just to keep in shape, so there was really no necessity to evolve a system that would perform optimally under those circumstances.

Another thought…Paleolithic man was on a low-carb diet from birth. Modern man is on a high-carb diet from birth. Some modern men decide to go on low-carb diets later on. And they adapt relatively quickly as far as endurance exercise is concerned. Maybe the adaptation period for high-intensity exercise simply takes a lot longer than we think.

Cheers–

MRE

Brad Hirakawa
05-29-2007, 09:40 PM
"Another thought…Paleolithic man was on a low-carb diet from birth. Modern man is on a high-carb diet from birth. Some modern men decide to go on low-carb diets later on. And they adapt relatively quickly as far as endurance exercise is concerned. Maybe the adaptation period for high-intensity exercise simply takes a lot longer than we think. "

... also may want to consider the maternal diet in this respect. All theory fyi, I'm not a nutrition guy. But, lasting changes in gene expression can sometimes take a bit to set.

Brad

Robb Wolf
05-30-2007, 06:25 AM
Scotty Hagnas has been posting some sick times on WOD's like Angie...in a fasted, low carb state. I think one can become much more efficient at using ketones for energy but hepatic glycogen replacement may be at work here. Scotty is not doing burners EVERY day. One met con then several days of strength work. That time may allow for sufficient glycogen repletion to occur.

This is a point that has rattled in my head for some time: Should food availability dictate training for the health and longevity biased? It starts looking a bunch like devany's recommendations....a day or two here and there at very high work output, then many days of lower level activity. I'm not sure that this will put one at the absolute top of the food chain in CrossFit World...but I think it's pretty good.

Daniel Miller
05-30-2007, 09:10 AM
It seems as though workout frequency is an important part of this equation. If one is training to sprint on a frequent basis while eating low carb, then I'd imagine a lot of difficulty in training. The central point to the DeVany's writing seems to be intermittancy and using and element of chaos to create harmony.

A friend of mine trains a lot of high-level boulders. He put one on the Metabolic diet as this guys was getting ready for nationals a few years ago. His training was frequent almost daily bouldering sessions, campusing, one-arms, and GPP, with rest days being occupied by hiking in the front range of CO. He didn't do so well and felt 'out of it' and flat despite a pre-event carb load.

Since food availability is largely a choice for most of us, I would say that for the health and longevity biased, training and fuel should be in Consonance and dissonance with eachother. http://en.wikipedia.org/wiki/Consonance_and_dissonance
In other words, we make choices that allow for our knowledge of metabolic pathways to make our health harmonized with metabolically efficient and adaptable eating habits.

Craig Cooper
05-30-2007, 03:50 PM
I can’t see Paleolithic man indulging in sprints just to keep in shape, so there was really no necessity to evolve a system that would perform optimally under those circumstances.


I think that is the key there. I would imagine, based on my limited experience with paleolithic man, that any sprint-type work would have definitely been performed intermittently at best.

This is my favorite part of this whole mess, speculating what paleo man's lifestyle was like.

Not to say that trying to mimic their lifestyle as closely as possible is the key to health and longevity.

Mike ODonnell
05-30-2007, 07:17 PM
This is my favorite part of this whole mess, speculating what paleo man's lifestyle was like.

UNfortunately I do not think he played hockey....so after some time off and trying lower carbs....coming back to hockey was a disaster....completely bonked....got lean and then lost athletic performance....so now back to a reasonable carb diet...timed around workouts

Craig Cooper
05-31-2007, 06:50 AM
Mike, that's the biggest problem that I have with low carbing. I mean, yeah, health and longevity is great, but high intensity competitive sports are fun! I'm going to start playing hockey again after an almost 4 year hiatus and I can't imagine trying to fuel those efforts without carbs.

Robb Wolf
05-31-2007, 09:16 AM
I think you guys are right...taking advantage of that post WO window and squirreling carbs into the muscles quickly allows for some high intensity of training but it minimizes insulin spikes.

Pierre Auge
05-31-2007, 10:46 AM
How much time have you guys spent in the wild?

You do realize that animals live in a near constant state of heightened awareness just short of paranoia. I guess I would call it calm readiness.

