Bioavailability of protein from raw meat?

[Diana]

Does anyone know the bioavailability of protein from raw meats? I have not been able to find this info. Thanks!

[RawZi]

    I've heard that cooked meat only has a quarter of the bio-availability of protein that raw does.  I know I get no good use out of cooked meat protein.  It left me skinny a hell and in pain.  I know raw grows my muscles.  Thanks for asking this question.  I would like to see the studies too.

[rawlion]

Cooking also makes meat more digestible. Proteins are like origami - complex, folded, three-dimensional structures that stomach acids and enzymes can't easily access. Heat unfolds the proteins, exposing them to enzymes that chop up the amino acids so they can be recycled into proteins the body needs.

To explore how much cooking ramps up the caloric potential of food, Wrangham teamed up with Stephen Secor, an expert in the physiology of digestion at the University of Alabama, Tuscaloosa. Secor tested the impact of cooking and grinding food on the ability of Burmese pythons to digest and absorb the nutrients. Pythons may sound like a strange choice, but they are useful models for studying digestion because they remain motionless for days after eating, making it easy to link changes in metabolism to the food they have eaten.

Secor fed the snakes one of four options: intact raw steak, intact cooked steak, ground raw steak or ground cooked steak. He found that cooking or grinding the meat reduced the cost of digestion by 12.7 per cent and 12.4 per cent respectively. When he fed the pythons steak that had been both ground and cooked, the combination lowered the amount of energy needed to digest the meal by 23.4 per cent.

"That's a significant decrease in the cost of digestion," says Secor. "It means that there are that many more calories that can be allocated to other activities, like glucose or fat storage."

SOURCE

[Hannibal]

Cooking also makes meat more digestible. Proteins are like origami - complex, folded, three-dimensional structures that stomach acids and enzymes can't easily access. Heat unfolds the proteins, exposing them to enzymes that chop up the amino acids so they can be recycled into proteins the body needs. 

That's a myth.
Raw animal proteins are quicker to digest than cooked ones. That's proven.

[rawlion]

After ingestion of the cooked egg protein meal, a substantial quantity of nitrogen was recovered in the ileal effluent over 24 h. The calculated yield of endogenous nitrogen (i.e., 0.40 g N) was close to the yield of 0.55 g N obtained by other researchers after ingestion of 17 g of pea protein (Gausserès et al. 1994). The calculated true ileal digestibility of cooked egg protein amounted to 91%. This finding demonstrates that even cooked egg protein, which has generally been considered to be easily digestible, is malabsorbed to some extent after ingestion of a physiologic load. Incomplete assimilation of dietary protein may have important consequences not only from a nutritional point of view, but also from a gastrointestinal point of view. Indeed, some metabolites resulting from bacterial fermentation of malabsorbed proteins in the colon have been implicated in the ethiopathogenesis of diseases such as colonic cancer and ulcerative colitis (Macfarlane and Cummings 1991, Pitcher and Cummings 1994, Visek 1978). It has already been reported extensively that food processing can influence protein digestibility both beneficially and detrimentally (Öste 1991). Egg white protein is generally considered to be less digestible than heat-pretreated egg white protein. However, no data are available concerning the magnitude of this impairment in vivo. In this study, it was shown that after ingestion of 25 g of raw egg protein, almost 50% is malabsorbed over 24 h. The higher digestibility of cooked egg protein presumably results from structural changes in the protein molecule induced by heating, thereby enabling the digestive enzymes to gain broader access to the peptide bonds. It has been suggested that the reduced digestibility of raw egg white is at least partially related to the presence of trypsin inhibitors in raw egg white (Matthews 1990). Ovomucoid is quantitatively the most important trypsin inhibitor (Gilbert 1971, Kassell 1970). Ovomucoid, however, does not react with human trypsin and, moreover, is relatively heat stable (Kasell 1970). Whether other egg trypsin inhibitors (e.g., ovoinhibitor or papain inhibitor) interfere with the digestibility of unprocessed egg white protein is unknown.

