Medical How does a dietary intake of 100% animal fat mimic fasting?

[Vintageliving]

I have read some things such as reports of the Stefansson Bellevue experiment, or his reports of the Eskimos, and a few references to the research of Pennington, Kekwick, Donaldson, MacKarness, and their having patients on a dietary intake of low carbohydrate or very low carbohydrate, moderate protein and high fat. These dietary regimes are for ongoing nutrition, or care for those who have allergies or need to lose weight.

With more research being done about ketogenic diets for those with cancer, epilepsy, Alzheimer's, and other serious illness, this brings new avenues of possibility. There are many on low-carb and Paleo forums who post reports of doing very well on ketogenic diets, in many variations.

I am interested to know if the rest and regeneration which fasting gives would be duplicated, for lack of a better word, by a diet of 100% fat, say 100% pastured beef suet, for something which has nutrients and a good Omega 3 to 6 ratio. Hydration with clean water, free of contaminants and additives.

Would the diet of animal fat supply the body with nutrients so that the unwanted aspects of fasting are avoided, while giving the body the specific benefits that fasting does?

I apologize, I do not know enough to ask more specific questions.

If there are those among you who are interested in such things, and wouldn't mind explaining this to a "lay person", I would appreciate whatever you'd be willing to post.


Thank you very much.

 

[bobze]

Your body needs carbohydrates, period. Despite what any "new age" diet "gurus" claim. Your brain and red blood cells can only use glucose (and ketone bodies under starved states, more on this in a minute).

Other cell types in your body prefer to use different nutrients for http://en.wikipedia.org/wiki/Glycolysis" , such as your intestinal epithelium which prefers to use glutamate for its carbon source.

If you eat a diet free of "carbs" your liver only sees the hormone glucagon (think "glucose is gone"). This sets off a cascade of events (namely through protein kinases) which turns off glycolysis in your liver and starts running http://en.wikipedia.org/wiki/Gluconeogenesis" . Why does your liver do this? Because as I pointed out above, your brain and RBCs need glucose.

Not all sources of carbon can be used to make glucose to feed your brain and RBCs. Most fats cannot be used to make glucose (the exception is odd carbon number chain fatty acids which produce a propionyl-CoA as the last step of beta-oxidation). Almost all amino acids are glucogenic (ie; they can be used to make glucose). Which in the case of a low carb diet isn't necessarily a good thing (if you're not eating enough protein) because that means your body will begin break down muscle (protein) to feed the brain and RBCs.

Your body has an inbuilt safety for this, under conditions of starvation your body assumes you require muscle (to hunt and gather more food) so your liver's main source for ATP during starvation comes from the oxidation of fatty acids (released from your fat stores, or from a "diet of 100% fat). The excess of acetyl-CoA under these conditions leads your body to produce ketone bodies, which the brain and RBCs can use for about 30-40% of their energy demands. This means (from your body's standpoint, less muscle degradation and longer buffer period where you can find food).

The problem with prolonging these conditions (asides from becoming http://en.wikipedia.org/wiki/Hypoglycemia" , which affects your body in many negative ways (it turns out your body likes to maintain a certain homeostasis and doesn't take kindly to things like changing pH).

Omega 3 and Omega 6 fatty acids are just advertising gimmicks. What sounds safer to eat; omega 6 fatty acids or cis-9,12 linoleic acid? Probably the former, but they are one in the same.

Omega fatty acids are just unsaturated fats that your body can't synthesize (you cannot make the 9-12 or 9-12-15 split double bonds in the carbon back bones). So these are essential fatty acids (like you have essential amino acids) you need as precursors for more complex fats, which you mostly use for cell-cell signaling (like http://en.wikipedia.org/wiki/Prostaglandin" ).

If you want to feel good and have a healthy diet don't spend money on new age guru books, learn about evolution (you know the unifying theory of biology; "nothing in biology makes sense except in light of evolution"--Including our diets). We evolved over the last few million years eating seasonal varied diets of complex plant carbohydrates, simple animal carbohydrates, lean meats and healthy animal fats. Spending your time emulating that, making sure you meet your essential nutrient (including vitamins) demands and staying physically active should lead to desirable outcomes, any genetic problems aside (and you save the 14.95 you would have spent on a book called "stuff my pockets and follow my ridiculous diet" to boot).

 

[Vintageliving]

Bobze, thank you for taking the time to post.

My question is one of scientific interest.

I like to find out about things, and be able to answer specific questions, and ask questions of others, when subjects arise.

I asked the question on this forum, because I would like to know to know the chemistry involved.

 

[bobze]

Bobze, thank you for taking the time to post.

My question is one of scientific interest.

I like to find out about things, and be able to answer specific questions, and ask questions of others, when subjects arise.

I asked the question on this forum, because I would like to know to know the chemistry involved.

Not to discourage you but that is a lot of chemistry! The amount that would be best learned in some college courses.

 

[Siv]

Well there are lots of myths and misconceptions about carb and fat in the media and establishment.

Lets start with the common one that the body, esin needs carbs.

The body does not need dietary carbs, but will use them if supplied. If we don't eat enough glucose to fuel the brain, the liver can synthesis ketone molecules. Our bodies can manufacture all our glucose needs via gluconeogenesis, the process of converting protein into glucose. Also, some tissues which prefer carbohydrate metabolism to ketone metabolism, like our brain, will eventually convert to at least partial ketone metabolism.

And ketosis is very different from ketoacidosis, a commonly made mistake people use to portray low carb as a <shudder> <shudder? horrible thing.

Dietary ketosis is among the most maligned and misunderstood concepts in nutrition because it is often confused with ketoacidosis, which is a life-threatening condition most often associated with uncontrolled insulin-deficient Type 1 diabetes. In the Type 1 diabetic, the absence of insulin leads to a toxic build-up of blood glucose and an extreme break-down of fat and muscle tissue. This condition doesn't occur in individuals who have even a small amount of insulin, whether from natural production or artificially administered.

Dietary ketosis, however, is a natural adjustment to the body's reduced intake of carbohydrates as the body shifts its primary source of energy from carbohydrates to stored fat. The presence of insulin keeps ketone production in check so that a mild, beneficial ketosis is achieved. Blood glucose levels are stabilized within a normal range and there is no break-down of healthy muscle tissue.

The most sensitive tests of ketosis ("NMR" and "blood ketone level") show that everyone is in some degree of ketosis every day, particularly after not eating overnight and after exercising. Ketosis is the body's survival system. It is not an abnormality nor does it present any medical danger, except to a Type I insulin-dependent diabetic. The body functions naturally and effectively while in a state of dietary ketosis.

The danger of excess carbs, especially refined carbohydrates, is well known. Its no longer controversial or unproven. On the other threads, I have posted lots of evidence of the harm of carbs as well as the lack of evidence that saturated fats are bad.

 

[bobze]

Well there are lots of myths and misconceptions about carb and fat in the media and establishment.

That's true!

Lets start with the common one that the body, esin needs carbs.

The body does not need dietary carbs, but will use them if supplied. If we don't eat enough glucose to fuel the brain, the liver can synthesis ketone molecules. Our bodies can manufacture all our glucose needs via gluconeogenesis, the process of converting protein into glucose. Also, some tissues which prefer carbohydrate metabolism to ketone metabolism, like our brain, will eventually convert to at least partial ketone metabolism.

