Please explain low carbs and it's magical proprieties

mammamaurer

mel3491

Great analogies! I agree.

suprzonic

I need it explained in simple terms from those who swear by it. I feel like a moron but I really do not understand how you can lose faster than just a calories deficit and I am not talking about glycogen or water weight. My friend is doing it but is unable to explain how it work lol

Thank you

Hi - I've been low-carbing for a few months. I got some non-science type easy to understand info on healthy eating from web sites of zoe harcombe and jonathan bailor

para-phrasing from zoe harcombe for you (not plagiarism because I'm not claiming this stuff as my own!)

“…. exercise and BMR require quite different calories. Exercise is arguably best fuelled by carbohydrate (it provides glucose quickly for the body to use). BMR activities need fat, protein, vitamins and minerals. Carbohydrates can be useful for the vitamins and minerals they provide, but the macro nutrient, the carbohydrate itself, can only be used for energy – not cell repair and fighting infection …. it can’t be used for body maintenance – you need to burn if off down the gym or you will gain weight.
…. The body will always use carbohydrate for fuel first. Hence, if our average person has any glucose in the blood stream or any glycogen (stored glucose) in the body – this will be used to cover any gap in food eaten or activity done. The body can only burn fat when there is no glucose/glycogen available.”

"That’s a significant advantage for dieters and helps to explain the effectiveness of low carbohydrate diets."

See: http://www.zoeharcombe.com/the-knowledge/eating-less-will-not-make-us-weigh-less/
and http://thebailorgroup.com/

Both authors provide scientific references

I don't think of what I'm doing as low carb. It's more a nutrient dense diet. I'm swapping the starchy carbs and crappy fats for calories with non-starchy carbs - lots and lots and HEAPS of vegetables. and healthy fats. It's so much more food! I'm happy pigging out on low carb - and losing weight.

tigersword

Ah Gyuten's.

__________________________



The twelfth edition of Guyton and Hall Textbook of Medical Physiology continues this best-selling title's long tradition as one of the world's favorite physiology textbooks. The immense success of this book is due to its description of complex physiologic principles in language that is easy to read and understand. Now with an improved color art program, thorough updates reflecting today's medicine and science, and accessible online at Student Consult, this textbook is an excellent source for mastering essential human physiology knowledge.

Learn and remember vital concepts easily thanks to short, easy-to-read, masterfully edited chapters and a user-friendly full-color design.
See core concepts applied to real-life situations with clinical vignettes throughout the text.
Discover the newest in physiology with updates that reflect the latest advances in molecular biology, cardiovascular, neurophysiology, and gastrointestinal topics.
Visualize physiologic principles clearly with over 1000 bold, full-color drawings and diagrams.
Distinguish core concepts from more in-depth material with a layout that uses gray shading to clearly differentiate between "need-to-know" and "nice-to-know" information.
Access the complete contents online at Student Consult along with bonus resources such as image banks, self-assessment questions, physiology animations, and more!

This new edition continues the long tradition of "Guyton" as one of the world's favorite physiology textbooks.

____________________________________________________________

Aw, a college textbook with pictures and stories! I think I read something like this in Biology 101.

Keep studying it Steve. You have lots to learn yet. And discover PubMed!! Textbooks cannot be expected to keep up as new research is constantly being published in journals.

I believe its latest update was in 2010. It's 4 years behind the times now.

LOL!

I see you can google it.

Can you read it and appreciate it?

Guyton's IS the times. Guyton's IS the gold standard of physiology. Guyton's IS the best and most veracious of all the journal articles.

All sorts of crappy studies and theories come out every year.

They have to be tossed around and evaluated, and the experiments repeated. Conferences are held all over the world to determine what is true and what is garbage.

It is called the scientific method.

It takes time.

Guyton's will have another edition out soon and there will be changes- maybe large ones. We don't know.

Your ignorance is amusing. And....somehow endearing.

What is your background- do you have a college degree? If so, in what?

I think the dieters want to know. Especially with your haughty stance on Guyton's. (LOL redoux)

I hope the people reading this who are sincerely wanting to lose weight will get the right message.

What exactly is your college degree? High school dropout? I mean, you completely failed to answer ANY question asked of, nor have you provided ANY actual evidence for any of the nonsense you've been spouting.

All you've ever managed is a bunch of infantile insults and pseudoscientific nonsense. When asked to provide evidence to support your nonsense, you choose to just insult people instead. It shows the maturity of an 8th grade education, quite frankly.

Mr_Knight

The body can only burn fat when there is no glucose/glycogen available.

