Digestion Times For RAF

[Sully]

Anyone know the digestion times of various raw animal meats & Eggs? Thanks!

[Sully]

???anyone???

[boxcarguy07]

Wouldn't it largely depend on one's individual system?

[Sully]

Wouldn't it largely depend on one's individual system?

yeah i thought of that, but I'm just wondering what the average might be...ya know, approximately

[Sully]

What digest quicker?...raw nuts, or raw meat???

[mors01]

In my experience, raw meat digests much faster than raw nuts (even if soaked/sprouted).

[William]

IIRC according to Aajonus Vonderplanitz, raw meat is digested in one hour.

[Sully]

IIRC according to Aajonus Vonderplanitz, raw meat is digested in one hour.

yes i thougt nuts were slower

[boxcarguy07]

If raw meat is supposed to be fully digested in one hour, then I'm in big trouble.
Somehow I don't think that is right at all.

[wodgina]

1 hour seems a bit quick and AV is prone to exaggeration. Maybe a couple of hours but raw meat takes less energy so you don't crash out after eating dinner like with a cooked diet.

[lex_rooker]

One thing I can tell you is that a meal of meat and fat will cause a slow rise in BG over about a 3 hour period after which it starts a slow decline.  I'm sure that the 3 hours is a combination of digestion of the meal as well as the time it takes for a portion of the resulting amino acids to be converted by the liver into BG, but I expect that it is fairly representative of the overall time to metabolize a meat/fat meal.

Carbs on the other hand, can cause a massive rise in BG within 15 minutes, especially if the carbs are free simple sugars rather than complex carbs that must be released from indigestible fiber.  There are even some carbs that require intestinal flora to break down the fiber to release the digestible portion within and this can take many hours (not to mention causing great discomfort in the form of gas etc.). Beans and legumes anyone?

Based on the rise and fall of BG, the digestion time for a meal consisting of meat and fat alone is quite consistent, but a meal of mixed carbohydrate sources appears to be quite variable depending on the source. 

Lex

[Sully]

what is bg?, blood and glucose?

[Raw Kyle]

what is bg?, blood and glucose?

It's "blood glucose."

As for nut digestion time vs. meat, nuts definitely take longer. Imo nuts take longer to digest than even cooked food. They are the most concentrated and hard to digest food in the world, the nutrition for a tree to grow is in there and at the same time it's locked down by shell coverings and enzyme inhibitors.

[JustAnotherExplorer]

The only study that I'm aware of that comes anywhere close to addressing this question is one where they fed four pythons identical amounts of beef, one raw, one cooked, one raw and ground, one cooked and ground.  They came to the conclusion that it took less time and energy to consume the meat when it was cooked or ground than when it was raw with even greater reductions when the meat was ground and cooked.
http://lib.bioinfo.pl/pmid:17827047

How applicable this information is to humans is anybody's guess, as is the question of which snake received the most nutritive benefit.

[TylerDurden]

The only study that I'm aware of that comes anywhere close to addressing this question is one where they fed four pythons identical amounts of beef, one raw, one cooked, one raw and ground, one cooked and ground.  They came to the conclusion that it took less time and energy to consume the meat when it was cooked or ground than when it was raw with even greater reductions when the meat was ground and cooked.
http://lib.bioinfo.pl/pmid:17827047

How applicable this information is to humans is anybody's guess, as is the question of which snake received the most nutritive benefit.

