Metabolic Edge For Low Carbohydrate Diets: All Calories Are NOT Alike

[nobimbo]

Thermodynamic Edge For Low Carbohydrate Diets: SUNY Downstate Researchers Say All Calories Are NOT Alike

In a paper published in Nutrition Journal (Open Access, available without subscription at http://www.nutritionj.com/home), two researchers from SUNY Downstate Medical Center show that low carbohydrate, high protein diets can be expected to be more effective than low fat diets, going against long standing prejudice of the nutritional community, which has claimed that only calories count.

(PRWEB) July 31, 2004 -- “There are numerous examples of low carbohydrate diets being more effective than low fat diets with the same number of calories. It doesn’t always happen but it can happen,” said Dr. Richard Feinman of the Department of Biochemistry. “The nutritional establishment has been reluctant to accept this, because they say it violates the law of thermodynamics. However, they never seriously look at the thermodynamics, which not only says its possible, but it is to be expected.” he added.

In their paper, Dr. Feinman and Dr. Eugene J. Fine explain that thermodynamics is as much about efficiency as it is about energy conservation. Carbohydrate is an efficient fuel, whereas protein is not. On a low carbohydrate/high protein diet, even though total energy is conserved, more energy is wasted as heat, a process known as thermogenesis. This energy comes from burning fat.

The researchers stress that “the human body is not a storage locker. It is a machine and the efficiency of the machine is controlled by hormones and enzymes. Carbohydrates increase insulin and other hormones that regulate enzymes, leading to storage rather than burning of fat.”

“Of course, people are different” said the authors, “but many people are sensitive to the effects of carbohydrates and for them, a low carb diet is going to work well.”

The practical point is that getting rid of the idea that “a calorie is a calorie” opens the door for serious research into what kind of diets will be most effective and which people will benefit most. “This is important,” they explain “because millions of people
are seriously trying to lose weight on low carbohydrate diets, and instead of being given directions on the best way to do this, they have been largely discouraged by health professionals and self-appointed expert groups. The obesity epidemic is too important to allow this to happen.”

Note to editors/reporters: You can read the entire scientific paper by going to http://www.nutritionj.com/home and clicking on “Provisional PDF” at the bottom of the headline.

http://www.prweb.com/releases/2004/7/prweb145415.htm

[VALEWIS]

This article should be posted to every nutritionist/dietician and doctor on the planet. Lets hear it for Feinman and Fine!

Now lets hope they get on to researching fats as well in similar fashion, to look at how fatxcarb interaction is way different to fatxprotein interaction etc.

Val

[ceberezin]

The article comes from a journal put out by SUNY Downstate. Here's the link: http://zerlina.ingentaselect.com/vl=18395508/cl=16/nw=1/rpsv/cw/mal/15404196/v1n3/contp1-1.htm

By the way, I was under the impression that SUNY Downstate sponsored a conference on low carb science in June. Does anyone have any information on this?

[ItsTheWooo]

Wow, that has to be the best article relating to low carbohydrate diets that I've read in a long time. Two thumbs up ;).

[TheCaveman]

The fact that humans have hormones kind of screws up how easy it is to be a television nutritionist, eh?

[Samuel]

I agree we should be happy to find somebody in the medical community who feels this way. However, I still disagree with some of what they said.

In their paper, Dr. Feinman and Dr. Eugene J. Fine explain that thermodynamics is as much about efficiency as it is about energy conservation. Carbohydrate is an efficient fuel, whereas protein is not. On a low carbohydrate/high protein diet, even though total energy is conserved, more energy is wasted as heat, a process known as thermogenesis. This energy comes from burning fat.This is all correct except that the energy waste is in food which leaves the body before being fully metabolized through breath, sweat, urine and feces. Ketones which leaves the body through urine is an example. Temprature inside our body must be the same no matter which diet we are on.

[brobin]

Actually, your temperature varies by over a degree at different times of the day. It takes a fair bit of energy to keep your body even half a degree hotter then normal. You might not even feel it as your body can cope with this via the sweat function (which you only notice in the extreme).

I always get warn and even sweat when I eat my cheese for breakfast, especially after a workout.

On another note, I have often wondered why they are so upset about a calorie is just a calorie crap. It is obvious that our bodies are a machine. Thermodynamics is only concerned with the total energy being conserved. Everyone knows that certain engines burn fuel more efficiently. Everyone knows that some machines produce more waste energy then others. Why do nutritionists have such a difficult time with the concept that our bodies run less efficiently on protein, therefore we burn more fat and protein to do the same thing then if we ate carbs, an efficient fuel.