That statement is incorrect, and has been known to be incorrect for a long, long time. The body burns multiple fuels at the same time, and does not have to burn down glycogen to start burning fat.

Warchortle

People think it works better because they look leaner.. but this is an illusion because of how carbohydrates and water retention work.

EvgeniZyntx

That is the trouble with the internet.

People don't know what they don't know.

There is a difference between fat CELLS and the fat MOLECULES, called triclycerides that make up what is inside the fat cell.

The fat cell itself is a modified fibroblast.

If it does not contain any triglycerides, then it will be small. If has to serve as a storage depot for triglycerides, then it will swell to over fifty times it size.

The fat cells are a relative constant, though, as a said in a previous post, all cells are in a constant state of turnover. The turnover for fat cells may indeed be 10 percent a year. I would have to double check. Sounds reasonable.

But the turnover of the triclycerides, the total stored in the fat cells, are less than three months.

The triglycerides are constantly being broken down into glycerol and free fatty acids in a 1:3 ratio, transported back to the liver, reformulated, broken down again in the liver, released into the serum, and picked up by the adipose tissue cells, which repackage them as triglycerides and store them.

If the FFA and glycerol are needed for fuel, then the muscle cells will pick them and the total supply will drop.

Basic metabolism and physiology.

In Guyton's.

And all of this is in that book that you dismissed so smugly after reading the freebie ten pages on Kindle.

So, not to be petty, that is the problem here. People don't realize how complicated the human body is.

I am still concerned about your hostility.

Where does it come from?

What is your background?

You initially said fat Steve. Stop trying to move the goal posts. Fatty acids come from fat stores (fat cells).

I am a research scientist who gets very annoyed with someone pretending to have a science background who speaks with authority on subjects he knows nothing about.

Please address your misstep when you said that complete adipocyte turnover occurs every month.

In fact we KNOW this is untrue, because of studies done on DDT and how the body stores it in fat cells. And it is only when the fat is utilized by the body, that the toxin is released into the blood stream.

Not 3 weeks and not less than three months. Steve I continues to post whatever....

Let's see what the link I posted earlier actually says.

New research in the Sept. 25 online edition of the journal Nature shows that the turnover (storage and loss rate) of fat in the human body is about 1 1/2 years compared to fat cells, which turnover about every 10 years, according to Bruce Buchholz of Lawrence Livermore National Laboratory and one of the authors of the report. See the movie for a description.

And while the turnover rate of fat is on average 1 1/2 years for normal weight people, the news is worse for the obese -- the fat removal rate from fat tissue decreases and the amount of fat stored each year increases. In contrast, fat storage and removal rates balance in non-obese people for no net increase in fat.

"There is a slower output of fat in obese people in this study," Buchholz said. "The fat is on average 2 years old compared to 1 1/2 years."

The team, which included researchers from Karolinska University Hospital, University of Lyon, Uppsala University, University of Vienna, RIKEN Yokohama Institute, Technische Universit Munich, Churchill Hospital and the Karolinska Institute, applied carbon dating to fat content found within subcutaneous adipose tissue, the major fat depot for humans.

Carbon dating is typically used in archaeology and paleontology to date the age of artifacts. However, in this application, the scientists used the pulse of radiocarbon to analyze the age of fat and how fast it turns over in humans.

Radiocarbon or carbon-14 is naturally produced by cosmic ray interactions with air and is present at low levels in the atmosphere and food. Its concentration remained relatively constant during the past 4,000 years, but atmospheric testing of nuclear weapons from 1950-1963 produced a global pulse in the amount of radiocarbon in the atmosphere, Buchholz said.

Since the nuclear test ban treaty, the amount of carbon 14 in the atmosphere has decreased significantly. The carbon 14 diffuses out of the atmosphere and oxidizes to form carbon dioxide, which is taken up by plants. Since we eat plants or animals that live off of plants, the carbon 14 content in the atmosphere is directly mirrored in the human body.

Earlier research by Buchholz and colleagues at the Karolinska Institute showed that the number of fat cells in a human's body, whether lean or obese, is established during the teenage years. Changes in fat mass in adulthood can be attributed mainly to changes in fat cell volume, not an increase in the actual number of fat cells.

The new study found that fat, on average, is replaced six times during the life span of the 10-year fat cell, enabling a dynamic regulation of fat storage and movement over time.

"We found that a combination of high storage and low fat removal rates, as in obesity, facilitates fat accumulation within fatty tissue," Buchholz said. "This promotes the development or maintenance of excess body fat mass."