The above study was made by Wrangham, as I recall, who is a notoriously biased,anti-raw chimp behaviourist, and the study has not been corroborated by any other studies.Wrangham's claims re cooked-food leading to bigger brains and his laughable claim that no human can survive for long on a  raw food diet, even one including mostly raw meats,shows that he's never once met any Raw Animal Foodist at all. Plus his claim re humans needing to chew raw meats  for 5 to 6 hours a day in order to get adequate nutrition is not only absurdly extreme but based on a ridiculous comparison to chimpanzees(who are an entirely different species and who are not as adapted to meat-eating as humans are):-

http://www.rawpaleodiet.com/advent-of-cooking-article/

Here's 2 scientific studies which prove Wrangham dead-wrong and show that raw meat is actually easier to digest:-

http://www.ncbi.nlm.nih.gov/pubmed/1897402

http://www.ncbi.nlm.nih.gov/pubmed/3748129

Anyway, Wrangham's pro-cooking views are held in ridicule by most palaeoanthroplogists as he continually makes the same mistake of many amteur scientists:- he makes up a really nice-sounding theory and then looks around for anything whatsoever, no matter how dodgy, to back it up. Real science works by starting with the facts/details of experiments  and only then forming a theory from it, rather than the other way round. Well, it's just as well we have someonas dodgy as Wrangham as the main anti-raw proponent, I suppose.


http://www.rawpaleodiet.com/advent-of-cooking-article/

[JustAnotherExplorer]

Wrangham was one of the authors of the study, but another collaborator was Stephen Secor whose main focus of research has been the digestive system of pythons http://lib.bioinfo.pl/auth:Secor,SM.  Because of this I see no reason to doubt the accuracy of the descriptions of times and energy levels of python digestion.  The extrapolation to humans at the beginning of the abstract is a lot dodgier, but all of us who've made it this far into the world of interpreting and digesting (pun intended) research should be familiar with how fast and loose many authors are with inserting opinions and conclusions into abstracts that have absolutely nothing to do with the data presented in the paper (e.g. many studies that purport to vilify cholesterol and Saturated fat).  I see no reason why snakes can't digest cooked meat more easily than raw while it being the reverse for humans.

I have not read the full studies that you linked to, just the abstracts, but the first one seems to indicate that many plant foods are more easily digestible when cooked (hmm, should we be eating raw meat and cooked plants?) and the only reference to protein digestibility refers to "excessive heat."  Without referring to the body of the study I can't know exactly what temperature "excessive heat" refers to or if the damage caused increases linearly or exponentially as temperatures are raised.  I don't want to make any assumptions, but based just on this info it is equally as likely that low temperature cooking is beneficial or neutral as it is harmful.

From the second study, I'm really not sure what Volatile Ammonium Bases are or what affect they have on digestion, if any.  From a Google search it also appears that these substances have only been measured in fish, not land animals, so the study doesn't necessarily have any bearing whatsoever on the cooking of terrestrial meat.  Without knowing what effect VAB's actually have on the human body or digestion of fish I can't say that this study gives us any information on the human digestion of cooked seafood either.  Also, the study found similar changes in the fish not only from cooking but from freezing and storing.  The freezing and storing is exactly what the Inuit would do, so saying that a change caused by cooking is bad when the same change caused by freezing and storing is neutral or good seems untenable to me.

[TylerDurden]

Freezing or storing food doesn't do anywhere near as much damage as heat. You have to freeze/store for absolutely ages before the damage becomes similiar(see beyondveg.com 's ridiculous anti-raw "thesis" where 30 days' storage is cited etc.). As regards the study re pythons, anyone can make up statistics for a particular study, making the facts fit the theories one wants.

As regards the Oste study, it makes it clear that heating above 100 degrees Centigrade decreases meat-digestibility. As regards heating above 40 degrees Celsius, when enzymes, and eventually, bacteria, start getting destroyed, it would be pretty difficult to argue that there wasn't a linear rate of harm done to food via heating. I mean, surely well-charred meat)with a proven higher amount of toxins in them, such as PAHs, would be far less digestible by comparison to lightly-cooked- or raw-foods?

And, of course, Wrangham totally ignores the whole issue of toxins in cooked-foods, which is a most inconvenient subject for him.

Obviously, more scientific data is needed, but it's becoming more and more difficult to defend cooked-diets when pet-owners find that their pets digest raw meats(on a prey-model diet) far better than the cooked-scraps or processed nutritional supplements they got before. And, brilliantly, all those vets who warned against the supposed "dangers of raw diets" are now looking very stupid, indeed, in the wake of all those recent Chinese pet-food-contamination-scares.