I am often amazed at just how stupid many scientists can be.... (and nutritionists.. LOL)

brobin

[mcsblues]

The article comes from a journal put out by SUNY Downstate. Here's the link: http://zerlina.ingentaselect.com/vl=18395508/cl=16/nw=1/rpsv/cw/mal/15404196/v1n3/contp1-1.htm

By the way, I was under the impression that SUNY Downstate sponsored a conference on low carb science in June. Does anyone have any information on this?

Yep, the Kingsbrook conference - Dr Feinman was one of the organizers. See this thread;

http://forum.lowcarber.org/showthread.php?t=193258&highlight=kingsbrook

You can email Dr Feinman and ask to be put on the mailing list for further material that this group of enlightened scientists is working on.

This paper also indicates Dr Feinman lives up to his name!;

"Title: Metabolic Syndrome and Low-Carbohydrate Ketogenic Diets in the Medical School Biochemistry Curriculum
Author(s): Richard D. Feinman PhD ; Mary Makowske PhD
Source: Metabolic Syndrome and Related Disorders Volume: 1 Number: 3 Page: 189 -- 197
DOI: 10.1089/154041903322716660
Publisher: Mary Ann Liebert, Inc.
Abstract: One of Robert Atkins contributions was to define a diet strategy in terms of an underlying metabolic principle ("the science behind Atkins"). The essential feature is that, by reducing insulin fluxes, lipids are funnelled away from storage and oxidized. Ketosis can be used as an indicator of lipolysis. A metabolic advantage is also proposed: controlled carbohydrates leads to greater weight loss per calorie than other diets. Although the Atkins diet and its scientific rationale are intended for a popular audience, the overall features are consistent with current metabolic ideas. We have used the Atkins controlled-carbohydrate diet as a focal point for teaching nutrition and metabolism in the first-year medical school curriculum. By presenting metabolism in the context of the current epidemic of obesity and of metabolic syndrome and related disorders, we provide direct application of the study of metabolic pathways, a subject not traditionally considered by medical students to be highly relevant to medical practice. We present here a summary of the metabolic basis of the Atkins diet as we teach it to medical students. We also discuss a proposed mechanism for metabolic advantage that is consistent with current ideas and that further brings out ideas in metabolism for students. The topics that are developed include the role of insulin and glucagon in lipolysis, control of lipoprotein lipase, the glucose-glycogen-gluconeogenesis interrelations, carbohydrate-protein interactions and ketosis. In essence, the approach is to expand the traditional feed-fast (post-absorptive) cycles to include the effect of low-carbohydrate meals: the disease states studied are generalized from traditional study of diabetes to include obesity and metabolic syndrome. The ideal diet for weight loss and treatment of metabolic syndrome, if it exists, remains to be determined, but presenting metabolism in the context of questions raised by the Atkins regimen prepares future physicians for critical analysis of clinical and basic metabolic information."

http://zerlina.ingentaselect.com/vl=19306930/cl=16/nw=1/rpsv/cw/mal/15404196/v1n3/s5/p189



Cheers,

Malcolm

[agd]

Well, I thought this was well known.

For every 100 calories of protein, you waste 30 of them. For every 100 calories of fat, you wast 3 of them. For every 100 calories of carbohydrates, you waste 10 of them.

The FDA recommends a 60/30/10 carb/fat/protein diet. On atkins, you might be 05/40/55.

.9*.6+.97*.3+.7*.1 = 0.901, i.e. you waste 10% of your cals
.9*.05+.97*.4+.7*.55 = .818, i.e. you waste 18% of your cals

So if my calculations are correct, on a 2000 kcal diet you burn 160 extra calories -- over the course of a year that adds up to 16 pounds!

Source: http://www.naturalphysiques.com/cms/index.php?itemid=99

[bluesmoke]

Actually the Atkins ratios are carbs/fat/protein of 10/65/25. As has been stated over and over again, it is not a high protein diet, it is a high fat diet. It is not true that fat burning is 97% efficient, the body uses as much as 50% of the energy in fats in conversion to usable fuel. Nyah Levi

[Nancy LC]

Where are you getting these numbers, Bluesmoke? I don't recall any percentages in any of the Atkins' books I read.

[ItsTheWooo]

There might be a slight metabolic advantage to eating fat & protein preferentially to carbs, but in my experience it isn't nearly as high as the figures you're estimating.

I've tracked my metabolic rate over several months, and my metabolism seems to be only average to slightly higher than what you would expect. Living a very sedentary lifestyle, at 135-125 pounds, and a 5'5 female, I burned about 1650 calories daily average (while consuming 1150). Eating maintenance raises this a little bit (100 cals tops), but generally speaking that metabolic rate is pretty average. I was eating like 15/30/55 carb/protein/fat. If I were wasting all this energy I think I would have had a faster metabolism.