Nice effort, but I'll stand by Guyton's.

Triglycerides are in a constant state of synthesis, breakdown, and transport within the body. The fatty acid skeletons can survive, of course, and that is what this German group is measuring- the carbon 14 labeled skeletons, but they are constantly being repackaged into neutral triglycerides and shifted around. Fatty acids are not neutral fats, and that is what 95% percent of adipose tissue is by volume.

The labeled carbon itself in the fatty acid can only be gotten rid of if it is metabolized for energy and is blown off a carbon dioxide gas. In the liver, the labeled CO2 could be broken down and used in the synthesis of cholesterol, but if the person is in a positive calorie balance, this is not likely.

As I have said previously, there are all sorts of studies out there, and most are useless and a few fall apart when looked at closely.

The virtue of Guyton's, and why it is the the bible of physiology, is that all of these studies undergo rigorous peer review and testing, and only the stuff that holds up after that is included.

Now, if you can show me something in Guyton's that suggest a slower turnover rate of neutral triglycerides, then you might have something.

And I will change my opinion on anything if shown the evidence.

Let's continue this conversation because, well, there is a little science in it and if I expect you to actually have a scientific standard then I'm caught to maintain my own and adress this.

First off, Guyton's is an excellent resource. No doubt. I cut my teeth on it and it was my love and my stress in my junior year in college. It's an excellent texbook, so good, I've kept it all these years and passed my copy on to my daughter. But it is a textbook and not the sum knowledge of the universe. A good scientist does not listen to a single source, nor with total conviction refute other sources based on random statements about sourcing.
The reference I provided is a summary statement from a publication in Nature. Nature remains a premier peer-read and peer-reviewed articles. It is evidence. And yet you clearly fail to accept it.

Well, on to the science and evidence. And at this point it is less about responding to you but addressing some of the vague but interesting points this conversation has raised.

First off, let's talk about cell turnover and how its measured. It's actually very difficult to evaluate in the body the rate of cellular turnover because the usual technique was to take a biopsy sample and count cell turnover off of slides and then calculate rates versus surface/total cells or volumes. Archaic method that dates to at least Quekett in 1855. I even participated in software to automate the counting in the 90s. It's invasive and time consuming and not so accurate. So along the way we also have Coulter counters and other flow cytometry techniques, that count total cells in solution; molecular markers of proliferation, etc, etc... Anyway, cellular dating with C14 was a technique developped in the last 10 years which is quite interesting and relatively validated and a complement of molecular marking methods. It stands as one the references of cell dating and has been very useful in identifying where in the body we keep cells for a long time and where we do not.

(Let's toss in a reference: Cell. 2005 Jul 15;122(1):133-43.Retrospective birth dating of cells in humans.
Spalding KL, Bhardwaj RD, Buchholz BA, Druid H, Frisén J. - BTW that publication is "CELL" one of the top reference journals in the domain.

If you read the article (always useful) you'll note that the method there is valid for +- 1 or 2 years on tissue sample. Wait? What? That would not be very good for our discussion, in fact it would pretty much invalidate anything position I might have, right?
So let's look at the article you so cavalierly attacked as not evidence.

The source. Always the source.
http://www.ncbi.nlm.nih.gov/pubmed/18454136

Nature. 2008 Jun 5;453(7196):783-7. Dynamics of fat cell turnover in humans.

"To establish the dynamics within the stable population of adipocytes in adults, we have measured adipocyte turnover by analysing the integration of 14C derived from nuclear bomb tests in genomic DNA. Approximately 10% of fat cells are renewed annually at all adult ages and levels of body mass index."

So, that publication (in Nature) and referenced over 100 times in pubmed gives us a clear indicator that fat cell turnover is rather slow process. What it does show, if you go to the source, for turnover rate? The authors write: "We calculate a median turnover rate of 8.4% +- 6.2% (median+-average deviation) per yr, with half of the adipocytes replaced every 8.3 yr. That pretty clearly contradicts any statement you made of fat cells being replaced at an earlier period. And is also aligned with other research that you can read off of the orginal publication (here: http://www.adipofat.com/adipofat/pubs/nature06902.pdf)
If you have a specific page in Guyton that contradicts this please publish edition and page and we can compare sources.

Moving on to adipose lipid turnover.

Article in Nature.
Nature. 2011 Sep 25;478(7367):110-3. Dynamics of human adipose lipid turnover in health and metabolic disease.