Your body does need carbs. Your brain can only use those "ketone molecules" (I suppose you mean ketone bodies here) for about 40% of its energy demands. The rest must come through gluconeogenesis. Not all compounds are glucogeneic. Most amino acids are, but living of amino acids for the glucose needs stresses the body in other unhealthy ways. Namely, amino acid (protein) metabolism leads to increased BUN levels, which negatively affect both your kidneys and your liver.

*Slight fyi gluconeogenesis is not the process of converting protein into glucose. It is the process of making glucose from any available carbon source. Glycerol, lactate, propinyl-CoA etc.

And ketosis is very different from ketoacidosis, a commonly made mistake people use to portray low carb as a <shudder> <shudder? horrible thing.

Dietary ketosis is among the most maligned and misunderstood concepts in nutrition because it is often confused with ketoacidosis, which is a life-threatening condition most often associated with uncontrolled insulin-deficient Type 1 diabetes. In the Type 1 diabetic, the absence of insulin leads to a toxic build-up of blood glucose and an extreme break-down of fat and muscle tissue. This condition doesn't occur in individuals who have even a small amount of insulin, whether from natural production or artificially administered.

Ketosis is when those "ketone molecules" is elevated. Its isn't a "good" or "bad" thing, but most often is a first indicator of a disease state. Ketoacidosis is when those "ketone molecules" get to dangerously high levels and begin to alter the blood pH. A diet of only animal fat is a sure way to end up here. Why?

Because the regulation of ketone bodies is not as regulated as other metabolic cycles. The production of "ketone molecules", is for better or worse, controlled by the amount of available acetyl-CoA available in the mitochondrial matrix. An abundance of AcCoA will lead to KB formation, whether it is poisoning your body or not.

AcCoA is the outcome of beta-oxidation of fats. So when your body is running B-oxidation, it naturally has an excess of AcCoA (important note here, CARBONS FROM AcCoA CANNOT BE USED FOR GLUCONEOGENESIS, the consequence of which means some substances, like lysine for instance, are ONLY ketogenic). In an evolutionary sense this makes "senses".

If the body is starving then you are burning only fat stores for energy. This also means blood glucose levels will be low (hypoglycemic) and the brain and RBCs energy demands maybe in peril. Making ketone bodies in this situation then would be beneficial.

The problem comes in disease states (extended starvation, anorexia, alcoholism, diabetes, or people who buy in too goofy diets) when KBs reach dangerous concentrations.

Dietary ketosis, however, is a natural adjustment to the body's reduced intake of carbohydrates as the body shifts its primary source of energy from carbohydrates to stored fat. The presence of insulin keeps ketone production in check so that a mild, beneficial ketosis is achieved. Blood glucose levels are stabilized within a normal range and there is no break-down of healthy muscle tissue.

Incorrect. As I pointed out the only thing that regulates how much KBs are being produced is AcCoA. Insulin, allows the uptake of glucose by cells with insulin-dependent GLUT receptors (such as muscle).

Edit to add: I suppose you could make the argument that insulin indirectly contributes to KB production (rather the lack of insulin), because of the increase in glucagon/insulin ratio, which further activates HSL, thus raising even more blood FFA levels.

Your blood glucose levels need to be maintained at about 90 mg%. Insulin only helps lower higher BGLs to this point. It does so by allowing cells such as muscle to take up glucose and by starting insulin-dependent cascades which result in the promotion of glycogen formation.

Glucoagon is responsible for bringing your BGLs up to this level when they are too low. Muscle DOES NOT HAVE GLUCAGON receptors, so with a increased glucagon/insulin ratio the muscle will not uptake blood glucose stores. While other organs, like the liver will respond through glucagon dependent cascades (namely through PkA) to start gluconeogenesis.

Your muscle glycogen stores run out very quickly (measured in the hours) and those metabolic end products (lactate) will be sent to the liver for gluconeogenesis. If you continue to not eat carbohydrates, the muscle will begin metabolize protein so that glucogenic amino acids can also be sent to the liver to raise and maintain blood glucose levels.

At about this point, the continued exposure of glucagon will activate hormone sensitive lipase, which causes fatty acid metabolism to start. The elevated blood level rise of fatty acids induce carnitine transport in the liver, where b-oxidation will result in increased AcCoA and as discussed above, will increase KB formation. The point of the KBs is to protect against muscle protein catabolism. And ketosis.

Continuing to not eat (or eat incorrectly) will result in even more fatty acid metabolism and even greater increases in KB formation and after extended periods of this ketoacidosis.

The most sensitive tests of ketosis ("NMR" and "blood ketone level") show that everyone is in some degree of ketosis every day, particularly after not eating overnight and after exercising. Ketosis is the body's survival system. It is not an abnormality nor does it present any medical danger, except to a Type I insulin-dependent diabetic. The body functions naturally and effectively while in a state of dietary ketosis.

The danger of excess carbs, especially refined carbohydrates, is well known. Its no longer controversial or unproven. On the other threads, I have posted lots of evidence of the harm of carbs as well as the lack of evidence that saturated fats are bad.

As I pointed out, ketosis is just the rise in KBs which happens naturally as your glycogen stores are depleted. It isn't a "good or bad" type of deal, it is a "just is" type of deal. However as I also pointed out, continued poor nutrition or disease states leads to elevations of ketosis to ketoacidosis.

Reading a "popularize of science book" (by a physicist too no doubt) isn't an alternative to medical education nor seeking real medical advice.

 

[Yanick]

I am interested to know if the rest and regeneration which fasting gives would be duplicated, for lack of a better word, by a diet of 100% fat, say 100% pastured beef suet, for something which has nutrients and a good Omega 3 to 6 ratio. Hydration with clean water, free of contaminants and additives.

How exactly does a fast provide rest and regeneration to an organism? This statement, to me, implies a deep misunderstanding of fundamental physiology. Can you clarify that statement please? It smells of popular diet book jargon.

As for the second part of your question. Fat and water are not the only things your body requires. Amongst the more important molecules your body requires are electrolytes, micronutrients and proteins. Electrolytes imbalances can cause illness/death in hours to days whereas micronutrient and protein deficiency typically takes much longer (months) and aren't typically lethal but can cause serious illness and/or lower quality of life (at best).

Would the diet of animal fat supply the body with nutrients so that the unwanted aspects of fasting are avoided, while giving the body the specific benefits that fasting does?

What unwanted aspects are you speaking of and what benefits do you feel fasting affords?

I apologize, I do not know enough to ask more specific questions.

If there are those among you who are interested in such things, and wouldn't mind explaining this to a "lay person", I would appreciate whatever you'd be willing to post.

I've been into Health and Nutrition since I was an overweight teenager trying to lose fat so I could score with chicks. In fact it was that motivation which exposed me to a good amount of physiology and biochemistry (and science in general) and which ultimately sparked an interest in science which has yet to be quenched, though I've strayed far from the health and nutrition arena of my youth. That was a decently long time ago. Let's just say I've been around the block when it comes to all sorts of diets.

I've done everything from Straight/Cyclic/Targeted Ketogenic Diets, to Protein Sparing Modified Fasts, to Intermittent Fasting to Carb Cycling to just straight calorie deficits with balanced macronutrient profiles etc, High Carb/Low fat, High fat/Low Carb and many in between. Come to think of it, the only macronutrient I've never cut out was Protein which makes sense because I came from a bodybuilding backround.