Then again, I have lost 150 pounds. All studies say that those who lose that much weight typically have abnormally slow metabolisms afterward - 25% slower due to starvation response. Those of us who were very obese have more fat cells, and in order to become "thin" we have to shrink those fat cells to a size smaller than your average person. Even though we might have an average amount of fat, we have more fat cells so each cell contains relatively less fat in it. Each cell is very much "depleted" of fat and behaves similarly as if the whole individual had low body fat, even if the total amount of fat is adequate relative to "normal" individuals.

So, the fact that I have only a relatively normal metabolism despite the weight loss (rapid at that) might be a credit to low carb. If I were eating a "normal" diet, perhaps my metabolism would be much slower. Who knows.

[tholian8]

Then again, I have lost 150 pounds. All studies say that those who lose that much weight typically have abnormally slow metabolisms afterward - 25% slower due to starvation response.
Just curious...do you know if the metabolism ever bounces back, as a person goes on with their life at the new lower weight, or are you stuck with a slow metabolism for the rest of your life?

[Frederick]

or are you stuck with a slow metabolism for the rest of your life?

I sincerely hope this isn't the case....LOL

[Trinsdad]

Weight training and adding lean muscle goes a LONG way to building up your metabolism.

[dannysk]

" All studies say that those who lose that much weight typically have abnormally slow metabolisms afterward - 25% slower due to starvation response "
These studies, of course, are for those on a low-calorie (carb rich) diet. Every time you empty your clycogen stores, you begin to break down fat to ketones..BUT until you have enough ketones to run your body, you convert protein to glucose. If the diet does not include enough protein you break down muscle. This causes the slowing down of metabolism in a carb rich low calorie diet which refills and re-empties glycogen stores every day. Dr. Miriam Nelson of Tufts U. USDA school of nutrition spells this all out in "strong women stay slim". She claims that 21-25% of all weight lost on a diet (low cal carb rich) is really muscle... but she never quite got to low-carb.

brobin:
Nutritionists know all about effecient carbs, they have the mantra "carbs are the body's most effecient food". I must have read that at least 100 times. It is probably one of the reasons that low-carb became popular. That is when people realized what they were really saying.

danny

[brobin]

Dannysk.... LOL, you are correct. They love to tell you that carbs are so efficient and an easy fuel, then mock you when you suggest losing weight by eating low efficiency fuel.

But what do I know, apparently I am brain dead as I have not had my mandatory 130 grams of carbs a day to maintain brain function... ROFL...

Brobin

[catfishghj]

I believe that there is a metabolic advantage to fat and protien being less efficient fuels and I believe, based on things I have read, that the loss of ketones through breath and urine is a very minimal effect. But I thing these things are minor effects. This way of eating works mainly because you are not eating carbs which make you incredibly hungry.

[adkpam]

This means all carbs can be used for is fuel...they don't get used to rebuild cell membranes and muscle the way fat & protein do. Doesn't that give you a metabolic advantage right there? In terms of the fact that eating fat and protein are not only inefficient fuels, but some of it is diverted to body reconstruction off the top.

[JL53563]

This means all carbs can be used for is fuel...they don't get used to rebuild cell membranes and muscle the way fat & protein do. Doesn't that give you a metabolic advantage right there? In terms of the fact that eating fat and protein are not only inefficient fuels, but some of it is diverted to body reconstruction off the top.


Great point, adkpam. Why is it that otherwise intelligent people cannot see this?

[cc48510]

I suspect the numbers posted stating Fat was 97% Efficient are based on storage and a High-Carb Diet. I've seen it said quite often that Fat is the most efficiently stored fuel followed by Carbs and Protein [which is why they claim a diet should be Low in Fat and high in Carbs]...But, that's based on a typical High Carb Diet, and only comes into play when you eat too much. What it means is that if you eat a typical HC American Diet, that only 3% of your excess Fat Calories will be lost storing it as Body Fat versus 10% or more for Carbs and Protein.

But, that's only how efficiently its stored. What we're really concerned with is how efficiently its used as fuel and more importantly how the Macronutrient composition (LC vs. HC) effects that efficiency. Ketosis/Lipolysis is believed by many to be highly ineffcient in that fuel is outright wasted through sweat/urine/etc...A person on a typical HC Diet is not going to be in Ketosis/Lipolysis, but instead will be burning Carbs and storing extra Fat.

A person on a HC Diet will be using Carbs for energy and storing Fat for later use. Carbs are an efficient source of energy, and Fat is an efficient means of Storage. So, this is the optimal state to be in if you want to eat less, and gain weight. OTOH, when someone eats a LC Diet, they go into Ketosis/Lipolysis. In this state, they use Fat for fuel and generally store little or no new Fat. Fat is very inefficient when its actually used as fuel. Alot of it gets wasted.