Which I already cited. Your attempted refutation is based on the idea that the adipose tissue is being turned over at a faster rate but that triglyceride skeletons are somehow being kept. It's a nice conjecture, you'll have to reference it and tell me where what evidence you have that this is happening. Clearly the carbon markers are not selective and this would, if true, suggest that the actual turnover measured is even slower. Furthermore, possible issues of lipid pool turn over are adressed by the authors.

BTW - you didnt even bother to read the reference - they aren't German researchers - there is a German in the group.

But hey, science is a building structured by adding small pieces of research. Let's look at a non-C14 method of determining cell and triglyceride turnover.

More evidence and references!
Adipose tissue triglyceride turnover, de novo lipogenesis, and cell proliferation in humans measured with 2H2O
A. Strawford , F. Antelo , M. Christiansen , M. K. Hellerstein
American Journal of Physiology - Endocrinology and Metabolism Published 1 April 2004
(short resume here: http://ajpendo.physiology.org/content/286/4/E577.short)

These authors came up with a meaurement of cell turnover with a half life of "half-life 240-425 days" and adipose tissue triglyceride of "TG half-life 200-270 days" and a "Net lipolysis (TG turnover) was 50-60 g/day". Look, it even comes close to validating the work done with C14 decay measurements.

Voila, more evidence.

Now, I invite you to cite page and edition of Guyton's that contradicts this.

Edit: While you are at it, please also provide the methodology used for the measurement of month total lipid or gycol turnover and we can compare apples to apples. Ball is in your court.

tigersword

I need it explained in simple terms from those who swear by it. I feel like a moron but I really do not understand how you can lose faster than just a calories deficit and I am not talking about glycogen or water weight. My friend is doing it but is unable to explain how it work lol

Thank you

Hi - I've been low-carbing for a few months. I got some non-science type easy to understand info on healthy eating from web sites of zoe harcombe and jonathan bailor

para-phrasing from zoe harcombe for you (not plagiarism because I'm not claiming this stuff as my own!)

“…. exercise and BMR require quite different calories. Exercise is arguably best fuelled by carbohydrate (it provides glucose quickly for the body to use). BMR activities need fat, protein, vitamins and minerals. Carbohydrates can be useful for the vitamins and minerals they provide, but the macro nutrient, the carbohydrate itself, can only be used for energy – not cell repair and fighting infection …. it can’t be used for body maintenance – you need to burn if off down the gym or you will gain weight.
…. The body will always use carbohydrate for fuel first. Hence, if our average person has any glucose in the blood stream or any glycogen (stored glucose) in the body – this will be used to cover any gap in food eaten or activity done. The body can only burn fat when there is no glucose/glycogen available.”

"That’s a significant advantage for dieters and helps to explain the effectiveness of low carbohydrate diets."

See: http://www.zoeharcombe.com/the-knowledge/eating-less-will-not-make-us-weigh-less/
and http://thebailorgroup.com/

Both authors provide scientific references

I don't think of what I'm doing as low carb. It's more a nutrient dense diet. I'm swapping the starchy carbs and crappy fats for calories with non-starchy carbs - lots and lots and HEAPS of vegetables. and healthy fats. It's so much more food! I'm happy pigging out on low carb - and losing weight.

There are many things wrong with that statement. Mr. Knight mentioned one of them. Another one is the fact that carbs are not just used for energy. They are also used to regulate various hormones in the body, like growth hormone (more carbohydrates actually stimulate growth hormone release, higher fat actually inhibits growth hormone release.)

To say carbs are only for energy shows a complete lack of understanding on biology.

marcosgarciaacosta7

lowering carb intake isnt that bad. You can cycle your carb intake depending on your workout schedule. What is dangerous is lowering the amount of carbs to an extremely low amount. I do eat less carbs on my 2 rest days compared to my training days. Switching the types of carbs (from white to whole grain rice for example) can be a great substitute.

DamePiglet

Just a thought here:
a chit chat thread called "Ask Steve"

Steve, what do you think?

danimalkeys

Yanicka :flowerforyou:


The magic behind low carb is that you cut 1/3 of your macros and therefore naturally your calories go down which results in weight loss. It's just that, nothing less nothing more.

That's not true. You don't cut out 1/3 of your calories, you still target the same total calories per day. All you do is rearrange your macros to get most of your calories from good fat sources, adequate protein, and a targeted carb amount.

I don't know why it works, all I know is it has worked for me, giving me slow and steady weight loss. I was getting nowhere for months, losing the same 3-4lbs over and over eating 2300-2400 calories a day with 200+ grams of carbs. Counting and measuring everything. I couldn't get below 228lbs and sat around 232 most of the time.