There is so much crap out there that if a person is not well versed in fundamental science then its almost impossible to tell the pseudoscience from the real science (euscience?). I'll just share a tidbit with you that most 'health/diet gurus' never will. Every single one of the diets that you ever read about will work. Fad diets trick you into eating less while telling you that you can eat as much as you want. Losing weight is a simple matter of calories in versus calories out. You create a caloric deficit via a)eating less or b)moving more and you will lose weight. The same can be said of any fad diet that is not necessarily promoting weight loss, but just good health. The easy part is following the '4 Phase Plan' as spelled out by the all knowing [insert guru here]. The tough part is actually maintaining a regimen which is both sustainable and healthy in the long run. The tough part is developing a balanced lifestyle which includes being 'mostly' healthy while maintaining your sanity at the same time. I say mostly because I've yet to meet a person, who is sane, who can really maintain one of those paleo-starvation-what-have-you diets 100% of the time for years on end. Everything in life is good for you, the key is knowing where/when/how to maintain the appropriate balance of the good-bad.

General rule of thumb, if someone is telling you that their method is the best method for everybody, across the board and at the same time is trying to explain how everything everyone else is doing is bad and wrong and that you need to buy their 3 phase diet plan or whatever, run and hide. They don't know what the hell they are talking about or they know exactly what they are talking about but they really want to make some cash. With overweight and obesity rates sky rocketing in most developed nations, everybody is looking for that quick, easy, black and white type of answer. The problem is that nothing in reality is ever black and white. Reality, IMO, is pretty much all shades of gray.

 

[bobze]

How exactly does a fast provide rest and regeneration to an organism? This statement, to me, implies a deep misunderstanding of fundamental physiology. Can you clarify that statement please? It smells of popular diet book jargon.

As for the second part of your question. Fat and water are not the only things your body requires. Amongst the more important molecules your body requires are electrolytes, micronutrients and proteins. Electrolytes imbalances can cause illness/death in hours to days whereas micronutrient and protein deficiency typically takes much longer (months) and aren't typically lethal but can cause serious illness and/or lower quality of life (at best).



What unwanted aspects are you speaking of and what benefits do you feel fasting affords?



I've been into Health and Nutrition since I was an overweight teenager trying to lose fat so I could score with chicks. In fact it was that motivation which exposed me to a good amount of physiology and biochemistry (and science in general) and which ultimately sparked an interest in science which has yet to be quenched, though I've strayed far from the health and nutrition arena of my youth. That was a decently long time ago. Let's just say I've been around the block when it comes to all sorts of diets.

I've done everything from Straight/Cyclic/Targeted Ketogenic Diets, to Protein Sparing Modified Fasts, to Intermittent Fasting to Carb Cycling to just straight calorie deficits with balanced macronutrient profiles etc, High Carb/Low fat, High fat/Low Carb and many in between. Come to think of it, the only macronutrient I've never cut out was Protein which makes sense because I came from a bodybuilding backround.

There is so much crap out there that if a person is not well versed in fundamental science then its almost impossible to tell the pseudoscience from the real science (euscience?). I'll just share a tidbit with you that most 'health/diet gurus' never will. Every single one of the diets that you ever read about will work. Fad diets trick you into eating less while telling you that you can eat as much as you want. Losing weight is a simple matter of calories in versus calories out. You create a caloric deficit via a)eating less or b)moving more and you will lose weight. The same can be said of any fad diet that is not necessarily promoting weight loss, but just good health. The easy part is following the '4 Phase Plan' as spelled out by the all knowing [insert guru here]. The tough part is actually maintaining a regimen which is both sustainable and healthy in the long run. The tough part is developing a balanced lifestyle which includes being 'mostly' healthy while maintaining your sanity at the same time. I say mostly because I've yet to meet a person, who is sane, who can really maintain one of those paleo-starvation-what-have-you diets 100% of the time for years on end. Everything in life is good for you, the key is knowing where/when/how to maintain the appropriate balance of the good-bad.

General rule of thumb, if someone is telling you that their method is the best method for everybody, across the board and at the same time is trying to explain how everything everyone else is doing is bad and wrong and that you need to buy their 3 phase diet plan or whatever, run and hide. They don't know what the hell they are talking about or they know exactly what they are talking about but they really want to make some cash. With overweight and obesity rates sky rocketing in most developed nations, everybody is looking for that quick, easy, black and white type of answer. The problem is that nothing in reality is ever black and white. Reality, IMO, is pretty much all shades of gray.

Good post

 

[Proton Soup]

bobze, i'd like to see some evidence that increased protein metabolism is bad for your kidneys. just because an increased BUN reading could indicate a kidney problem does not mean that increased excretion of urea is going to do damage.


in any case, if i were going to fast, i'd do a protein-sparing modified fast to control hunger and limit lean tissue losses. plus some fish oil for EPA/DHA and a multivitamin to limit nutritional deficiencies. it's no way to live, but then, neither is being obese.

http://www.ncbi.nlm.nih.gov/sites/entrez?db=pubmed&cmd=search&term=protein+sparing+modified+fast

 

[hamster143]

bobze, i'd like to see some evidence that increased protein metabolism is bad for your kidneys. just because an increased BUN reading could indicate a kidney problem does not mean that increased excretion of urea is going to do damage.

Clearing urea out of the blood is one of the primary functions of kidneys. High protein diets lead to higher quantities of urea being produced, leading to more load on kidneys, leading to their faster deterioration.

There's plenty of evidence that high-protein diets are bad for people with some kind of preexisting kidney damage, even if it's mild, e.g.

http://www.ncbi.nlm.nih.gov/pubmed/15073493

The effect on healthy kidneys is more controversial. Studies usually focus on short-term measurable effects such as the decrease in filtration rate, and that is not seen in people who switch to a high-protein diet. On the other hand, you're not going to find short-term measurable effects on the lungs in someone who starts smoking, either. And then at some point after 20 or 30 years the body reaches the limit and things start to break down.

Back to kidneys, at least one study back in 1990 found that people from the top quartile by protein intake had double the risk of renal cancer compared to people from the bottom quartile. 2x is not much and this cancer is quite rare to begin with. But, on the other hand, this was long before Atkins became a fad, and quantities of protein consumed by modern low-carb dieters are probably unheard of by the standards of 1990. Could be a good idea to get into the dialysis business by the time early adopters of Atkins start getting into their 60's.

 

[Siv]

Hello bobze,

Damn, that's a long post

I don't see you actually refute anything I said.
First you (thankfully) move away from saying our body definitely needs carbs to agreeing that 40% of these carb needs can be met by ketones. You further agree that the remaining can be met by gluconeogenesis, although you quibble over whether all compounds are glucogeneic. I can live with you disagreeing over that. As long as we've busted the myth that the brain can function only on carbs and all those carbs have to come from diet. And we've busted that big time, thanks

And re: the cliched claim that "amino acid (protein) metabolism leads to increased BUN levels, which negatively affect both your kidneys and your liver", Evidence please.

You also agree that there is a difference between ketosis and ketoacidosis. Thank you. Most people who shudder at the word ketosis are misplacing their shuddering by understanding ketosis as ketoacidosis.
But you seem too think that ketoacidosis is some progressively worse form of ketosis, which is not entirely correct.