Protein is not generally going to be used to an extensive degree for fuel. Some is needed to be converted to Glucose for those cells that can't use Ketones. But, most gets used to build new tissue, and for other needs that the body might have for it...and what is left over is not very easily converted and stored as fat, so Ketosis/Lipolysis is a very inefficient state, making it ideal for someone who wants to lose Weight/Fat.

[tamarian]

Press Release
Source: SUNY Downstate Medical Center

All Calories Are Not Created Equal

Friday August 13, 2:24 pm ET

Researchers Say Low-Carbohydrate Diets Have Metabolic Edge

NEW YORK, Aug. 13 /PRNewswire/ -- In a paper published last week in the Nutrition Journal, researchers from SUNY Downstate Medical Center show that low-carbohydrate, high-protein diets can be expected to be more effective for weight loss than low-fat diets. Their supposition goes against long standing prejudices of the nutritional community which for years have claimed that only calories count in the battle to lose weight."There are numerous examples of low-carbohydrate diets being more effective than low-fat diets with the same number of calories. It doesn't always happen but it can happen," said Dr. Richard Feinman of the Department of Biochemistry, SUNY. "The nutritional establishment has been reluctant to accept this, because they say it violates the laws of thermodynamics. However, they have not really looked seriously at thermodynamics. If they had, they would see that these results are possible, and according to the second law of thermodynamics, are also to be expected."

Feinman and Fine reviewed the existing literature on studies that compared low-carbohydrate and low-fat nutritional approaches. In doing so, they found a sufficient number of reports in the literature to establish the existence of a metabolic advantage. Clinical studies from such well-established research facilities as Duke and Harvard(1)(2), among others, were reviewed and analyzed. The researchers tabulated results from 10 studies, demonstrating that low-carbohydrate diets can lead to greater weight loss than isocaloric low-fat diets.

To explain this metabolic advantage, Dr. Feinman and Dr. Eugene J. Fine suggest that carbohydrates make an efficient fuel for the body, whereas protein does not.

"Your brain needs glucose to function properly," Feinman said. "There's no argument about that. Now, this glucose can come from dietary carbohydrates, but your body can make glucose from protein and, to a much lesser degree, from fat. However, the process of making glucose from protein is inefficient, and to get the extra energy needed, your body will burn the fat that it has already stored. I think that's the bottom line."

The researchers stress that the human body is not a storage locker. They compare it to a machine, and the efficiency of the machine is controlled by hormones and enzymes, which are impacted by nutrients. Carbohydrates increase insulin and other hormones that regulate enzymes which can lead to storing fat rather than burning fat.

"Of course, people are different" said Dr. Eugene Fine, a professor of nuclear medicine at Downstate and Jacobi Medical Center in the Bronx. "But many people are sensitive to the effects of carbohydrates and for them, a low- carbohydrate diet is going to work well."

The practical point is that getting rid of the idea that "a calorie is a calorie" opens the door for serious research into what kind of diets will be most effective and which people will benefit most.

"This is important," Feinman explain "because millions of people are seriously trying to lose weight on low-carbohydrate diets, and instead of being given directions on the best way to do this, they have been largely discouraged by health professionals and self-appointed expert groups. The obesity epidemic is too important to allow this to happen."

(1) Westman, E.C., Mavropoulos, J., Yancy, W.S., et al., "A Review of
Low-Carbohydrate Ketogenic Diets", Current Atherosclerosis Reports,
5(6), 2003, pages 476-483.

(2) Greene, P., Willett, W., Devecis, J., et al., "Pilot 12-Week Feeding
Weight-Loss Comparison: Low-Fat vs Low-Carbohydrate (Ketogenic)
Diets," Abstract Presented at The North American Association for the
Study of Obesity Annual Meeting 2003, Obesity Research, 11S, 2003,

http://biz.yahoo.com/prnews/040813/nyf088_1.html

Source: SUNY Downstate Medical Center

[JL53563]

Wow, it is very unusual to hear this kind of support for low carb eating. I hope this gets some attention from the media, although I fear it will not.

[CindySue48]

Good article. Thanks for posting

[VAgrrl]

Their supposition goes against long standing prejudices of the nutritional community which for years have claimed that only calories count in the battle to lose weight.

"prejudices" is right!

"This is important," Feinman explain "because millions of people are seriously trying to lose weight on low-carbohydrate diets, and instead of being given directions on the best way to do this, they have been largely discouraged by health professionals and self-appointed expert groups. The obesity epidemic is too important to allow this to happen."