I cut my carbs back to 50 and still ate the same 2300-2400, and the scale and tape measure started moving. The 1st 4-5lbs that come off right away is water weight, but 4 months in with and almost 20lbs lost, it's no longer water weight.

The only side effect I've had is my weightlifting has been impacted, but that would happen with any weight loss. Weights I could get 5 reps of at 232lbs I'm getting 2 reps of now. My energy level, mental alertness, all of that, is unchanged. The 1st week I had the "carb flu" but once I worked thru that, everything was cool.

tigersword

The fact that you're getting weaker shows your energy level IS impacted. Losing fat has almost no impact on strength, as anaerobic activity relies almost completely on carbohydrates (glucose/glycogen.)

Fat needs to be oxidized to be used for energy, and since the anaerobic system does not use oxygen, fat can't be used. The fat first has to be converted to glucose, which is a slow process. The body can't keep up with the demand of strength training, hence you get weaker and have less energy.

Add the carbs back in to the equation and your strength will build back up, even at your lower weight.

tmauck4472

It's worked for me....I find I crave almost no sweets anymore. I can take a bite of candy bar and put the rest down instead of eating two or three. So it's stopped my cravings. I try to eat very little complex carbs, but eat what I want of veggies and fruits. Your going to have to do your own research and take from it what you will and leave the rest go. Way to many opinions on the why's and how's and should and should not's. I made my decision to try it and I believe it's worked great for me. I really don't plan on ever going back to eating pasta's and such on a daily basis. But I still plan on enjoying it every now and then. But I can't tell you how it works I just know that for me it does.

AnninStPaul

For the same calories, you should have the same weight effects.

For me, though, when I eat carbs, I tend to crave more carbs, and then I crave even more carbs after that, and I end up eating a lot more. So for me, the point is not that it's low carb, but that it's high protein and fat. With protein and fat, I stay full, I don't get cravings, and I stay on my caloric target better.

^^THIS is why it works.

prettyface55

For the same calories, you should have the same weight effects.

For me, though, when I eat carbs, I tend to crave more carbs, and then I crave even more carbs after that, and I end up eating a lot more. So for me, the point is not that it's low carb, but that it's high protein and fat. With protein and fat, I stay full, I don't get cravings, and I stay on my caloric target better.

I feel the same way about this!:blushing:

danimalkeys

The fact that you're getting weaker shows your energy level IS impacted. Losing fat has almost no impact on strength, as anaerobic activity relies almost completely on carbohydrates (glucose/glycogen.)

Fat needs to be oxidized to be used for energy, and since the anaerobic system does not use oxygen, fat can't be used. The fat first has to be converted to glucose, which is a slow process. The body can't keep up with the demand of strength training, hence you get weaker and have less energy.

Add the carbs back in to the equation and your strength will build back up, even at your lower weight.

I'm talking about going from 5 reps to 2 reps of 250lbs on bench, and 4 reps of 360 on squats to 2 of 370 (which is probably close to a wash). I'm not becoming weak, just losing a couple reps on weight that is well over my bodyweight now, when before it was closer to my body weight. If I lost 20lbs on low carb and it resulted in me being unable to bench my body weight for 1 rep, when I was benching over my body weight before, or not being able to squat something like 315 when I was hitting 370 before, then I'd be concerned. Losing a couple reps with almost 20lbs of weight loss, I'm not concerned.

When I was powerlifting, I was smack in the middle of the 275lb weight class, usually going around 255lbs, so I never had to cut weight, but guys I knew who would cut to get down to a lower weight class always lost a few lbs, on their lifts, with bench press being the one affected the fastest.

Number_44

I feel like a moron but I really do not understand how you can lose faster than just a calories deficit and I am not talking about glycogen or water weight.

There isn't anything to understand - you can't.

Who said you could?

Number_44

For the same calories, you should have the same weight effects.

For me, though, when I eat carbs, I tend to crave more carbs, and then I crave even more carbs after that, and I end up eating a lot more. So for me, the point is not that it's low carb, but that it's high protein and fat. With protein and fat, I stay full, I don't get cravings, and I stay on my caloric target better.

^^THIS is why it works.

Heres the study for all the people who whine for them....

http://ajcn.nutrition.org/content/early/2013/06/26/ajcn.113.064113.abstract

suprzonic

I need it explained in simple terms from those who swear by it. I feel like a moron but I really do not understand how you can lose faster than just a calories deficit and I am not talking about glycogen or water weight. My friend is doing it but is unable to explain how it work lol

Thank you

Hi - I've been low-carbing for a few months. I got some non-science type easy to understand info on healthy eating from web sites of zoe harcombe and jonathan bailor

para-phrasing from zoe harcombe for you (not plagiarism because I'm not claiming this stuff as my own!)