SOURCE

[carnivore]

Any rawfooders know that raw animal product are easier to digest than cooked animal products. All these studies are obviously made by non raw fooders.
Cooking only eases the digestion of food that can't be eaten raw, like beans, cereals, vegetables, simply because the majority of antinutrients and toxins are destroyed by the heat.

[rawlion]

Does not stomach acid denatures proteins and makes them more digestible? Does not fermentation of dairy and ageing of meats do the same thing?

[carnivore]

Does not stomach acid denatures proteins and makes them more digestible? Does not fermentation of dairy and ageing of meats do the same thing?

Yes it does. Contrary to heating that destroy nutrients and create many toxins.

[TylerDurden]

On an anecdotal level, Arnold Schwarzenegger revealed in his autobiography that when he was in the Austrian Army(and still doing bodybuilding competitions), he found that the meats in the Army canteens were significantly overcooked, so that in order to get enough (utilisable) protein, he had to eat twice as much as normal in order to get sizeable muscles, and then, of course, he had to exercise twice as much in order to get rid of the excess flab.


Re Wrangham:- This guy is  a fraud, so any studies by the guy can reasonably be treated with contempt. He made a ridiculous claim once that someone on a raw animal and raw vegetable diet would have to spend 5.7 to 6.2(!) hours chewing foods every single day in order to get enough calories from such a raw diet in order to thrive. This not only shows that he has never met a RVAFer let alone studied them, but the greatly exaggerated figure is so unrealistic, he must have just arbitrarily made it up. And that's not even taking into account the fact that evidence of cooking c.1.8/1.9 million years ago is heavily disputed and too sparse to be remotely credible.

Re studies done on lowered protein-digestibility of cooked animal foods. Here's a paragraph:-

"What is much more interesting is that BYV openly admits that cooking at 100 degrees C plus decreases the protein digestibility of fish and meat(meat being a primary food of the Palaeolithic diet which BYV advocates):- “From Oste [1991], heating (above 100°C, or 212°F) decreases meat protein digestibility. Frying chickpeas, oven-heating winged beans, or roasting cereals at 200-280°C (392-536°F) reduces protein digestibility. Seidler [1987] studied the effects of heating on the digestibility of the protein in hake, a type of fish. Fish meat heated for 10 minutes at 130°C (266°F), showed a 1.5% decrease in protein digestibility. Similar heating of hake meat in the presence of potato starch, soy oil, and salt caused a 6% decrease in amino acid content.” (Taken from Part 2a of the article linked immediately above)"

taken from:-

http://www.rawpaleodiet.com/anti-raw-bias-on-beyondvegcom-website-debunked/

I found it amusing that the above link was 1st on google, with the beyondveg.com ranking only 2nd(all I did was search for "beyondveg.com oste").

Re eggs:- The eggs studies are flawed because they focus on raw, unfertilised eggs. In the wild, eggs would have been laid only seasonally by birds in relativley inaccessible places, not all year round, implying that they were only a rare treat in palaeo times given lack of domestication of birds( apparently, constant egg-laying requires massive amounts of unhealthy grains); plus they would mostly have been fertilised, so that the antinutrient avidin would have been greatly reduced via fertilisation and the digestibility of such raw fertilised eggs would have been increased. Plus, digestion would be less harmful since no heat-created toxins such as AGEs would have been present in the raw eggs.Oh, and the denaturing of proteins created by cooking, not the same as the denaturing done via stomach-acids, forces the body to work harder re digestion, requiring more digestive enzymes, thus harming the body over time through strain.It's no surprise that many cooked-foodists as they get older develop digestive problems and require enzyme supplements in order to enhance digestion.

[rawlion]

Obviously meats should not be overcooked or cooked using high heat because more moisture is lost and the protein molecules bind closer together thus making it more difficult to digest and assimilate. But I wonder if cooking "the paleo way" may increase the nutritional value of meats and proteins in particular? For some reason no culture on Earth eats all raw diet...

[Hannibal]

Re eggs - the raw white is the culprit - it has got enzyme inhibitors, antinutrients; it is only useful to maintain freshness of the yolk
When I eat eggs I only eat yolks, which digest very fast.