I just breathed a big sigh of relief when I read that--it's like Finally!!

thanks for the article

[ewert]

"Protein is not generally going to be used to an extensive degree for fuel. Some is needed to be converted to Glucose for those cells that can't use Ketones. But, most gets used to build new tissue, and for other needs that the body might have for it...and what is left over is not very easily converted and stored as fat, so Ketosis/Lipolysis is a very inefficient state, making it ideal for someone who wants to lose Weight/Fat."

Technically (if one can say that about the human body), one doesn't need to use protein based gluconeogenesis to get the required glucose for operating anaerobic cells. Reforming anaerobically burned glucose back into glucose means all anaerobic energy can be "recycled" "infinitely" (not exactly, but you get my drift). The glucose that gets burned can be formed from the glyserol-base of fat burned for energy. According to one biochemistry text, the numbers came down to 19grams from fat glyserol and 16grams of glucose burned, so given a bit of leeway I'd say that comes suspiciously close to being evolutionarily purposeful: barring refueling after anaerobic bursts of excersice, the human body is totally fuelable by fat.

Go fat! Fat rules! :P

[ceberezin]

Nutritionists know all about effecient carbs, they have the mantra "carbs are the body's most effecient food".
When nutritionists tell you to eat carbs because they are burned efficiently, they are assuming a particular logic to the body. Naturally, in their assumption, the body wants to burn the most efficient fuel, as any machine would. But there are other logics. The body is not a machine. It makes more sense to say that the body burns carbs before fat because it wants to get rid of them as quickly as possible before they can damage tissues through glycation.

[woodpecker]

I find that walking a mile or two a day for a month speeds up my metabolism and this effect will last for about 6 months with no further exercise. I usually do this in the summer and then in February - I start to put the weight on again.

[sb24u]

if it is true and real..it will be proven to be so.....great and important article....




Thermodynamic Edge For Low Carbohydrate Diets: SUNY Downstate Researchers Say All Calories Are NOT Alike

In a paper published in Nutrition Journal (Open Access, available without subscription at http://www.nutritionj.com/home), two researchers from SUNY Downstate Medical Center show that low carbohydrate, high protein diets can be expected to be more effective than low fat diets, going against long standing prejudice of the nutritional community, which has claimed that only calories count.

(PRWEB) July 31, 2004 -- “There are numerous examples of low carbohydrate diets being more effective than low fat diets with the same number of calories. It doesn’t always happen but it can happen,” said Dr. Richard Feinman of the Department of Biochemistry. “The nutritional establishment has been reluctant to accept this, because they say it violates the law of thermodynamics. However, they never seriously look at the thermodynamics, which not only says its possible, but it is to be expected.” he added.

In their paper, Dr. Feinman and Dr. Eugene J. Fine explain that thermodynamics is as much about efficiency as it is about energy conservation. Carbohydrate is an efficient fuel, whereas protein is not. On a low carbohydrate/high protein diet, even though total energy is conserved, more energy is wasted as heat, a process known as thermogenesis. This energy comes from burning fat.

The researchers stress that “the human body is not a storage locker. It is a machine and the efficiency of the machine is controlled by hormones and enzymes. Carbohydrates increase insulin and other hormones that regulate enzymes, leading to storage rather than burning of fat.”

“Of course, people are different” said the authors, “but many people are sensitive to the effects of carbohydrates and for them, a low carb diet is going to work well.”

The practical point is that getting rid of the idea that “a calorie is a calorie” opens the door for serious research into what kind of diets will be most effective and which people will benefit most. “This is important,” they explain “because millions of people
are seriously trying to lose weight on low carbohydrate diets, and instead of being given directions on the best way to do this, they have been largely discouraged by health professionals and self-appointed expert groups. The obesity epidemic is too important to allow this to happen.”

Note to editors/reporters: You can read the entire scientific paper by going to http://www.nutritionj.com/home and clicking on “Provisional PDF” at the bottom of the headline.

http://www.prweb.com/releases/2004/7/prweb145415.htm

[cc48510]

I did some searching, and it appears that once various fuels are actually metabolized, the percentage of available released is similar for both Fat and Carbs (about half.) But, the real issue is not what percentage is released, but what is wasted and how the energy is used. A "High Protein/Low Carb" diet is believed to be less efficient by some because it releases more energy as heat than a High Carb Diet. One other theory is that when ketone levels begin to rise too high, the body has to excrete them to keep its pH within an acceptable range. Thus, the body excretes fuels (Ketones) unused.