“…. exercise and BMR require quite different calories. Exercise is arguably best fuelled by carbohydrate (it provides glucose quickly for the body to use). BMR activities need fat, protein, vitamins and minerals. Carbohydrates can be useful for the vitamins and minerals they provide, but the macro nutrient, the carbohydrate itself, can only be used for energy – not cell repair and fighting infection …. it can’t be used for body maintenance – you need to burn if off down the gym or you will gain weight.
…. The body will always use carbohydrate for fuel first. Hence, if our average person has any glucose in the blood stream or any glycogen (stored glucose) in the body – this will be used to cover any gap in food eaten or activity done. The body can only burn fat when there is no glucose/glycogen available.”

"That’s a significant advantage for dieters and helps to explain the effectiveness of low carbohydrate diets."

See: http://www.zoeharcombe.com/the-knowledge/eating-less-will-not-make-us-weigh-less/
and http://thebailorgroup.com/

Both authors provide scientific references

I don't think of what I'm doing as low carb. It's more a nutrient dense diet. I'm swapping the starchy carbs and crappy fats for calories with non-starchy carbs - lots and lots and HEAPS of vegetables. and healthy fats. It's so much more food! I'm happy pigging out on low carb - and losing weight.

There are many things wrong with that statement. Mr. Knight mentioned one of them. Another one is the fact that carbs are not just used for energy. They are also used to regulate various hormones in the body, like growth hormone (more carbohydrates actually stimulate growth hormone release, higher fat actually inhibits growth hormone release.)

To say carbs are only for energy shows a complete lack of understanding on biology.

Well I did say I was non-sciency;) and ya know - I really thought id worked it out. Back to the drawing.board.
,
I thought - after lots of reading (again - im not science-y inclined)! - I'd have more success with losing weight long term.focusing more on hormone balance. I read the reverse for HGH - that avoiding too many carbs will keep insulin levels low so that it cannot inhibit growth hormone from doing its work. Plus I thought glucose was an insulin antagonist. so then Off I.go.on my low carb keto adventures! ill stick to it. I actually like eating the way I am - which is a nice.change!

EvgeniZyntx

That is the trouble with the internet.

People don't know what they don't know.

There is a difference between fat CELLS and the fat MOLECULES, called triclycerides that make up what is inside the fat cell.

The fat cell itself is a modified fibroblast.

If it does not contain any triglycerides, then it will be small. If has to serve as a storage depot for triglycerides, then it will swell to over fifty times it size.

The fat cells are a relative constant, though, as a said in a previous post, all cells are in a constant state of turnover. The turnover for fat cells may indeed be 10 percent a year. I would have to double check. Sounds reasonable.

But the turnover of the triclycerides, the total stored in the fat cells, are less than three months.

The triglycerides are constantly being broken down into glycerol and free fatty acids in a 1:3 ratio, transported back to the liver, reformulated, broken down again in the liver, released into the serum, and picked up by the adipose tissue cells, which repackage them as triglycerides and store them.

If the FFA and glycerol are needed for fuel, then the muscle cells will pick them and the total supply will drop.

Basic metabolism and physiology.

In Guyton's.

And all of this is in that book that you dismissed so smugly after reading the freebie ten pages on Kindle.

So, not to be petty, that is the problem here. People don't realize how complicated the human body is.

I am still concerned about your hostility.

Where does it come from?

What is your background?

You initially said fat Steve. Stop trying to move the goal posts. Fatty acids come from fat stores (fat cells).

I am a research scientist who gets very annoyed with someone pretending to have a science background who speaks with authority on subjects he knows nothing about.

Please address your misstep when you said that complete adipocyte turnover occurs every month.

In fact we KNOW this is untrue, because of studies done on DDT and how the body stores it in fat cells. And it is only when the fat is utilized by the body, that the toxin is released into the blood stream.

Not 3 weeks and not less than three months. Steve I continues to post whatever....

Let's see what the link I posted earlier actually says.

New research in the Sept. 25 online edition of the journal Nature shows that the turnover (storage and loss rate) of fat in the human body is about 1 1/2 years compared to fat cells, which turnover about every 10 years, according to Bruce Buchholz of Lawrence Livermore National Laboratory and one of the authors of the report. See the movie for a description.