BTW here is a study that shows how "dangerous" ketosis actually is
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2716748/

The data presented in the present study showed that a ketogenic diet acted as a natural therapy for weight reduction in obese patients. This is a unique study monitoring the effect of a ketogenic diet for 24 weeks. There was a significant decrease in the level of triglycerides, total cholesterol, LDL cholesterol and glucose, and a significant increase in the level of HDL cholesterol in the patients. The side effects of drugs commonly used for the reduction of body weight in such patients were not observed in patients who were on the ketogenic diet. Therefore, these results indicate that the administration of a ketogenic diet for a relatively long period of time is safe. Further studies elucidating the molecular mechanisms of a ketogenic diet are in progress in our laboratory. These studies will open new avenues into the potential therapeutic uses of a ketogenic diet and ketone bodies.

Ketones are a byproduct of fat metabolism, so if you follow any diet and lose weight (or lose weight due to other reasons), you will produce ketones.
Maybe all the metabolic processes that lead to ketone production in ketoacidosis are present in ketosis, yet ketosis will not lead to an acidotic condition.

Here's a lovely link that explains it well.

http://cxlxmxrx.blogspot.com/2009/02/ketosis-vs-ketoacidosis-part-2.html

I finally found the answer in section 8.2 of Kerry Brandis' Acid-Base Physiology, an outstanding (and open access!) publication I had run across before but forgotten about. It's quite simple. Insulin is an antagonist to free fatty-acid release by cells. Without insulin, higher rates of free fatty-acids are available to act as increased substrate for ketone production. The odd imbalanced ratio of acetoacetate-to-ß-hydroxybutyrate is caused by an imbalance in NAD+to-NADH ratio caused by lactic acidosis.

Of course, that's not the whole story. FFA production is also increased by stress hormones, which explains why DKA is often precipitated by an infection.

Diabetic Ketoacidosis (DKA) is seen primarily in patients with type 1 diabetes. The incidence is roughly about 3% of type 1 diabetic patients going into ketoacidosis when their pancreas first shuts down, and they are first diagnosed as diabetic. It can occur in type 2 diabetic patients as well if blood sugar is very uncontrolled. It is a serious condition that occurs in uncontrolled diabetics when their blood sugar is extremely high AND the bicarbonate is low (<15 mEq/L), AND they are in acidosis (pH <7.30). A low carb diet would be an excellent idea to stabilize blood sugars.

BTW not sure if you have read Dr. Bernstein. He has worked wonders in people with diabetes. With very low carb diets.

 

[Siv]

Clearing urea out of the blood is one of the primary functions of kidneys. High protein diets lead to higher quantities of urea being produced, leading to more load on kidneys, leading to their faster deterioration.

There's plenty of evidence that high-protein diets are bad for people with some kind of preexisting kidney damage, even if it's mild, e.g.

http://www.ncbi.nlm.nih.gov/pubmed/15073493

The effect on healthy kidneys is more controversial.

Yes, I know. All those who claim that high protien diets stress the kidneys run to these few studies, which are always about people with kidney problems

In fact fitness experts have been trying to bust this myth for decades. They regularly eat high protien diets.

http://www.ncbi.nlm.nih.gov/pubmed/10722779
Here's the abstract :

Do regular high protein diets have potential health risks on kidney function in athletes?
Poortmans JR, Dellalieux O.

Department of Physiological Chemistry, Institute of Physical Education and Kinesiotherapy, Free University of Brussels, Belgium.

Abstract
Excess protein and amino acid intake have been recognized as hazardous potential implications for kidney function, leading to progressive impairment of this organ. It has been suggested in the literature, without clear evidence, that high protein intake by athletes has no harmful consequences on renal function. This study investigated body-builders (BB) and other well-trained athletes (OA) with high and medium protein intake, respectively, in order to shed light on this issue. The athletes underwent a 7-day nutrition record analysis as well as blood sample and urine collection to determine the potential renal consequences of a high protein intake. The data revealed that despite higher plasma concentration of uric acid and calcium, Group BB had renal clearances of creatinine, urea, and albumin that were within the normal range. The nitrogen balance for both groups became positive when daily protein intake exceeded 1.26 g.kg but there were no correlations between protein intake and creatinine clearance, albumin excretion rate, and calcium excretion rate. To conclude, it appears that protein intake under 2. 8 g.kg does not impair renal function in well-trained athletes as indicated by the measures of renal function used in this study

The other myth is that high protien causes osteoporosis. Thats been debunked too.
http://jn.nutrition.org/cgi/content/full/128/6/1054

In fact our protien needs may have been underestimated. A 1994 study revealed the increased needs for the elderly.
http://www.ajcn.org/cgi/reprint/60/4/501.pdf

 

[hamster143]

In fact fitness experts have been trying to bust this myth for decades. They regularly eat high protien diets. ... The athletes underwent a 7-day nutrition record analysis as well as blood sample and urine collection to determine the potential renal consequences of a high protein intake.

:facepalm Like I said, a 7-day study of the effect of protein intake on filtration rates among middle-age bodybuilders is not going find any more harm than a study of the effect of smoking on VO2max among the same group. (Studies were done, the impact of smoking is minimal.) That does not mean there's no harm done.

What we really need is to look at the rates of chronic kidney disease and ESRD among the elderly (60+) and correlate them with (possibly self-reported) average lifetime protein consumption levels. We already know that a high-protein diet accelerates the progression from mild renal insufficiency to chronic kidney disease (link above) and from CKD to ESRD (http://ndt.oxfordjournals.org/content/15/12/1986.abstract). All we need is to connect the dots: even assuming that renal insufficiency is equally likely to occur among Atkins followers and carb eaters, the former group is far more likely to end up on dialysis. But I'm not aware of such study. And the myth of safety of high protein diets lives on.

 

[bobze]

bobze, i'd like to see some evidence that increased protein metabolism is bad for your kidneys. just because an increased BUN reading could indicate a kidney problem does not mean that increased excretion of urea is going to do damage.


in any case, if i were going to fast, i'd do a protein-sparing modified fast to control hunger and limit lean tissue losses. plus some fish oil for EPA/DHA and a multivitamin to limit nutritional deficiencies. it's no way to live, but then, neither is being obese.

http://www.ncbi.nlm.nih.gov/sites/entrez?db=pubmed&cmd=search&term=protein+sparing+modified+fast

Its not only BUN levels, but blood acidity in general. On most western diets we are slightly acidotic because of increased protein consumption. Your kidneys are built with an excess of nephrons, which in most cases mitigate this acidosis. But the general effect is to require your kidneys to work harder.

Increases in protein metabolism also lead to increases in ammonium excretion (through tubule lumen hydrogen ion loading), which is good because it reduces ammonia levels, but at the same time reduces concentration of final urine (not provisional, which remains isosmotic) and again requires more work on the kidney.

The problem with kidney disease (as apparent to anyone who's studied renal physiology) is the excessive GFR (glomular filtration rate), which glomular function doesn't take a "dive" until we've reached around 15% of our glomular function.

This is pretty basic medical renal physiology. For more information, I'd recommend https://www.amazon.com/dp/007161303X/?tag=pfamazon01-20.

*Just a note, I'm not saying "protein diets" are "bad", just as I was not saying that "carb diets" are "bad". We're far to individual for that. I will say, what I said a while ago, that if you really want a healthy diet you should seek to emulate that diet we evolved to eat. Namely, complex plant carbs in variety, lean meats and simple animal carbs and healthy animal fats. As Yanick pointed out though, the discipline required to adhere to such "stone-age" diets, is too much for most American's (and Westerners) in general, who live by the American motto of miracle cure-all's and get rich quick schemes.