Unless you're a Diabetic, you don't excrete Glucose unused. Glucose is very efficient in that manner. If its not used its either converted back to Glucose/Glycogen, or converted to Fat, and stored on the body. Even in an Anaerobic Metabolism, when Glucose yields very little ATP (Energy) per unit of Glucose, it produces a byproduct (Lactate,) which the body can further Metabolized to get more ATP (Energy.) Lactate can also be converted back to Glucose [with very little loss of Energy] later on, and used again.

http://web.indstate.edu/thcme/mwking/amino-acid-metabolism.html

Protein is unique in that depending on the Amino Acid composition, it may be metabolized more like Carbs or more like Fat. Amino Acids come in 3 types: Ketogenic, Glucogenic, and Keto/Glucogenic. In some instances, Amino Acids can be directly metabolized for energy.

The Ketogenic Amino Acids (Lysine and Leucine) CANNOT be converted the Glucose. They are metabolized to Acetyl CoA, the same stuff Fatty Acids are Metabolized to. From there, they are metabolized the same as Fatty Acids, including the possibility of being converted to Ketone Bodies.

The Keto/Glucogenic Amino Acids (Isoleucine, Phenylalanine, Threonine, Tryptophan, and Tyrosine) can be metabolized to either Acetyl CoA, Pyruvate, TCA Intermediates, or a combination thereof. Pyruvate and TCA Intermediates can be either metabolized for energy or converted to Glucose via Glucogenesis.

The Glucogenic Amino Acids (Glutamate, Aspartate, Alanine, Ornithine, Proline, Serine, Cysteine, Methionine, and Glycine) CANNOT be directly metabolized to Acetyl CoA, and thus don't yield Ketone Bodies. They are metabolized to Pyruvate or TCA Intermediates, which may be metabolized for energy or converted to Glucose.

[fatburner]

I did some searching, and it appears that once various fuels are actually metabolized, the percentage of available released is similar for both Fat and Carbs (about half.) But, the real issue is not what percentage is released, but what is wasted and how the energy is used. A "High Protein/Low Carb" diet is believed to be less efficient by some because it releases more energy as heat than a High Carb Diet. One other theory is that when ketone levels begin to rise too high, the body has to excrete them to keep its pH within an acceptable range. Thus, the body excretes fuels (Ketones) unused.

Unless you're a Diabetic, you don't excrete Glucose unused. Glucose is very efficient in that manner. If its not used its either converted back to Glucose/Glycogen, or converted to Fat, and stored on the body. Even in an Anaerobic Metabolism, when Glucose yields very little ATP (Energy) per unit of Glucose, it produces a byproduct (Lactate,) which the body can further Metabolized to get more ATP (Energy.) Lactate can also be converted back to Glucose [with very little loss of Energy] later on, and used again.

http://web.indstate.edu/thcme/mwking/amino-acid-metabolism.html

Protein is unique in that depending on the Amino Acid composition, it may be metabolized more like Carbs or more like Fat. Amino Acids come in 3 types: Ketogenic, Glucogenic, and Keto/Glucogenic. In some instances, Amino Acids can be directly metabolized for energy.

The Ketogenic Amino Acids (Lysine and Leucine) CANNOT be converted the Glucose. They are metabolized to Acetyl CoA, the same stuff Fatty Acids are Metabolized to. From there, they are metabolized the same as Fatty Acids, including the possibility of being converted to Ketone Bodies.

The Keto/Glucogenic Amino Acids (Isoleucine, Phenylalanine, Threonine, Tryptophan, and Tyrosine) can be metabolized to either Acetyl CoA, Pyruvate, TCA Intermediates, or a combination thereof. Pyruvate and TCA Intermediates can be either metabolized for energy or converted to Glucose via Glucogenesis.

The Glucogenic Amino Acids (Glutamate, Aspartate, Alanine, Ornithine, Proline, Serine, Cysteine, Methionine, and Glycine) CANNOT be directly metabolized to Acetyl CoA, and thus don't yield Ketone Bodies. They are metabolized to Pyruvate or TCA Intermediates, which may be metabolized for energy or converted to Glucose.


Fascinating! But I'm still not really clear wether using fatty acids directly in the mitochondria as acetyl Co A is a separate process and energy pathway to ketosis. That is, can you be using FFA's directly in the mitochondria of most cells for energy without a ketone in sight or are ketones a necessary part of energy production from fat. Note that I'm not talking about the mobilization of body fat stores by glucagon into FFA's which can then be available for energy. So the FFA's can be either dietary or bodyfat (or both ;) ), but are ketones a necessary part of them being utilized for energy, or just one such way. I've never had bodyweight issues, and I've never been in measurable ketosis but I've been on induction carb levels (for optimum health reasons) and very high fat/ moderate protein for over two years. So what's actually happening in my mitochondria. Are ketones necessarily involved. I realize a few kinds of tissue need (some) ketones if glucose is not available - brain for instance. But what about the rest?
Help! I really want to understand this.
Confused