And while the turnover rate of fat is on average 1 1/2 years for normal weight people, the news is worse for the obese -- the fat removal rate from fat tissue decreases and the amount of fat stored each year increases. In contrast, fat storage and removal rates balance in non-obese people for no net increase in fat.

"There is a slower output of fat in obese people in this study," Buchholz said. "The fat is on average 2 years old compared to 1 1/2 years."

The team, which included researchers from Karolinska University Hospital, University of Lyon, Uppsala University, University of Vienna, RIKEN Yokohama Institute, Technische Universit Munich, Churchill Hospital and the Karolinska Institute, applied carbon dating to fat content found within subcutaneous adipose tissue, the major fat depot for humans.

Carbon dating is typically used in archaeology and paleontology to date the age of artifacts. However, in this application, the scientists used the pulse of radiocarbon to analyze the age of fat and how fast it turns over in humans.

Radiocarbon or carbon-14 is naturally produced by cosmic ray interactions with air and is present at low levels in the atmosphere and food. Its concentration remained relatively constant during the past 4,000 years, but atmospheric testing of nuclear weapons from 1950-1963 produced a global pulse in the amount of radiocarbon in the atmosphere, Buchholz said.

Since the nuclear test ban treaty, the amount of carbon 14 in the atmosphere has decreased significantly. The carbon 14 diffuses out of the atmosphere and oxidizes to form carbon dioxide, which is taken up by plants. Since we eat plants or animals that live off of plants, the carbon 14 content in the atmosphere is directly mirrored in the human body.

Earlier research by Buchholz and colleagues at the Karolinska Institute showed that the number of fat cells in a human's body, whether lean or obese, is established during the teenage years. Changes in fat mass in adulthood can be attributed mainly to changes in fat cell volume, not an increase in the actual number of fat cells.

The new study found that fat, on average, is replaced six times during the life span of the 10-year fat cell, enabling a dynamic regulation of fat storage and movement over time.

"We found that a combination of high storage and low fat removal rates, as in obesity, facilitates fat accumulation within fatty tissue," Buchholz said. "This promotes the development or maintenance of excess body fat mass."

Nice effort, but I'll stand by Guyton's.

Triglycerides are in a constant state of synthesis, breakdown, and transport within the body. The fatty acid skeletons can survive, of course, and that is what this German group is measuring- the carbon 14 labeled skeletons, but they are constantly being repackaged into neutral triglycerides and shifted around. Fatty acids are not neutral fats, and that is what 95% percent of adipose tissue is by volume.

The labeled carbon itself in the fatty acid can only be gotten rid of if it is metabolized for energy and is blown off a carbon dioxide gas. In the liver, the labeled CO2 could be broken down and used in the synthesis of cholesterol, but if the person is in a positive calorie balance, this is not likely.

As I have said previously, there are all sorts of studies out there, and most are useless and a few fall apart when looked at closely.

The virtue of Guyton's, and why it is the the bible of physiology, is that all of these studies undergo rigorous peer review and testing, and only the stuff that holds up after that is included.

Now, if you can show me something in Guyton's that suggest a slower turnover rate of neutral triglycerides, then you might have something.

And I will change my opinion on anything if shown the evidence.

Let's continue this conversation because, well, there is a little science in it and if I expect you to actually have a scientific standard then I'm caught to maintain my own and adress this.

First off, Guyton's is an excellent resource. No doubt. I cut my teeth on it and it was my love and my stress in my junior year in college. It's an excellent texbook, so good, I've kept it all these years and passed my copy on to my daughter. But it is a textbook and not the sum knowledge of the universe. A good scientist does not listen to a single source, nor with total conviction refute other sources based on random statements about sourcing.
The reference I provided is a summary statement from a publication in Nature. Nature remains a premier peer-read and peer-reviewed articles. It is evidence. And yet you clearly fail to accept it.

Well, on to the science and evidence. And at this point it is less about responding to you but addressing some of the vague but interesting points this conversation has raised.

First off, let's talk about cell turnover and how its measured. It's actually very difficult to evaluate in the body the rate of cellular turnover because the usual technique was to take a biopsy sample and count cell turnover off of slides and then calculate rates versus surface/total cells or volumes. Archaic method that dates to at least Quekett in 1855. I even participated in software to automate the counting in the 90s. It's invasive and time consuming and not so accurate. So along the way we also have Coulter counters and other flow cytometry techniques, that count total cells in solution; molecular markers of proliferation, etc, etc... Anyway, cellular dating with C14 was a technique developped in the last 10 years which is quite interesting and relatively validated and a complement of molecular marking methods. It stands as one the references of cell dating and has been very useful in identifying where in the body we keep cells for a long time and where we do not.