[TylerDurden]

Obviously meats should not be overcooked or cooked using high heat because more moisture is lost and the protein molecules bind closer together thus making it more difficult to digest and assimilate. But I wonder if cooking "the paleo way" may increase the nutritional value of meats and proteins in particular? For some reason no culture on Earth eats all raw diet...

Cooking in palaeo times could be rather harsh, re forms of grilling over fires(they didn't have containers for most of the Palaeolithic era, so presumably couldn't boil their foods). As for denaturing of proteins via cooking, the effects do not magically appear at high-temperatures, the process is gradual, with boiling affecting foods very slightly and negative effects gradually increasing as higher temperatures are reached.

As for that foolish claim re no culture on Earth eating an all-raw diet, that is a meaningless comment since it falsely assumes that what humans do is by definition logical and correct. Many humans do stupid things en-masse such as smoking etc, for example.

To give another example, it's often falsely assumed that hunter-gatherers have always lived in perfect sync with their environment, not overly harming it, in accordance with the ridiculous "Noble Savage" theory. Yet, we have plenty of examples of modern hunter-gatherer types insisting on hunting what are now endangered species(such as the Masai insisting on killing lions related to puberty-rites, Inuit insisting on killing whales etc.). And then there was Palaeoman who wiped out huge numbers of species, especially larger game, by the end of the Palaeolithic era, thus forcing them to adopt an unhealthy agrarian, Neolithic diet in order to survive. So, adopting a practice, even if it's 100% practised by everybody, doesn't make it a logical one. In the case of cooking, it looks as though cooking was used to render some tubers/vegetables edible for human consumption; then once the addictive nature of cooking was discovered re addictive opioids in cooked foods, cooking was introduced for other foods as well.

[Hannibal]

For some reason no culture on Earth eats all raw diet...

For some reason no cultures are optimally healthy, don't live up to 150 years, etc.
People are rather opportunistic. Do you know why Europeans ate less and less of the organ-meats during the latest 200 years? Because they have become squeamish, not because the organ-meats were unhealthy.
Excerpt of the book "In The Devil's Garden" of Stewart Lee Allen:

"It was at some point during the late 1700s that the sacred meats of Tuscany began their long journey into disgrace. The most logical explanation for this demonition was Europe's increasing urbanization and the propensity of organ meats to spoil. Where in the past the European elite had enjoyed them deep in the forest after a kill, they now became the dish of people who lived near the cities' enormous slaughterhouses in hoods called "shambles", mazelike arrondisements puddled with coagulating blood and the stench of death. Hearts, kidneys, liver, udders, spleens, and blood pudding became Europe's soul food, both loved and hated"

[majormark]

Secor fed the snakes one of four options: intact raw steak, intact cooked steak, ground raw steak or ground cooked steak. He found that cooking or grinding the meat reduced the cost of digestion by 12.7 per cent and 12.4 per cent respectively. When he fed the pythons steak that had been both ground and cooked, the combination lowered the amount of energy needed to digest the meal by 23.4 per cent.
SOURCE

Only 23.4% ? That's nothing compared to the energy it would probably take for the body to deal with the heat created toxins...

I don't know about you but when I eat cooked meat it seems to slow me down compared to raw which actually seems to give me more energy.

This is probably the same thing like the avidin studies vs people who eat 30-40 raw eggs a day. I think they show a narrow and distorted view and not how things actually are.

[carnivore]

Obviously meats should not be overcooked or cooked using high heat because more moisture is lost and the protein molecules bind closer together thus making it more difficult to digest and assimilate. But I wonder if cooking "the paleo way" may increase the nutritional value of meats and proteins in particular? For some reason no culture on Earth eats all raw diet...

Less toxins is better than more toxins, but zero heat created toxins is even better!
Less nutrient loss is better than more nutrient loss, but zero nutrient loss is even better !

Whatever is the "paleo way" of cooking, it is a recent artifice in human history that brings no advantage regarding the consumption of animal products. Cooking is just an artifice to eat non paleo food (grain, beans, ...).