[cc48510]

Fascinating! But I'm still not really clear wether using fatty acids directly in the mitochondria as acetyl Co A is a separate process and energy pathway to ketosis. That is, can you be using FFA's directly in the mitochondria of most cells for energy without a ketone in sight or are ketones a necessary part of energy production from fat. Note that I'm not talking about the mobilization of body fat stores by glucagon into FFA's which can then be available for energy. So the FFA's can be either dietary or bodyfat (or both ;) ), but are ketones a necessary part of them being utilized for energy, or just one such way. I've never had bodyweight issues, and I've never been in measurable ketosis but I've been on induction carb levels (for optimum health reasons) and very high fat/ moderate protein for over two years. So what's actually happening in my mitochondria. Are ketones necessarily involved. I realize a few kinds of tissue need (some) ketones if glucose is not available - brain for instance. But what about the rest?
Help! I really want to understand this.
Confused

My understanding is that fat can be metabolized directly in the Mitochondria, without first converting it to Ketones...and that ketones are created only in specific situations (to feed the Brain, when there is inadaquete oxalacetate, when too much fat is being burned too quickly, etc...)

http://www.unisanet.unisa.edu.au/08366/h%26p2fuel.htm

Fatty acids are mobilised from triglyceride stores and used for ATP production, either directly or via the formation of the water soluble ketone bodies.

http://www.unisanet.unisa.edu.au/08366/timages/aerobf2.gif

http://www.unisanet.unisa.edu.au/08366/h%26p2fat.htm

An alternative method of utilising the acetyl CoA formed by ß-oxidation is via the synthesis and subsequent oxidation of four-carbon units known collectively as ketone bodies.

Acetyl CoA is converted in the liver into acetoacetate (essentially two acetyl groups covalently linked). Acetoacetate can be further reduced to form ß-hydroxybutyrate. These two compounds are referred to as ketone bodies. Their synthesis occurs in the liver.

They diffuse from the liver into the circulation and are used as fuels by several tissues. Heart muscle and renal cortex, in particular, use acetoacetate in preference to glucose. In contrast, glucose is the major fuel for the brain and erythrocytes in a human on a balanced diet. The brain has the capacity to adapt to the use of acetoacetate during starvation (and in the metabolic disease diabetes mellitus). In starvation of long standing, acetoacetate meets more than 70% of the energy needs of the brain.

This ability of the brain to adapt to the use of acetoacetate is important because fatty acids cannot enter neural tissue. Acetoacetate is regarded as a water soluble and readily transported form of acetyl CoA.

[fatburner]

[QUOTE=cc48510]My understanding is that fat can be metabolized directly in the Mitochondria, without first converting it to Ketones...and that ketones are created only in specific situations (to feed the Brain, when there is inadaquete oxalacetate, when too much fat is being burned too quickly, etc...[QUOTE].

Many thanks. That cleared it up for me. I was always a bit puzzled by the oft stated assumption that very low levels of carbs would necessitate constant high use of ketones ( rather than just a trickle to keep the brain purring). It was amusing to read one of your quoted biochem texts describing the low carb state of the brain becoming adapted to using mostly ketones as 'long term starvation' . I have never felt as if I was starving! . Hmmmm? can I be bothered going to the fridge for another helping of chocolate mousse(.3g cho/ serve :p ) ?
One other question. I can see how using ketones is a very energy inefficient (desirably so for weightloss) process. But once your mitochondria get accustomed to FFA metabolism (ie. fat metabolism without ketones)- even during intense exercise (my endurance and strength is far superior now to when I was High complex carb/protein, and I never 'refeed' ) it's actually a very efficient process isn't it? Which might explain why people with a lot of weight to lose find it more and more difficult to do so, the longer they spend low carbing. I'm sure it's still the healthiest and the easiest way to do so (particularly because you just don't get the artificial insulin related 'carb hunger') but would be quicker if the 'metabolic edge' did not reduce the longer a person spent low carbing.

[cc48510]

One other question. I can see how using ketones is a very energy inefficient (desirably so for weightloss) process. But once your mitochondria get accustomed to FFA metabolism (ie. fat metabolism without ketones)- even during intense exercise (my endurance and strength is far superior now to when I was High complex carb/protein, and I never 'refeed' ) it's actually a very efficient process isn't it? Which might explain why people with a lot of weight to lose find it more and more difficult to do so, the longer they spend low carbing. I'm sure it's still the healthiest and the easiest way to do so (particularly because you just don't get the artificial insulin related 'carb hunger') but would be quicker if the 'metabolic edge' did not reduce the longer a person spent low carbing.