(Let's toss in a reference: Cell. 2005 Jul 15;122(1):133-43.Retrospective birth dating of cells in humans.
Spalding KL, Bhardwaj RD, Buchholz BA, Druid H, Frisén J. - BTW that publication is "CELL" one of the top reference journals in the domain.

If you read the article (always useful) you'll note that the method there is valid for +- 1 or 2 years on tissue sample. Wait? What? That would not be very good for our discussion, in fact it would pretty much invalidate anything position I might have, right?
So let's look at the article you so cavalierly attacked as not evidence.

The source. Always the source.
http://www.ncbi.nlm.nih.gov/pubmed/18454136

Nature. 2008 Jun 5;453(7196):783-7. Dynamics of fat cell turnover in humans.

"To establish the dynamics within the stable population of adipocytes in adults, we have measured adipocyte turnover by analysing the integration of 14C derived from nuclear bomb tests in genomic DNA. Approximately 10% of fat cells are renewed annually at all adult ages and levels of body mass index."

So, that publication (in Nature) and referenced over 100 times in pubmed gives us a clear indicator that fat cell turnover is rather slow process. What it does show, if you go to the source, for turnover rate? The authors write: "We calculate a median turnover rate of 8.4% +- 6.2% (median+-average deviation) per yr, with half of the adipocytes replaced every 8.3 yr. That pretty clearly contradicts any statement you made of fat cells being replaced at an earlier period. And is also aligned with other research that you can read off of the orginal publication (here: http://www.adipofat.com/adipofat/pubs/nature06902.pdf)
If you have a specific page in Guyton that contradicts this please publish edition and page and we can compare sources.

Moving on to adipose lipid turnover.

Article in Nature.
Nature. 2011 Sep 25;478(7367):110-3. Dynamics of human adipose lipid turnover in health and metabolic disease.

Which I already cited. Your attempted refutation is based on the idea that the adipose tissue is being turned over at a faster rate but that triglyceride skeletons are somehow being kept. It's a nice conjecture, you'll have to reference it and tell me where what evidence you have that this is happening. Clearly the carbon markers are not selective and this would, if true, suggest that the actual turnover measured is even slower. Furthermore, possible issues of lipid pool turn over are adressed by the authors.

BTW - you didnt even bother to read the reference - they aren't German researchers - there is a German in the group.

But hey, science is a building structured by adding small pieces of research. Let's look at a non-C14 method of determining cell and triglyceride turnover.

More evidence and references!
Adipose tissue triglyceride turnover, de novo lipogenesis, and cell proliferation in humans measured with 2H2O
A. Strawford , F. Antelo , M. Christiansen , M. K. Hellerstein
American Journal of Physiology - Endocrinology and Metabolism Published 1 April 2004
(short resume here: http://ajpendo.physiology.org/content/286/4/E577.short)

These authors came up with a meaurement of cell turnover with a half life of "half-life 240-425 days" and adipose tissue triglyceride of "TG half-life 200-270 days" and a "Net lipolysis (TG turnover) was 50-60 g/day". Look, it even comes close to validating the work done with C14 decay measurements.

Voila, more evidence.

Now, I invite you to cite page and edition of Guyton's that contradicts this.

Edit: While you are at it, please also provide the methodology used for the measurement of month total lipid or gycol turnover and we can compare apples to apples. Ball is in your court.

We are NOT talking about cell turnover.

This turnover is NOT about cells.

It is what the fat cell CONTAINS.

The fat cell contain NEUTRAL TRIGLYCERIDES.

These triglycerides are in a constant state of being broken down into glycerol and free fatty acids for transport back to the liver where they are resynthesized, broken down again, and transported in the serum where they are picked by the fat cells and resynthesized into neutral triglycerides.

That is the turnover I and Guyton's are talking about.

It is NOT the fat cells, it is WHAT the fat cells contain.

Go back and cut your wisdom teeth on Guyton's.

It is the gold standard and I am beginning to think that Guyton-bashing is a hallmark of ignorance.

Steve, steve, steve.

My post covers both cell and triglyceride/gylcerol turnover with references from peer reviewed articles. Glycerol turnover in adipose cells is specifically measured at "TG half-life 200-270 days" in the article cited.
I have never insulted or bashed Guyton - it's a great book, but not the sum knowledge.
I have asked you to reference a page (and edition) for your claims.

Again, please cite your page and edition. I'm beginning to think you haven't read Guyton and are just having fun here.