The reality in our modern setting is that hard work and discipline are required to maintain health, there is no free lunch.

 

[bobze]

Hello bobze,

Damn, that's a long post

I don't see you actually refute anything I said.

You seem to under the impression that I was arguing with you, I wasn't. I was simply pointing out incorrect things you've said-Either because you've never actually studied human physiology, nutrition and biochemistry or you've been led astray by the cognitive bias of anyone of the million "eat this diet"-authors.

First you (thankfully) move away from saying our body definitely needs carbs to agreeing that 40% of these carb needs can be met by ketones.

First let's get some terminology straight (especially since you seem to advocate "accuracy"). "Ketones", any old ketone, is not usable by the body. Your body can only use "[URL BODIES
[/URL]. Of these only http://en.wikipedia.org/wiki/Beta-hydroxybutyric_acid" can be shipped around the body for a potential fuel source, where it is converted to acetoacetone then undergoes 1 round of B-oxidation to make 2 acetyl-CoAs. AcCoA is the ONLY ketone your body can use for energy production, which involves TCA cycle.

Secondly; I pointed out that your body can use ketone bodies to meet some of the brains energy demands in my first post. SOME being the operative word here, accounting for 30-40%. Aside from that, the brain MUST have glucose. Your brain cannot meet its total energy demand for energy through KBs. IT WILL DIE WITHOUT GLUCOSE.

The brain prefers glucose to all other energy sources, just as intestinal epithelium prefers to use Gln. Different tissues preferentially select carbon sources over others and removal of said sources leads to dysfunction of the tissue (and in some cases, such as the brain, to tissue failure).

You further agree that the remaining can be met by gluconeogenesis, although you quibble over whether all compounds are glucogeneic. I can live with you disagreeing over that. As long as we've busted the myth that the brain can function only on carbs and all those carbs have to come from diet. And we've busted that big time, thanks

Again, as I pointed out, your brain must glucose. Gluconeogenesis is the livers process to increase blood glucose levels for the sake for your brain (and RBCs). It doesn't matter whether you get that glucose through ingestion (the body's preferred way) or through catabolism of other useful substances. The whole reason the body has gluconeogeneic enzymes is because of the brains requirement for glucose (a carb).

Again, the most efficient way for the body to regulate blood glucose is through ingestion of glucose and storage as liver glycogen. If you disagree with this, please study http://en.wikipedia.org/wiki/Glycogen_storage_disease" .

And re: the cliched claim that "amino acid (protein) metabolism leads to increased BUN levels, which negatively affect both your kidneys and your liver", Evidence please.

This is basic renal physiology. As I pointed out above, to PS, increasing BUN, blood ammonia and blood acidosis stresses the kidneys, it increases their energy demands and causes long term changes to protein expression (namely NE3 and other such exchangers).

As Hamster pointed out, its evident in people with decreased glomular function that high protein diets in individuals in diseased states suffer more because of this. As to the effect on "healthy" people, the long term trends remain to be seen. Again, I'm not advocating "against" protein as you seem to suggest. The only one here that seems to advocating (in a rather uninformed manner) against a "culprit" macronutrient are these get rich quick dieters. The bottom line is, your body needs all macronutrients to maintain a healthy balance.

Again, if you want a healthy diet, try and emulate what we evolved to eat.

You also agree that there is a difference between ketosis and ketoacidosis. Thank you. Most people who shudder at the word ketosis are misplacing their shuddering by understanding ketosis as ketoacidosis.

For starters "most people" aren't aware of ketosis or ketoacidosis even are, so I fail to how they would "shudder". Secondly, I never said "ketosis" is "bad"-It is simply a reflection of the biochemistry of your metabolism. Namely, that you are doing elevated fatty acid catabolism.

Elevated KBs isn't the "natural state" of the human body, it is an adaptation to decreased nutrition from starvation. KB levels don't rise to measurable amounts till around ~48h without proper nutritional needs.

But you seem too think that ketoacidosis is some progressively worse form of ketosis, which is not entirely correct.

Ketoacidosis is the "outcome" of extended elevation of KBs in the blood plasma. This can result from a number of pathological conditions or from starvation conditions.

BTW here is a study that shows how "dangerous" ketosis actually is
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2716748/

Ketosis is like having acidosis. It is simply a reflection of the underlying biochemistry taking place. It isn't "good" or "bad", it simply is. It can be (just like acidosis or glycosuria or hypernatremia, etc) an indicator of biochemical processes in disequilibrium or potential problems yet to come (such as you're starving!). In itself it means little without a full history and clinical scenario.

Ketones are a byproduct of fat metabolism, so if you follow any diet and lose weight (or lose weight due to other reasons), you will produce ketones.

If by "ketones" you mean AcCoA then sure.

Maybe all the metabolic processes that lead to ketone production in ketoacidosis are present in ketosis, yet ketosis will not lead to an acidotic condition.

Here's a lovely link that explains it well.

BOTH ketosis and ketoacidosis are the result of elevated b-hydroxybuterate (and too a lesser extent acetone and acetoacetone) levels in the blood. The latter is a result of a pathological state of ketosis. Or in other words, in very elevated levels of those KBs.

I don't need a "blog-spot" to explain them to me. As I pointed out in my "about me" post, I am a medical student, I've studied them more in depth than is offered on the "blog-spot".

Diabetic Ketoacidosis (DKA) is seen primarily in patients with type 1 diabetes. The incidence is roughly about 3% of type 1 diabetic patients going into ketoacidosis when their pancreas first shuts down, and they are first diagnosed as diabetic. It can occur in type 2 diabetic patients as well if blood sugar is very uncontrolled. It is a serious condition that occurs in uncontrolled diabetics when their blood sugar is extremely high AND the bicarbonate is low (<15 mEq/L), AND they are in acidosis (pH <7.30). A low carb diet would be an excellent idea to stabilize blood sugars.

Low carb diets work in type II diabetics because in type II diabetics the natural response to insulin is still there, just resistant. By utilizing a low carb diet, you can increase the body's response to insulin and promote glucose-balance.

Even more important than "low carb diets" in type II'ers is low caloric diets.

Low calorie or low carb diets are NOT appropriate treatments for type I diabetics. Who have no basal insulin because of (most often) an autoimmune response against the pancreatic-beta cells. These people need insulin administered, and the different types of insulin (there are different biological half-life types, such as "long lasting insulin") and have to control their diets based on the peak-presence of insulin. However, with fast acting insulin and insulin-pumps becoming more prominent over the last 25 years, many of these people are free to lead a more "normal" life-style and diet. Though, since many of them tend to error on the side of hypoglycemia, it remains to be seen the long term effects of such a state and over the next couple of decades we'll undoubtedly see what affects this has, if any.

I'm not sure why you are on a hiatus against "carbs" other than being suckered by diet gurus. For the 3rd time in one day, if you want a healthy diet, emulate what we evolved to eat. Which certainly includes carbs. The problems Americans are faced with isn't the "evil" carb, its the excesses of macronutrients and calories in general, coupled with a relatively inactive life-style. We want a lot for little investment and unfortunately, health doesn't work that way.

 

[Proton Soup]

Its not only BUN levels, but blood acidity in general. On most western diets we are slightly acidotic because of increased protein consumption. Your kidneys are built with an excess of nephrons, which in most cases mitigate this acidosis. But the general effect is to require your kidneys to work harder.