Sprinting is play - quick escape - or the social hunt

even the largest of predators spend lots of time sprinting at short high intensities. Ever seen a polar bear hunt? Ever seen a fox hunt? It looks oddly similar though foxes are very small in comparison. Why would we be any different in our needs or habits? We are more adaptable - I think the argument against short high intensity output in evolution is an argument made by those who don't spend much time observing the natural world.

Knowing that I can't possibly out run a Lion doesn't mean I'm not going to damn well try! Its instinct and I think the argument is flawed...

Mike ODonnell
05-31-2007, 11:57 AM
My dogs sleep for 23 1/2 hours a day......and once in a while chase a squirell or mailman....and love to eat....add beer and you have my ideal lifestyle.

Craig Cooper
05-31-2007, 03:27 PM
Pierre, that just brings us back to the original question: How did paleolithic man fuel high intensity activity if he was in Ketosis for most of the year? Eade's thought on the subject is interesting:

Another thought…Paleolithic man was on a low-carb diet from birth. Modern man is on a high-carb diet from birth. Some modern men decide to go on low-carb diets later on. And they adapt relatively quickly as far as endurance exercise is concerned. Maybe the adaptation period for high-intensity exercise simply takes a lot longer than we think.

The fact that no one has been able to stick to strictly low carb and be able to perform well at high intensity efforts is interesting, but maybe they just didn't wait long enough.

Scotty's example poses another question: if he is able to maintain high levels of performance in a fasted, low carb state doing approximately 1 metcon effort/week, what is the limit? How often was paleolithic man able to "sprint for play" without bonking?

Robb Wolf
05-31-2007, 04:05 PM
Couple interesting links:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=6865776&query_hl=2&itool=pubmed_docsum

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=12651914&query_hl=8&itool=pubmed_docsum

this on is about sled dogs:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=9361887&query_hl=17&itool=pubmed_docsum


this one about decreased rhabdomyolysis in horses fed a higher fat diet:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?itool=abstractplus&db=pubmed&cmd=Retrieve&dopt=abstractplus&list_uids=9604030

What I was looking for was the rate of glycogen repletion during ketosis. I guess that is pretty dependant upon total energy intake and how much protein can get converted to glucose. I think a take home form all this reflects what Loren Crodain said in the Paleo Diet for Athletes. Essentially that although our ancestors were quite fit, even by modern standards they were not pushed to elite levels as athletes are today. Some of that elite level training will need more than ancestral levels of carbohydrate intake to fuel those efforts. What role that might play on health and longevity...tough to tell.

Brad Hirakawa
06-01-2007, 09:54 AM
Robb,

We "simply" need to engineer the production of isocitrate lyase and malate synthase back into our genomes?

Chuckles and snorts a nerd laugh.

You're right, we're geeks.

Brad

Scotty Hagnas
06-01-2007, 11:13 AM
I had suspected for a while that my performance in the glycotic pathway wasn't impaired any longer by carb restriction or fasting. Keep in mind that I've been doing this for several years now, and I did notice some drop off in ability early on. I strongly suspect that there are some more long term adaptations occurring within IF/low carb, but I'm not sure exactly how.

I am going to be doing quite a bit of sprint work this summer, coincidently, so that might be a good time to test performance during more frequent workouts. Of course, fruit season is almost here....

Scotty Hagnas
CrossFit Portland

Mike ODonnell
06-01-2007, 01:28 PM
I noticed after a weekend of Guinness binging....my perfomance in my hockey game last night for 2 hours was dramatically 100x better...felt like a million bucks....Guinness as the next pwo meal? Hmmmmm.....somehow I see it working.....

Chris Forbis
06-01-2007, 02:59 PM
I noticed after a weekend of Guinness binging....my perfomance in my hockey game last night for 2 hours was dramatically 100x better...felt like a million bucks....Guinness as the next pwo meal? Hmmmmm.....somehow I see it working.....

In college I remember having some excellent workouts on a Guinness hangover.

Guinness... for strength.

Robb Wolf
06-01-2007, 03:14 PM
Liquid Bread. Makes sense.

Brad Hirakawa
06-01-2007, 05:55 PM
... cold barley soup..