[Nation]

If we compare 2 identical pieces of meat, 1 medium cooked and 1 is raw. We get a higher % of calories from fat from the raw meat, right?  And more calories overall too?

[TylerDurden]

If we compare 2 identical pieces of meat, 1 medium cooked and 1 is raw. We get a higher % of calories from fat from the raw meat, right?  And more calories overall too?

  Strictly speaking, cooking reduces the amounts of calories, only slightly if the meat is minimally-cooked, and a great deal if the meat is overcooked.

[alphagruis]

If we compare 2 identical pieces of meat, 1 medium cooked and 1 is raw. We get a higher % of calories from fat from the raw meat, right?  And more calories overall too?

It depends on how one counts the calories.

In a given piece of food the total number of physically available calories (by burning in a calorimeter) is reduced in all instances when compared before and after cooking. For a very simple reason which is that cooking begins the process of using the initially available calories for instance by oxidation, glycation, and all overall necessarily exothermic spontaneous chemical reactions that take place.

The total number of bioavailable calories is a different thing which depends on digestive capabilities. In meat and fat the bioavailable calories are a priori even more reduced than the physically available ones because of digestion impairing by damaged molecules.

In starchy foods the ansver is however much less obvious and the number of bioavailable calories might well increase because of starch splitting into simple sugars by heat. This possibility seems supported by some food science work.

Finally if one considers what's actually most important in practice namely the bioavailable calories per ingested gram or ounce of food before and after cooking this also most likely increases rather than decreases in general (even for meat ) because of the main effect of cooking which is a big loss of water. At least if the food is not overcooked.   



 

[cherimoya_kid]

For some reason no culture on Earth eats all raw diet...

Humans can live to 120 or longer if they eat an ideal diet and have an ideal lifestyle.  None of the cooked-food cultures live to 120 on average.

[Hannibal]

None of the cooked-food cultures live to 120 on average. 

Ethiopians in ancient times lived about 120 years - Herodotus wrote about this. They ate boiled meats and milk products, without any grains, etc.

[Nation]

On the topic of raw vs cooked meat. When i did cooked ZC for 3-4 months, my average weight was ~65 kgs despite eating pretty large quantity of meat. I'd eat about 1kg of meat a day, (1 kg raw that i cooked). I weighed myself yesterday after being raw for a lil more than a month and i gained 3 kilos despite eating much less meat, i'd say i eat 30% less quantity of meat (about 0,7 kg a day. I'm pretty happy with my current weight of 68 kgs, i'm 5"9.

[cherimoya_kid]

Ethiopians in ancient times lived about 120 years - Herodotus wrote about this. They ate boiled meats and milk products, without any grains, etc.

Herodotus this, Herodotus that.  Even if it's true, they may have had other things they did, that we don't know about...certain herbs, certain health practices, etc.

[Hannibal]

Herodotus this, Herodotus that.  Even if it's true, they may have had other things they did, that we don't know about...certain herbs, certain health practices, etc.

Persian people, contemporary to Ethiopians, lived up to 80 years and they ate mainly grain products.

[goodsamaritan]

On the topic of raw vs cooked meat. When i did cooked ZC for 3-4 months, my average weight was ~65 kgs despite eating pretty large quantity of meat. I'd eat about 1kg of meat a day, (1 kg raw that i cooked). I weighed myself yesterday after being raw for a lil more than a month and i gained 3 kilos despite eating much less meat, i'd say i eat 30% less quantity of meat (about 0,7 kg a day. I'm pretty happy with my current weight of 68 kgs, i'm 5"9.

I have the impression that carbs are protein sparers and that the proteins are used to build muscle instead of used up as fuel?

Plus carbs allow us to get fat?

[William]

I have the impression that carbs are protein sparers and that the proteins are used to build muscle instead of used up as fuel?

Plus carbs allow us to get fat?

From experience, carbs are fat sparers, in that if we can't get enough animal fat, we can fuel our bodies with carbs.
The bad side effects from doing this are well known, such as obesity.

The components of proteins and animal fats are used to build and rebuild everything.