As regards the issue of vegetables being supposedly  "improved" by cooking re removing antinutrients, this is a moot point. Many nutritionists claim that small amounts of such raw vegetables contain "phytonutrients"  which, in small amounts, are beneficial, whereas they would be harmful in much larger amounts(and called "antinutrients", then). Plus, of course, cooking creates toxins in vegetables such as AGEs(advanced glycation endproducts), thus making cooked-veg worse than raw veg, overall.

In any case, the whole python-issue is killed off by the famous , more definitive Pottenger study which(along with numerous anecdotal reports from raw-feeding pet-owners) showed that cats fed on cooked diets suffer from numerous health-problems, which worsen over the generations. The only argument that anti-rawists can convincingly come up with against this study is that "adding artificial taurine supplements" to cooked-pet-food made everything (supposedly) OK - what they can't argue is that heat destroys taurine, which is essential for cats -  so only artificially-supplemented cooked-diets can even compete(albeit with serious damage for cats in the long-term, via AGEs, HCAs etc.).

[JustAnotherExplorer]

I agree that cats are a closer surrogate to humans than snakes are, but, AFAIK, the Pottenger studies tell us nothing about the amount of time that it takes for food to be digested and so both studies provide us with useful information.

Wrangham's name is on the python paper but I have no clue how much work he actually did on the project.  It is very common in academia for supervisors who have done no or little work to have their names put on papers above their subordinates.  I do not know if that is what happened in this case or not.  How is it that you are aware that he was "intimately involved?"  If you're basing that on anything other than the position of his name in the citation I'd love to see it.

As per what I know of the Oste study (mainly what is reported by Beyondveg), it is perfectly plausible, absent evidence to the contrary, that enzymes and some nutrients are destroyed at 40 degrees Celsius but that no significant changes to the digestability of the protein take place until temperatures of close to 100 Celsius are reached.  Just because charred, well done meat is significantly less digestible than raw does not require that meat cooked rare be at all less digestible than raw (yes, some nutrients are destroyed, but that is entirely a separate question.)

As per the creation of AGE's and other toxins, in all things it is the dose that creates the poison.  While these substances are arguably detrimental in large quantities and probably never beneficial it is still an assumption to believe that in small quantities the body is incapable of dealing with them without lasting harm.  Dr. Eades has pointed out that no evidence exists that the consumption of AGE's in ones diet causes any increase of AGE's to be stored or formed in the body.  I don't know if he's right, but I haven't seen any evidence to contradict him.  This point on AGE's seems applicable to both vegetables and meat.  Your other point on phytonutrients versus antinutrients seems to me to be a question solely of quantity consumed without regards for preparation method.

[xylothrill]

In his book, Experiments and observations on the gastric juice, and the physiology of digestion
 Dr. William Beaumont experiments on the victim of a gunshot wound who has been left with on open stomach. I haven't re-read this but I do believe that, according to this, cooked meat does seem to digest faster than raw meat but neither digest as fast as plant matter, at least so far as the stomach is concerned. He also found that digestion outside the body was slower, if I remember correctly. This is only one person though.

[JustAnotherExplorer]

In his book, Experiments and observations on the gastric juice, and the physiology of digestion
 Dr. William Beaumont experiments on the victim of a gunshot wound who has been left with on open stomach. I haven't re-read this but I do believe that, according to this, cooked meat does seem to digest faster than raw meat but neither digest as fast as plant matter, at least so far as the stomach is concerned. He also found that digestion outside the body was slower, if I remember correctly. This is only one person though.

Google will only let me look at so much of the book, and I've reached my limit but it seems that you are correct.

