Home   |   Contact   |   Help

Get Our Newsletter
Sign up for our free newsletter to get training tips and stay up to date on Catalyst Athletics, and get a FREE issue of the Performance Menu journal.

Go Back   Catalyst Athletics Forums > Nutrition > General Nutrition

Reply
 
Thread Tools Display Modes
Old 05-23-2007, 04:48 PM   #1
Mike ODonnell
Senior Member
 
Mike ODonnell's Avatar
 
Join Date: Nov 2006
Posts: 3,596
Default Ketones and Metabolism

a good article from Dr Eades' Blog
http://www.proteinpower.com/drmike/

Quote:
Since posting the piece on ketone bodies and their causing breathalyzer problems Iíve 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. Letís take a look at the goals and priorities of our metabolic system to see what happens. Iím 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 weíve got plenty of food, the metabolic systems busies itself with allocating it to the right places and storing whatís 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 wasnít really designed to handle, leading to all kinds of problems. But thatís a story for another day.

If you read any medical school biochemistry textbook, youíll find a section devoted to what happens metabolically during starvation. If you read these sections with a knowing eye, youíll 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 Ďnormalí 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, letís look at how it all works. Iíll 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, youíre starving, youíve got to find food, you need a brain, red blood cells, etc. to do it. Youíve got to be alert, quick on your feet, and not focused on how hungry you are.

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

If youíre 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 canít 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 lionís 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 weíll 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 doesnít 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 doesnít 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, weíre looking at about maybe a third of a pound of muscle per day, which isnít all that big a deal over the first day. But we wouldnít 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 tissuesí 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 canít totally replace all the sugar required by the brain, they can replace a pretty good chunk of it. By reducing the bodyís 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, youíre 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, youíre 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 itís so effective for weight loss?
__________________
Fitness Spotlight
The IF Life
Mike ODonnell is offline   Reply With Quote
Old 05-24-2007, 10:51 AM   #2
Craig Cooper
Senior Member
 
Craig Cooper's Avatar
 
Join Date: Oct 2006
Location: Seattle, WA
Posts: 122
Default

Awesome.
__________________
My Fitness & Nutrition Blog
Craig Cooper is offline   Reply With Quote
Old 05-26-2007, 09:16 AM   #3
Robb Wolf
Senior Member
 
Robb Wolf's Avatar
 
Join Date: Oct 2006
Posts: 1,444
Default

How did I overlook this post? Great stuff.
__________________
"Survival will be neither to the strongest of the species, nor to the most intelligent, but to those most adaptable to change."
C. Darwin

Robb's Blog
Robb Wolf is offline   Reply With Quote
Old 05-26-2007, 01:20 PM   #4
Brad Hirakawa
Senior Member
 
Join Date: Oct 2006
Location: San Diego
Posts: 169
Default

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 Hirakawa is offline   Reply With Quote
Old 05-26-2007, 06:06 PM   #5
Mike ODonnell
Senior Member
 
Mike ODonnell's Avatar
 
Join Date: Nov 2006
Posts: 3,596
Default

Quote:
Originally Posted by Robb Wolf View Post
How did I overlook this post?
Because you are spending wayy too much time working on the nerd ship.....
__________________
Fitness Spotlight
The IF Life
Mike ODonnell is offline   Reply With Quote
Old 05-27-2007, 11:00 AM   #6
Greg Everett
Administrator
 
Greg Everett's Avatar
 
Join Date: Oct 2006
Posts: 1,738
Default

great summary.
__________________
Olympic Weightlifting: A Complete Guide for Athletes & Coaches

"Without a doubt the best book on the market about Olympic-style weightlifting." - Mike Burgener, USAW Senior International Coach

American Weightlifting: The Documentary
Catalyst Athletics
Performance Menu Journal
Greg Everett is offline   Reply With Quote
Old 05-27-2007, 02:37 PM   #7
Pierre Auge
Senior Member
 
Pierre Auge's Avatar
 
Join Date: Oct 2006
Posts: 529
Default

Quote:
Originally Posted by Brad Hirakawa View Post
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
__________________
NOTICE: Pierre Auge's opinions are subject to change at any time and without prior notice.

To give real service you must add something which cannot be bought or measured with money, and that is sincerity and integrity. - Douglas Adams
Pierre Auge is offline   Reply With Quote
Old 05-29-2007, 07:23 AM   #8
Robb Wolf
Senior Member
 
Robb Wolf's Avatar
 
Join Date: Oct 2006
Posts: 1,444
Default

Quote:
Originally Posted by Pierre Auge View Post
Brad whatever you just said made me feel really dumb! j/k
That's odd...I was strangely aroused...
__________________
"Survival will be neither to the strongest of the species, nor to the most intelligent, but to those most adaptable to change."
C. Darwin

Robb's Blog
Robb Wolf is offline   Reply With Quote
Old 05-29-2007, 08:14 AM   #9
Brad Hirakawa
Senior Member
 
Join Date: Oct 2006
Location: San Diego
Posts: 169
Default

Pierre,

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

Seriously, Wikipedia is my new biochem prof.

Brad
Brad Hirakawa is offline   Reply With Quote
Old 05-29-2007, 01:21 PM   #10
Mike ODonnell
Senior Member
 
Mike ODonnell's Avatar
 
Join Date: Nov 2006
Posts: 3,596
Default

If I could add a wireless card and google toolbar for my brain....I'd be the smartest man around....
__________________
Fitness Spotlight
The IF Life
Mike ODonnell is offline   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -7. The time now is 11:03 AM.

Powered by vBulletin Version 3.6.2
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Subscribe to our Newsletter


Receive emails with training tips, news updates, events info, sale notifications and more.
ASK GREG

Submit your question to be answered by Greg Everett in the Performance Menu or on the website

Submit Your Question
WEIGHTLIFTING TEAM

Catalyst Athletics is a USA Weightlifting team of competitive Olympic-style weightlifters with multiple national team medals.

Read More
Olympic Weightlifting Book
Catalyst Athletics
Contact Us
About
Help
Newsletter
Products & Services
Gym
Store
Seminars
Weightlifting Team
Performance Menu
Magazine Home
Subscriber Login
Issues
Articles
Workouts
About the Program
Workout Archives
Exercise Demos
Text Only
Instructional Content
Exercise Demos
Video Gallery
Free Articles
Free Recipes
Resources
Recommended Books & DVDs
Olympic Weightlifting Guide
Discussion Forum
Weight Conversion Calculator