Do we need to eat any carbohydrates?

Brad Hirakawa · 04-28-2004, 02:27 PM

Quick question:

Our (Crossfit) dietary guidelines includes the words, “and enough carbohydrates to fuel athletic endeavors” or something to that extent. My question, and please forgive my ignorance of biochemistry, is why do we need any dietary carbohydrates at all (this sentence is extreme just to bring up a point, as I realize that the vitamins and minerals in veggies and fruits are necessary). That is, can’t our bodies rely on dietary fats for the calories necessary to fuel our workouts? Or, is it the case that glycogen/glucose reserves (blood, muscle, liver, etc.) are needed for the muscles to work their best, and/or is it the case that glycogen/glucose reserves are needed for specific metabolic energy pathways (phosphagenic, glycolytic, or oxidative)?

Even if these are the reasons why we do need to consume carbohydrates, isn’t it possible that athletes who follow low carbohydrate diets will adapt? The term adapt in this context can certainly apply to a number of changes. If I learned anything in graduate school (focus on genomics), it was that our physiology is remarkably responsive, adjustable, and flexible.

I was thinking about these things last night as I sifted thought a comparative physiology book (great cure for insomnia). Some of the more proficient predators on the planet are strict carnivores, capable of breathtaking feats of “athleticism.” Of course, their metabolism and physiology is quite different than ours… but not that different at the rudimentary levels.

Of course, they also sleep 20 hours a day (what a nice life they must have). :-)

Ryan Atkins · 04-28-2004, 04:10 PM

Hi Brad,

Didn't Ray Audette claim that it's possible for a human to not only survive, but to thrive on a meat-only diet? I'm assuming he meant grass-fed meat with the fatty portions eaten as well. Then again, he also made some claims about food producation capacities that I think others have shown to be false, so I could be off base here.

Just a thought,

Ryan

Roy · 04-28-2004, 04:25 PM

Brad, Im glad you posted this because I was wondering the same exact thing. And while all of us are waiting for a good answer, here are a few thoughts that came to my mind:

1. When one eats more protein than their body can synthesise, the rest turns into......GLUCOSE?

2. There are essential amino acids and essential fatty acids, but not essential carbohydrates, unless of course we're talking essential vitamins and minerals found in fruits and veggies.

3. veggies are mostly fiber anyway, loaded with nutrients.

4. if it werent for almonds, walnuts, pecans, etc, I could NEVER psychologically follow a low carb plan...:wink:

Cheers

Roy

Larry Cook · 04-28-2004, 04:56 PM

Brad,
Faigin makes the statement in his NHE book that the body's actual requirement for carbohydrates is zero. Certain carb foods certainly have beneficial micro-nutrients, but he does not believe they are not essential. He references the eskimos as a population that thrives on a diet that is predominantly (and at times exclusively) fat and protein.
Larry

Lincoln Brigham · 04-28-2004, 04:57 PM

The problem with skipping carbs altogether is that many essential nutrients are in highest concentration in foods that happen to be high in carbs. Vitamins, minerals, fiber, etc. It's not the carbs we need per se, it's the nutrients carried by the carbs.

Larry Cook · 04-28-2004, 07:06 PM

Just noticed an extra "not" in the second sentence of my last post ... take out either one. Anyway, I can't say I have enough knowledge to either agree or disagree with Faigin but Lincoln's comment makes sense ... lots of good things in those fruits and veggies.
Larry

Paul Kayley · 04-29-2004, 03:10 AM

You may want to explore the legitimacy of the claims made in the following article regarding the need to stimulate the Pentose Phosephate Bioenergetic Pathway...

http://www.dragondoor.com/cgi-bin/ar...&articleid=186

Also, I have tried existing on next to no carbs and my performance suffered... but then I am very reliant upon having a well supplied glycolytic system for the sports I compete in.

I would summarise that the benefits and legitimacy of the need for stimulation of the pentose phosphate pathway needs clarification, and your specific sporting requirements need to be addressed.

Brad Hirakawa · 04-29-2004, 09:27 AM

Good info. thanks fellows!
Brad

Robert Wolf · 04-29-2004, 11:36 AM

I think we can live quite well on low or no carbs. I think it is however impossible to have the activity level we do with crossfit...which I think ties into proper, healthy gene expression:
http://jp.physoc.org/cgi/content/full/543/2/399
Robb

David Werner · 04-29-2004, 12:54 PM

I'm surprised that no one has mentioned eskimos yet. We know enough of the traditional societies of Northern Dwellers to know that numerous groups of people survived for significant portions of the year (6-9 months) on meat. Some of these groups subsisted mainly on caribou, some on reindeer, some on seals and/or fish. But when you live on frozen tundra you can count on no veggies. Absolutely nothing but meat and bones to eat. Yet these peoples survived for millenia, thrived even.

How much more evidence do we need?

What study is going to top the quality of results that can be deduced from thousands of years of survival in the arctic?

Activity level supportable by no carb eating? Have any of you tried hunting seals?