Increases in protein metabolism also lead to increases in ammonium excretion (through tubule lumen hydrogen ion loading), which is good because it reduces ammonia levels, but at the same time reduces concentration of final urine (not provisional, which remains isosmotic) and again requires more work on the kidney.

The problem with kidney disease (as apparent to anyone who's studied renal physiology) is the excessive GFR (glomular filtration rate), which glomular function doesn't take a "dive" until we've reached around 15% of our glomular function.

This is pretty basic medical renal physiology. For more information, I'd recommend https://www.amazon.com/dp/007161303X/?tag=pfamazon01-20.

*Just a note, I'm not saying "protein diets" are "bad", just as I was not saying that "carb diets" are "bad". We're far to individual for that. I will say, what I said a while ago, that if you really want a healthy diet you should seek to emulate that diet we evolved to eat. Namely, complex plant carbs in variety, lean meats and simple animal carbs and healthy animal fats. As Yanick pointed out though, the discipline required to adhere to such "stone-age" diets, is too much for most American's (and Westerners) in general, who live by the American motto of miracle cure-all's and get rich quick schemes.

The reality in our modern setting is that hard work and discipline are required to maintain health, there is no free lunch.

i'm not here to promote hi-carb/lo-carb/paleo/keto/etc. for the record, my personal bias would be a pretty balanced diet of lean meats, veggies, nuts, dairy, whole grains, fruits, fish, legumes, etc. with a good bit more exercise, and a slight bit more protein-% than the typical modern american diet.

but the protein myth of destroying your kidneys is just that. and what constitutes "high" protein depends on who is perpetuating the myth (promoting veganism say, versus attacking bodybuilding or paleo nutters). at this point, as you guys have pointed out, all we have is a bunch of speculation, save some http://www.ncbi.nlm.nih.gov/pubmed/19917783" that no doubt clouds the matter in the minds of docs that have formed a bias.

it would also be nice if the people that want to perpetuate the "protein is bad for your kidneys" myth would give a recommended upper limit, say in something like grams_protein/kilogram_bodyweight/day.

 

[Siv]

I'm not sure why you are on a hiatus against "carbs" other than being suckered by diet gurus. For the 3rd time in one day, if you want a healthy diet, emulate what we evolved to eat. Which certainly includes carbs. The problems Americans are faced with isn't the "evil" carb, its the excesses of macronutrients and calories in general, coupled with a relatively inactive life-style. We want a lot for little investment and unfortunately, health doesn't work that way.

Wow, you're saying everything Gary Taubes does He is not a diet guru BTW. His only interest in nutrition arose because someone pointed him out to the pathetic quality of the research there. Since you claim to be such an expert, I am sure you know about Ancel Keyes and the terrible myths he helped establish, which are still the key tenets used by the establishment and doctors. Its Taubes who opens our eyes to the tons of real research and evidence there. Like I've said zillion times on this very forum, his book is like a compilation of research.

And most of the blogs I reference are written by doctors and experts in biochemistry. None of them are diet gurus. So even a well-intentioned medical student can learn something there

We evolved to eat a lot of meat. And a few berries and tubers.
There were no grains and no refined flour (or other refined carbs), sugar or HFCS for more than 90% of our evolutionary history. In fact, right upto the early 1900s, the common sense approach of weight loss was to avoid refined carbs and sugar. Its only after Keyes and a few others started spewing nonsense and the media gobbled it up that the tenets changed.

 

[Siv]

What we really need is to look at the rates of chronic kidney disease and ESRD among the elderly (60+) and correlate them with (possibly self-reported) average lifetime protein consumption levels. We already know that a high-protein diet accelerates the progression from mild renal insufficiency to chronic kidney disease (link above) and from CKD to ESRD (http://ndt.oxfordjournals.org/content/15/12/1986.abstract). All we need is to connect the dots: even assuming that renal insufficiency is equally likely to occur among Atkins followers and carb eaters, the former group is far more likely to end up on dialysis. But I'm not aware of such study. And the myth of safety of high protein diets lives on.

On the contrary what lives on is your myth, that high protein is somehow harmful. Unless you have some kidney problems to start with, there is absolutely no evidence that high protein is bad for you.

 

[bobze]

i'm not here to promote hi-carb/lo-carb/paleo/keto/etc. for the record, my personal bias would be a pretty balanced diet of lean meats, veggies, nuts, dairy, whole grains, fruits, fish, legumes, etc. with a good bit more exercise, and a slight bit more protein-% than the typical modern american diet.

but the protein myth of destroying your kidneys is just that. and what constitutes "high" protein depends on who is perpetuating the myth (promoting veganism say, versus attacking bodybuilding or paleo nutters). at this point, as you guys have pointed out, all we have is a bunch of speculation, save some http://www.ncbi.nlm.nih.gov/pubmed/19917783" that no doubt clouds the matter in the minds of docs that have formed a bias.

it would also be nice if the people that want to perpetuate the "protein is bad for your kidneys" myth would give a recommended upper limit, say in something like grams_protein/kilogram_bodyweight/day.

Well I don't know that is so much of a myth, as just a non-sequitur in the grand scheme of things; ie your more likely to die of something else before protein adversely affects your kidneys, baring degenerative renal disease. Remember we actually only need about 15% of our nephrons and since each kidney has about 10⁶ nephrons, loosing some is hardly consequential.

It is well known however that (again reference Vander's or another appropriate and authoritative source on renal physiology) that after increases in protein metabolism (such as eating a meal) glomerular hyperfiltration happens. Hyperfiltration leads to golmerular sclerosis. Namely because AA concentrations results in the transient elevation of GFR. Hence all those nephrologists proscribing low protein diets to patients with renal disease.

However, as I pointed out, to a healthy individual this doesn't appear to be a big deal. The hyperfiltration is only transient and lasts for an hour or two. So that any sclerosis that does occur because of protein loading, has little effect in the grand scheme of things (a few nephrons, who needs 'em?)

Remember, you can actually give away a kidney which is pretty amazing (probably not as amazing of the number of organs you don't need to survive. I mean really think about what do you need? A brain, which some people do fine without, a left ventricle, an atria, a kidney, a stomach, a third of a small intestine, a pancreas, a lung and half a liver--That's pretty interesting). So because of the excessive glomerular function, high protein diets (within a realm of reason) are probably of little concern (again, you're more likely to die from something else before it adversely affects glomerular efficiency).Edit to add; it would be an interesting "homework" assignment if anyone could find a cohort study comparing renal disease in people in the west (high protein diets) and people in developing countries (low protein diets). It would be interesting to note if the increase in life expectancy (something evolution clearly didn't plan for) is problematic with nephron destruction over the longer life span. With such a excessive amount of nephrons, I still would doubt that our GFR and glomerular function would be adversely affected--I don't think we've increased life-spans to such excessive amounts yet. Maybe one day, 10 generations from now, it will be more of a concern (assuming those future people can just make their own new kidneys

 

[bobze]

On the contrary what lives on is your myth, that high protein is somehow harmful. Unless you have some kidney problems to start with, there is absolutely no evidence that high protein is bad for you.

See the post above. Please reference a renal physiology textbook. Not a blog.

 

[bobze]

Wow, you're saying everything Gary Taubes does He is not a diet guru BTW. His only interest in nutrition arose because someone pointed him out to the pathetic quality of the research there. Since you claim to be such an expert, I am sure you know about Ancel Keyes and the terrible myths he helped establish, which are still the key tenets used by the establishment and doctors. Its Taubes who opens our eyes to the tons of real research and evidence there. Like I've said zillion times on this very forum, his book is like a compilation of research.