[xylothrill]

He did have a compromised stomach. My own experience has been that cooked food and neolithic carbs drive my stomach acid up. This probably causes faster digestion but may be a defense mechanism to something the body sees as "foreign" being ingested. I have no way of telling how much faster or slower my digestion is now but I sure can attest to the fact that it's much better than it was on SAD.

[goodsamaritan]

In my personal timings, assuming I do not stuff myself with food and observe digestion of food eaten one kind at a time, this is my observation:

raw ripe fruit: 20 minutes
raw meat such as beef or tuna: 60 minutes

If I stuff myself with too much raw meat, it can take 4 hours.

Lesson for myself is not to stuff myself with too much food in one sitting.  It seems my digestive capacity only goes for so much food eaten at one sitting.

It is worse when I stuff myself with cooked meat, I get so so so sleepy.

[TylerDurden]

Wrangham's name is on the python paper but I have no clue how much work he actually did on the project.  It is very common in academia for supervisors who have done no or little work to have their names put on papers above their subordinates.  I do not know if that is what happened in this case or not.  How is it that you are aware that he was "intimately involved?"  If you're basing that on anything other than the position of his name in the citation I'd love to see it.

This is just quibbling. The fact is that Wrangham is the one who's been interviewed concerning this paper, not Conklin-Britton or any of the others, so he must have been intimately involved in the whole process - scientists who claim credit for work they haven't done tend to get blacklisted, so it's a career-killer for them to to do so. Granted, you may claim that Wrangham set the conditions/requirements of the test and some junior scientist did the actual experiment, but, even so, that means that Wrangham still had a major influence on the experiment, one way or another. So, really, it's up to you to prove that Wrangham had no control or influence over the various cooked-food studies he cites, despite his writing about it, being the main one interviewed about it etc.

As per what I know of the Oste study (mainly what is reported by Beyondveg), it is perfectly plausible, absent evidence to the contrary, that enzymes and some nutrients are destroyed at 40 degrees Celsius but that no significant changes to the digestability of the protein take place until temperatures of close to 100 Celsius are reached.  Just because charred, well done meat is significantly less digestible than raw does not require that meat cooked rare be at all less digestible than raw (yes, some nutrients are destroyed, but that is entirely a separate question.)

This is a mere technicality. Here's another study which proves my point:-

http://jn.nutrition.org/cgi/reprint/7/4/367.pdf

The above is a comparison between raw meat and 3 types of cooking at various temperatures, 1 of which involved cooking at 66-75 degrees Celsius for a period. All 3 cooking-methods showed a decrease in nutritive value and a clear drop in digestibility of meats after heating:-

"By the criterion of growth promoted among young rats(table 3), quite parallele differences are deduced. The raw meat is superior to all the cooked products, since each gram of raw meat protein eaten produced 0.78+/- 0.7 gm greater gain(i rats) than did that auto-claved 1 hour, 0.17 +/- 0.6 more than the boiled and 0.14 +/- 0.06 more than that autoclaved 7 minutes.

The other aspect is that since enzymes start getting destroyed at c.40 degrees Celsius, digetibility of meat is reduced. Yes, I know, that pro-cooked-advocates deny the uses of enzymes in raw food, but given the above facts re digestibility of protein being reduced at only slightly higher temperatures, it's clear that they are quite wrong.

As per the creation of AGE's and other toxins, in all things it is the dose that creates the poison.  While these substances are arguably detrimental in large quantities and probably never beneficial it is still an assumption to believe that in small quantities the body is incapable of dealing with them without lasting harm.  Dr. Eades has pointed out that no evidence exists that the consumption of AGE's in ones diet causes any increase of AGE's to be stored or formed in the body.  I don't know if he's right, but I haven't seen any evidence to contradict him.  This point on AGE's seems applicable to both vegetables and meat.  Your other point on phytonutrients versus antinutrients seems to me to be a question solely of quantity consumed without regards for preparation method.