Dave Werner
Crossfit North

04-28-2004, 04:25 PM	#3
Roy Departed Profile: Join Date: Jan 1970 Posts: 328	Brad, Im glad you posted this because I was wondering the same exact thing. And while all of us are waiting for a good answer, here are a few thoughts that came to my mind: 1. When one eats more protein than their body can synthesise, the rest turns into......GLUCOSE? 2. There are essential amino acids and essential fatty acids, but not essential carbohydrates, unless of course we're talking essential vitamins and minerals found in fruits and veggies. 3. veggies are mostly fiber anyway, loaded with nutrients. 4. if it werent for almonds, walnuts, pecans, etc, I could NEVER psychologically follow a low carb plan...:wink: Cheers Roy
Roy Departed Profile: Join Date: Jan 1970 Posts: 328

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04-28-2004, 02:27 PM	#1
Brad Hirakawa Member Profile: Join Date: Oct 2002 Location: San Diego CA Posts: 761	Quick question: Our (Crossfit) dietary guidelines includes the words, “and enough carbohydrates to fuel athletic endeavors” or something to that extent. My question, and please forgive my ignorance of biochemistry, is why do we need any dietary carbohydrates at all (this sentence is extreme just to bring up a point, as I realize that the vitamins and minerals in veggies and fruits are necessary). That is, can’t our bodies rely on dietary fats for the calories necessary to fuel our workouts? Or, is it the case that glycogen/glucose reserves (blood, muscle, liver, etc.) are needed for the muscles to work their best, and/or is it the case that glycogen/glucose reserves are needed for specific metabolic energy pathways (phosphagenic, glycolytic, or oxidative)? Even if these are the reasons why we do need to consume carbohydrates, isn’t it possible that athletes who follow low carbohydrate diets will adapt? The term adapt in this context can certainly apply to a number of changes. If I learned anything in graduate school (focus on genomics), it was that our physiology is remarkably responsive, adjustable, and flexible. I was thinking about these things last night as I sifted thought a comparative physiology book (great cure for insomnia). Some of the more proficient predators on the planet are strict carnivores, capable of breathtaking feats of “athleticism.” Of course, their metabolism and physiology is quite different than ours… but not that different at the rudimentary levels. Of course, they also sleep 20 hours a day (what a nice life they must have). :-)

04-28-2004, 04:10 PM	#2
Ryan Atkins Member Profile: Join Date: Feb 2003 Location: Racine WI Posts: 925	Hi Brad, Didn't Ray Audette claim that it's possible for a human to not only survive, but to thrive on a meat-only diet? I'm assuming he meant grass-fed meat with the fatty portions eaten as well. Then again, he also made some claims about food producation capacities that I think others have shown to be false, so I could be off base here. Just a thought, Ryan

04-28-2004, 04:56 PM	#4
Larry Cook Member Profile: Join Date: Jan 2004 Location: Cheshire CT Posts: 274	Brad, Faigin makes the statement in his NHE book that the body's actual requirement for carbohydrates is zero. Certain carb foods certainly have beneficial micro-nutrients, but he does not believe they are not essential. He references the eskimos as a population that thrives on a diet that is predominantly (and at times exclusively) fat and protein. Larry

04-28-2004, 04:57 PM	#5
Lincoln Brigham Member Profile: Join Date: May 2003 Location: Kirkland WA Posts: 3,987	The problem with skipping carbs altogether is that many essential nutrients are in highest concentration in foods that happen to be high in carbs. Vitamins, minerals, fiber, etc. It's not the carbs we need per se, it's the nutrients carried by the carbs.

04-28-2004, 07:06 PM	#6
Larry Cook Member Profile: Join Date: Jan 2004 Location: Cheshire CT Posts: 274	Just noticed an extra "not" in the second sentence of my last post ... take out either one. Anyway, I can't say I have enough knowledge to either agree or disagree with Faigin but Lincoln's comment makes sense ... lots of good things in those fruits and veggies. Larry

04-29-2004, 03:10 AM	#7
Paul Kayley Member Profile: Join Date: Sep 2003 Location: York North Yorkshire Posts: 195	You may want to explore the legitimacy of the claims made in the following article regarding the need to stimulate the Pentose Phosephate Bioenergetic Pathway... http://www.dragondoor.com/cgi-bin/ar...&articleid=186 Also, I have tried existing on next to no carbs and my performance suffered... but then I am very reliant upon having a well supplied glycolytic system for the sports I compete in. I would summarise that the benefits and legitimacy of the need for stimulation of the pentose phosphate pathway needs clarification, and your specific sporting requirements need to be addressed.

04-29-2004, 09:27 AM	#8
Brad Hirakawa Member Profile: Join Date: Oct 2002 Location: San Diego CA Posts: 761	Good info. thanks fellows! Brad

04-29-2004, 11:36 AM	#9
Robert Wolf Member Profile: Join Date: Oct 2002 Location: Chico CA Posts: 2,669	I think we can live quite well on low or no carbs. I think it is however impossible to have the activity level we do with crossfit...which I think ties into proper, healthy gene expression: http://jp.physoc.org/cgi/content/full/543/2/399 Robb

04-29-2004, 12:54 PM	#10
David Werner Affiliate Profile: Join Date: Oct 2002 Location: Seattle WA Posts: 399	I'm surprised that no one has mentioned eskimos yet. We know enough of the traditional societies of Northern Dwellers to know that numerous groups of people survived for significant portions of the year (6-9 months) on meat. Some of these groups subsisted mainly on caribou, some on reindeer, some on seals and/or fish. But when you live on frozen tundra you can count on no veggies. Absolutely nothing but meat and bones to eat. Yet these peoples survived for millenia, thrived even. How much more evidence do we need? What study is going to top the quality of results that can be deduced from thousands of years of survival in the arctic? Activity level supportable by no carb eating? Have any of you tried hunting seals? Dave Werner Crossfit North