That you believe medical nutrition is based solely on the work of Keys shows to the trained eye how far removed from the institution of medicine or science you are. Like any scientist to pioneer a field (Darwin for instance), Keys got some hits and some misses. That cardiovascular disease is related to cholesterol, cortisol and many other risk factors has been shown without a doubt. Other things, he missed on.

Taubes is a physicist, for the same reason I don't take my children to to a biochemist to get their teeth cleaned, I don't "read Taubes" for advice on nutrition.

And most of the blogs I reference are written by doctors and experts in biochemistry. None of them are diet gurus. So even a well-intentioned medical student can learn something there

Thanks, but I'll take my 200,000 dollars or so in education and raise you one. When they introduce those "well written" blogs into medical curriculum I'll be sure to check them out.

We evolved to eat a lot of meat. And a few berries and tubers.
There were no grains and no refined flour (or other refined carbs), sugar or HFCS for more than 90% of our evolutionary history. In fact, right upto the early 1900s, the common sense approach of weight loss was to avoid refined carbs and sugar. Its only after Keyes and a few others started spewing nonsense and the media gobbled it up that the tenets changed.

Again, showing you are well removed. We didn't evolve to eat a lot of meat. Only recently in history has our diets included so much protein. We evolved to eat seasonal varied diets of starches (carbohydrates, from wild grains, fruits, etc) lean meats (not all that often) and animal fats (again not all that often). You are of course welcome to go spend some time living in any of the tribal villages removed from modern society and feast upon this bounty yourself.

Or, maybe you should spend some time in an anthropology library...

 

[Yanick]

Wow, you're saying everything Gary Taubes does He is not a diet guru BTW. His only interest in nutrition arose because someone pointed him out to the pathetic quality of the research there.

So he felt that the research in the area of nutrition was pathetic so instead of trying to do his own research to advance the field he went out and cherry picked the research that allowed him to write a book and make tons of money? Are you not seeing the paradox in this?

We evolved to eat a lot of meat. And a few berries and tubers.

Actually we evolved as omnivores. Meaning eat whatever you can get your hands on because humans, as purely physical specimens, are pretty low on the food chain.

Don't believe me? Compare your teeth to a true carnivore, like a lion. Notice a difference?

 

[Borek]

Please everyone - it was a nice read up to now, but I feel like it is getting emotional.

 

[Siv]

Looks like people have a problem with Gary Taubes. Maybe because he is not handsome enough. Why else would people dismiss him without even reading his book ?

Maybe they have something against science writers. Or only a science writer who has won the Science in Society Award of the National Association of Science Writers three times and was awarded an MIT Knight Science Journalism Fellowship for 1996-97.

Is science practised differently in nutrition than in other fields ?
I know the quality of science in nutrition is pathetic but last time I checked science worked the same way

Read his book and refute the tons of evidence in it. Ad hominem continues to be a logical fallacy.

 

[Siv]

That you believe medical nutrition is based solely on the work of Keys shows to the trained eye how far removed from the institution of medicine or science you are. Like any scientist to pioneer a field (Darwin for instance), Keys got some hits and some misses. That cardiovascular disease is related to cholesterol, cortisol and many other risk factors has been shown without a doubt. Other things, he missed on.

The cholesterol hypothesis is an extremely controversial one. Are you sure you are up to date on that ?!

Again, showing you are well removed. We didn't evolve to eat a lot of meat. Only recently in history has our diets included so much protein. We evolved to eat seasonal varied diets of starches (carbohydrates, from wild grains, fruits, etc) lean meats (not all that often) and animal fats (again not all that often). You are of course welcome to go spend some time living in any of the tribal villages removed from modern society and feast upon this bounty yourself.

Or, maybe you should spend some time in an anthropology library...

Ha ha, nice joke.
Read my quote -

We evolved to eat a lot of meat. And a few berries and tubers.
There were no grains and no refined flour (or other refined carbs), sugar or HFCS for more than 90% of our evolutionary history. In fact, right upto the early 1900s, the common sense approach of weight loss was to avoid refined carbs and sugar. Its only after Keyes and a few others started spewing nonsense and the media gobbled it up that the tenets changed.

This topic is a controversial one too. The less meat and no fat theory is just one of them around. We did not eat mostly vegetable and fruit matter because our bodies are designed very differently from herbivores. Also, fruits and vegetables pre-dept stores contained a lot less starch and sugar than it does now.
The meat might have been leaner cuts, but HGs more than made up for the fat content of the muscle by eating brains, organs etc.

Here's an interesting journal article (unfortunately only abstract is free, but the full version has been discussed in some of the blogs you hate so much )
http://www.journals.uchicago.edu/doi/abs/10.1086/381662

From the above, researchers have determined early humans’ development of “meat-adaptive” genes that helped humans uniquely process the natural fat and (in those days) inevitable parasites in meat, an ability that isn’t found to the same degree in other related primates. Once humans began consuming meat as a central diet staple some 2 ½ million years ago, the species experienced a surge in life span and competitive benefits in the fight for survival.

Here's another interesting paper by Loren Cordain (yes I know, you most likely hate him too, but he is a Ph.D in Health and Exercise ... and knows his anthropology )
http://www.thepaleodiet.com/articles/2006_Oxford.pdf

Beginning approximately 2.6 Mya, the hominin species that eventually led to Homo began to include more animal food in their diet. A number of lines of evidence support this viewpoint. First, Oldowan lithic technology appears in the fossil record 2.6 Mya (Semaw et al., 2003), and there is clear cut evidence to show that these tools were used to butcher and disarticulate animal carcasses (Bunn and Kroll, 1986; de Heinzelin et al., 1999). Stone tool cut marks on the bones of prey animals and evidence for marrow extraction appear concurrently in the fossil record with the development of Oldowan lithic technology by at least 2.5 Mya (de Heinzelin et al., 1999).

In addition to the fossil evidence suggesting a trend for increased animal food consumption, hominins may have experienced a number of genetic adaptations to animal-based diets early on in our genus’s evolution analogous to those of obligate carnivores such as felines. Carnivorous diets reduce evolutionary selective pressures that act to maintain certain anatomical and physiological characteristics needed to process and metabolize high amounts of plant foods. In this regard, hominins, like felines, have experienced a reduction in gut size and metabolic activity along with a concurrent expansion of brain size and metabolic activity as they included more energetically dense animal food into their diets (Leonard and Robertson, 1994; Aiello and Wheeler, 1995; Cordain, Watkins, and Mann, 2001). Further, similar to obligate carnivores (Pawlosky, Barnes, and Salem, 1994), humans maintain an inefficient ability to chain elongate and desaturate 18 carbon fatty acids to their product 20 and 22 carbon fatty acids (Emken et al., 1992). Since 20 and 22 carbon fatty acids are essential cellular lipids, then evolutionary reductions in desaturase and elongase activity in hominins indicate that preformed dietary 20 and 22 carbon fatty acids (found only in animal foods) were increasingly incorporated in lieu of their endogenously synthesized counterparts derived from 18 carbon plant fatty acids. Finally, our species has a limited ability to synthesize the biologically important amino acid, taurine, from precursor amino acids (Sturman et al., 1975; Chesney et al., 1998), and vegetarian diets in humans result in lowered plasma and urinary concentrations of taurine (Laidlaw et al., 1988). Like felines (Knopf et al., 1978; MacDonald, Rogers, and Morris, 1984), the need to endogenously synthesize taurine may have been evolutionarily reduced in humans because exogenous dietary sources of preformed taurine (found only in animal food) had relaxed the selective pressure formerly requiring the need to synthesize this conditionally essential amino acid.