As regards AGEs, Eades is merely expressing an opinion, based on no real data. All the studies show, unequivocally, that the more AGEs you ingest via cooked-food, the worse your health becomes(eg:-

http://www.circ.ahajournals.org/cgi/content/full/110/3/285

)

The very fact that it takes time for people to get diseased from the accumulation of AGEs implies, by definition, that the AGEs are stored in the  body until a critical point is reached. So, Eades is clearly wrong. Besides, there are plenty of studies focusing on the formation and accumulation of AGEs in tissue:-

http://www.jleukbio.org/cgi/content/full/71/3/433

http://www.springerlink.com/content/rwm8p2pyb4kj3q5w/

As regards the toxicity of AGEs, yes, of course,it's all a matter of degree - boiling is better than frying which is better than microwaving etc., but raw is far better than any cooking-method, on an overall level. I am not suggesting that AGEs are as toxic as cyanide but they are clearly a cause of physical degeneration of the human body as a result of eating cooked-foods. It is true, that extremely microscopic traces of AGEs can be found even in raw foods, which the human body can easily handle, but the amounts of AGEs in cooked-/processed foods is so much greater, by comparison, that the body is not equipped on an evolutionary level to deal with those much higher amounts. To argue that humans are adapted to the amounts of AGEs we consume(ever since the invention of cooking), you would have to prove, unequivocably, that we need to eat AGEs in order to live(that is, if you support Wrangham's and others' claim that cooked food is "better/healthier" for humans than any raw food) or(if you believe that there's no real difference between raw and cooked food) you have to prove that the human body can tolerate the amounts of AGEs present in cooked-foods - something which has been disproven by numerous scientific studies, detailing the links between AGEs and diabetes/macular degeneration etc. etc.:-

http://www.rawpaleoforum.com/important-info-for-newbies/info-on-toxins-in-cooked-foods/



Re phytonutrients:- Heating reduces phytonutrient levels. But, yes, it's a matter of how many there are:- too many, and they cause harm, too few and there's no benefit(unless one believes the zero-carbers, that is).

[JustAnotherExplorer]

T. Colin Campbell, whose name appears second on Diet, Life-style and Mortality in China: A Study of the Characteristics of 65 Chinese Counties is certainly the most well known figure associated with this study.  He is the one who's been interviewed concerning it and has been promoting it.  I think that we can agree that in doing so he has greatly distorted the findings of that large and comprehensive epidemiolgical paper.  I think that it is fair to criticize Campbell and his interpretations of the study, particularly that work of propaganda/fiction that he published as "The China Study" but I have come across no one who has impugned the data from or execution of the original study (other than the normal limitations of epidemiological research, of course, and that some of the questions were poorly worded).  The fact that he has been misusing and perverting the data to his own end does not mean that the original data is flawed.

I think that this is analogous to Wrangham.  We can accept the data of the python study without having to accept any of Wrangham's far-fetched conclusions.  It would be a career-killer for Stephen Secor, who has studied and published more about the digestion of pythons than anyone else, to publish research that could be so easily falsifiable by anyone else who is willing to do the experiment.  I do not claim that Wrangham set the conditions and that some junior scientist did the work.  As reported by Science and Health journalist Rachael Gorman, http://www.rachaelgorman.com/article_full.php?article_stamp=1202161241, Wrangham sought out Secor because he already had experience studying the evolutionary design of the digestive system.  Yes, the research found what Wrangham wanted it to find and he uses it to prop up his theories, but I don't think that that indicates the data to be erroneous any more than I think that the data actually supports his theory.  As I've said before, I find it very hard to believe that the snake data in isolation tells us anything meaningful about the human digestive tract.  I also don't think that this study tells us anything about the quality of the nutrition that the snake is absorbing.  It just tells us that the snake can absorb cooked food more quickly and with less energy than it can raw food.