At least from my personal experience, that seems to be somewhat true. My weight loss slowed down considerably (3.5 lbs/wk to 1-2 lbs/wk) almost overnight when the strips stopped turning. Since then, its slowed down to about 1/2 lb/wk, but that was far more gradual.

[brobin]

Keep in mind that as you lose weight, your body need far fewer calories, so as you approach your goal, you will lose weight slower. At some point, if you don't adjust your calories, you will stall. That is pretty typical on any diet. People get use to eating a certain amount of food and forget to slowly adjust downwards.

In my case, I had to cut out a snack and ramp up the exercise to lose those last 15 pounds. However, once you finally lose all the weight, you can ramp up a bit in your eating to maintenance levels.

At 9 pounds from your goal, I am not surprised you are down to 0.5 pounds per week. Keep in mind though that that is the best way to go for the last 10 anyway!

Brobin

[notsweet]

all I have to say is that continued studies in the area of nutrition will only continue to support what others have been saying for centuries about the benefits of a low and lower carb intake in a person's daily diet....it all will begin to be more cohesive and make all the sense in the world as time goes on...I am glad this study came out....facts always always speak for themselves

[msundi83]

I am excited because there is a lot of research in low carb dieting going on. Believe it or not many researchers are interested in this style now even if they may not be convinced it is benificial to people. The one thing I would like to see changed in all these studies is the variable for measuring effectiveness...weight.

As you all know, when starting a low carb regimine you will drop a lot of water weight initially and dieters eating the same calories on a low carb diet will hold less water than if they were eating a more mixed carb diet. Measuring weight only leads to the counter point that these dieters would just gain the weight back if they started eating "normally" again. A bad argument for several reasons yes, but still annoying.

In all studies like this (testing low carb diets and other means of improving body comp) we need to make body comp testing the standard. Underwater bodyfat testing is becoming more and more available and utilizing such measures before and after these studies would be very prudent. We need to show if body comp is improved on LC relative to MC/HC diets. It is my guess, and I'm sure others, that besides the dryer look and feel a LC diet gives, there is a better fat reduction effect of LC dieting.

[VALEWIS]

In all studies like this (testing low carb diets and other means of improving body comp) we need to make body comp testing the standard. Underwater bodyfat testing is becoming more and more available and utilizing such measures before and after these studies would be very prudent. We need to show if body comp is improved on LC relative to MC/HC diets. It is my guess, and I'm sure others, that besides the dryer look and feel a LC diet gives, there is a better fat reduction effect of LC dieting.

I agree. The protein sparing diets are all very low carb..the key is to keep the protein macro high and the calories low for the best body composition re losing fat vs losing LBM while losing 'weight.'

[xtronics]

The amount of calories isn't as important as the amount of hunger: Carbs stimulate a large insulin response. Insulin is a growth factor for adipose(fat) tissue. The result is, insulin makes you quite hungry (they give insulin to treat anorexia.)

[Turtle2003]

How do you go about tracking your metabolism? I thought measuring your metabolism was something that could only be done in a lab. Not so?

[LC FP]

Reading through this thread makes me realize that this board used to know a lot more about metabolism than it currently does.

[Frederick]

Nice reading this thread again.

[Beth1708]

Temprature inside our body must be the same no matter which diet we are on.

FWIW, my temperature tends to run between 96 and 97 deg F, at least in the morning when I measure it. Assuming I'm not a completely weird case & that I'm also healthy (the latter, at least, seems to be so), it follows that different people have different temperatures. This wasn't always true, my temp used to be in the standard 98.6 range, but it dropped some years ago, I don't know why.

Beth

[kneebrace]

Reading through this thread makes me realize that this board used to know a lot more about metabolism than it currently does.

That struck me too LC.

Stuart

[Lisa N]

FWIW, my temperature tends to run between 96 and 97 deg F, at least in the morning when I measure it. Assuming I'm not a completely weird case & that I'm also healthy (the latter, at least, seems to be so), it follows that different people have different temperatures. This wasn't always true, my temp used to be in the standard 98.6 range, but it dropped some years ago, I don't know why.

Beth

A low basal temperature (first thing in the morning) could indicate hypothyroid. :idea:

[Beth1708]

can I be bothered going to the fridge for another helping of chocolate mousse(.3g cho/ serve :p ) ?


Can you point me to the recipe? :-)

[Beth1708]

A low basal temperature (first thing in the morning) could indicate hypothyroid. :idea:

Yes, my doctor says that my TSH is a little high, but not so much that she has suggested medicine. I've read through the symptoms of hypothyroid & the only one I have is a low temp. I don't feel cold (in fact, I used to be cold often & aren't anymore). It doesn't strike me as a problem, just the way my body is.

Beth