This is a mere technicality. Here's another study which proves my point:-

http://jn.nutrition.org/cgi/reprint/7/4/367.pdf

The above is a comparison between raw meat and 3 types of cooking at various temperatures, 1 of which involved cooking at 66-75 degrees Celsius for a period. All 3 cooking-methods showed a decrease in nutritive value and a clear drop in digestibility of meats after heating:-

"By the criterion of growth promoted among young rats(table 3), quite parallele differences are deduced. The raw meat is superior to all the cooked products, since each gram of raw meat protein eaten produced 0.78+/- 0.7 gm greater gain(i rats) than did that auto-claved 1 hour, 0.17 +/- 0.6 more than the boiled and 0.14 +/- 0.06 more than that autoclaved 7 minutes.

I do not think that this study proves your point any more than the Oste one does.  The Morgan Kern study is a comparison of raw meat along with 3 samples cooked in different ways.  One sample was boiled until an internal temperature of 84C was reached.  The second was autoclaved at 15 pounds of pressure for 7 minutes, giving a temperature of 84C.  The last was autoclaved at 15lbs of pressure for 1 hour.  The authors did not measure the temperature of this sample, but admit that it probably exceeded 85C.  84C is equivilent to 183F and is far beyond well done.  At no time did the authors of this study examine lightly cooked meat.

The reference to a sample cooked from 66-77C is not from this study but is mentioned as the author discusses all previous studies done in this area of research.  This number came from the work of Jarawussa in '29.  Jarawussa's study found absolutely zero difference in biological value when comparing the raw substance with the cooked.  I say substance instead of meat because Jarawussa used a mixture of "100 gm. of meat, treated in one of the ways given above, with 40gm. of potatoes, 20 gm. of cabbage and 10 gm. of carrots."  Even if the Jarawussa study had only looked at meat and had come to a conclusion that the raw meat showed a difference in biological value it still wouldn't tell us anything about cooking meats to Rare (46-51C).  66C (151F) is considered medium rare by the USDA, but any chef in a kitchen will tell you that their numbers are wacky and that 66C is more Medium to Medium-Well.

The other aspect is that since enzymes start getting destroyed at c.40 degrees Celsius, digetibility of meat is reduced. Yes, I know, that pro-cooked-advocates deny the uses of enzymes in raw food, but given the above facts re digestibility of protein being reduced at only slightly higher temperatures, it's clear that they are quite wrong.

If by "the above facts re protein digestibility being reduced" you are referring to the Oste, Morgan and Jarawussa studies and not something else that I've overlooked then I hope that I have demonstrated that they do not tell us anything about what happens between, say, 40C and 60C.  The question about whether enzyme rich foods actually benefit us or if the enzymes are all broken down into basic amino acids in the stomach seems to be still up in the air.  It is still possible that the enzymes are deactivated at 40C but that there is no change in protein digestibility until 58C, to pick a random number.

The issue of the AGE's is more complicated and one where I will have to spend much more time reading through the references that you have provided before I feel that I'll be able to comment intelligently.

On phytonutrients and plants it seems that if too many cause harm and too few give no benefit then cooking which, depending on the method chosen and how it is executed, reduces but generally does not eliminate these compounds and which, according to Oste, makes the plants more digestible might be the preferred way to prepare and consume them.

[Satya]

T. Colin Campbell, whose name appears second on Diet, Life-style and Mortality in China: A Study of the Characteristics of 65 Chinese Counties is certainly the most well known figure associated with this study.  He is the one who's been interviewed concerning it and has been promoting it.  I think that we can agree that in doing so he has greatly distorted the findings of that large and comprehensive epidemiolgical paper.  I think that it is fair to criticize Campbell and his interpretations of the study, particularly that work of propaganda/fiction that he published as "The China Study" but I have come across no one who has impugned the data from or execution of the original study (other than the normal limitations of epidemiological research, of course, and that some of the questions were poorly worded).  The fact that he has been misusing and perverting the data to his own end does not mean that the original data is flawed.

This might interest you, as it exposes flaws in The China Study conclusions:

http://www.cholesterol-and-health.com/China-Study.html