However, there are a number of lines of evidence which suggest more than half (>50%) of the average daily energy intake for most Paleolithic hominin species and populations of species was obtained from animal foods.
Richards, Pettitt, and colleagues (2000) have examined stable isotopes (δ13C and δ15N) in two Neanderthal specimens (~28,000—29,000 years BP) from Vindija Cave in northern Croatia and contrasted these isotopic signatures to those in fossils of herbivorous and carnivorous mammals from the same ecosystem. The analysis demonstrated that Neanderthals, similar to wolves and arctic foxes, behaved as toplevel
carnivores, obtaining all of their protein from animal sources (Richards, Pettitt, et al., 2000). A similar analysis was made of five Upper Paleolithic Homo sapiens specimens dated to the Upper Paleolithic (~11,700–12,380 years BP) from Gough’s and Sun Hole Caves in Britain (Richards, Hedges, et al. 2000). The data indicated these hunter-gatherers were consuming animal protein year-round at a higher trophic level than the artic fox.
Both studies by Richards, Hedges, and colleagues (2000) and Richards, Pettitt, and colleagues (2000) could be criticized as not being representative of typical hominin
diets, as these two species lived in climates and ecosystems that fostered an abundance of large, huntable mammals, which were preyed on preferentially. Additional clues to the typical plant-to-animal subsistence ratio in Paleolithic hominin diets can be found in the foraging practices of historically studied huntergatherers.
Our analysis (fig. 19.2) of the Ethnographic Atlas data (Gray, 1999) showed that the dominant foods in the majority of historically studied hunter-gatherer diets were derived from animal food sources (Cordain et al., 2000). Most (73%) of the world’s hunters-gatherers obtained >50 percent of their subsistence from hunted and fished animal foods, whereas only 14 percent of worldwide hunter gatherers obtained >50 percent of their subsistence from gathered plant foods. For all 229 hunter-gatherer societies, the median subsistence dependence on animal foods was 56 percent to 65 percent. In contrast, the median subsistence dependence on gathered plant foods was 26 percent to 35 percent (Cordain et al., 2000).

Phew, that's a lot of evidence !

 

[cosmos 2.0]

We evolved to eat a lot of meat. And a few berries and tubers.
There were no grains and no refined flour (or other refined carbs), sugar or HFCS for more than 90% of our evolutionary history. In fact, right upto the early 1900s, the common sense approach of weight loss was to avoid refined carbs and sugar. Its only after Keyes and a few others started spewing nonsense and the media gobbled it up that the tenets changed.

Type of food people eat varies from region to region. Even the last five to ten thousand years , when agriculture had made grains a staple diet people began adapting to it, so this also is part of our evolutionary history. our body can use carbs effectively as fuel. Refined carbs are just as bad as trans and hydrogenated fats or red meat. There is a trend to blame one type of diet for all the health problems. It has happened before, it is happening now.

 

[cosmos 2.0]

From the above, researchers have determined early humans’ development of “meat-adaptive” genes that helped humans uniquely process the natural fat and (in those days) inevitable parasites in meat, an ability that isn’t found to the same degree in other related primates. Once humans began consuming meat as a central diet staple some 2 ½ million years ago, the species experienced a surge in life span and competitive benefits in the fight for survival.

As i said in the previous post, we adapted to a diet of grains thousands of years ago. So it is part of our evolution history. I do not know how we can conclude what a particular diet did or did not do to a species. I think it becomes pure speculation when you are talking about a species two million years ago.

 

[Siv]

cosmos 2.0, we cannot undo more than 90% of our evolutionary history that easily. The harm that grains do is well documented.

 

[bobze]

The cholesterol hypothesis is an extremely controversial one. Are you sure you are up to date on that ?!

You'll note that that I said cholesterol is correlated to cardiovascular disease. I never said it is the cause or sole cause of cardiovascular disease. That its correlated to cardiovascular disease (along with many other factors) there is no doubt. Please don't make "claims" of what I'm saying.

Ha ha, nice joke.
Read my quote -
This topic is a controversial one too. The less meat and no fat theory is just one of them around. We did not eat mostly vegetable and fruit matter because our bodies are designed very differently from herbivores. Also, fruits and vegetables pre-dept stores contained a lot less starch and sugar than it does now.
The meat might have been leaner cuts, but HGs more than made up for the fat content of the muscle by eating brains, organs etc.

Here's an interesting journal article (unfortunately only abstract is free, but the full version has been discussed in some of the blogs you hate so much )
http://www.journals.uchicago.edu/doi/abs/10.1086/381662

From the above, researchers have determined early humans’ development of “meat-adaptive” genes that helped humans uniquely process the natural fat and (in those days) inevitable parasites in meat, an ability that isn’t found to the same degree in other related primates. Once humans began consuming meat as a central diet staple some 2 ½ million years ago, the species experienced a surge in life span and competitive benefits in the fight for survival.

Here's another interesting paper by Loren Cordain (yes I know, you most likely hate him too, but he is a Ph.D in Health and Exercise ... and knows his anthropology )
http://www.thepaleodiet.com/articles/2006_Oxford.pdf





Phew, that's a lot of evidence !

Neither of these disagree with anything I've said. Did we evolve to eat more meat than other great apes? Yes, we sure did. Did we "evolve to eat lots meat"? No we sure didn't, as Yanick pointed out, we are omnivores and evolved on an omnivorous diet. You'll note that we (in the west) eat more protein now than at any other time of our history. You'll also note that our bodies (both physiologically and anatomically) are not the bodies of carnivores, rather omnivores. Your first article is irrelevant to your claim that we evolved to eat "lots of meat". Here's the conclusion since you didn't seem to actually read the study, only the abstract;

The evolution of the extended human life
span was achieved through selection operating
on many developmental pathways. The
chimpanzee taste for meat could have set the
stage for the evolution of genes that allowed
increased fat consumption without hypercholesterolemia.
The evident sensitivity of captive
chimpanzees to hypercholesterolemia and
ensuing vascular disease, if present in the
shared ancestor, required mutations that
allowed emerging humans to have a far richer
diet and to extend their development schedule.
We argued that the evolution of the
human apoE3 and other candidates for meatadaptive
genes enabled the shift from an herbivorous
ape diet to the more omnivorous
diet of hominids, while also enabling a major
increase in life span.
We would, of course, like to know how life
spans evolved during these changes. The fossil
record, unfortunately, tells little about
adult life spans. The schedules of dental
development suggest that prolonged postnatal
development was relatively recent. Growth
patterns in tooth enamel indicate that Neandertal
dental development approximated
that of modern humans and was slower than
in australopithecines and early humans (H.
habilis and H. ergaster) (Dean et al. 2001;
Moggi-Cecchi 2001). On this basis, Neandertals
and anatomically modern prehistoric
humans might have had longer postmaturational
nurture than early humans or australopithecines,
but we can say little about life
expectancy.
The chimpanzee genome projects (Cyranoski
2002) are being augmented by functional
genomics. As an alternative to in vivo
studies on captive chimpanzees that face
strong ethical objections (NHGRI 2002), we
note that cultured cells (fibroblasts, lymphomas,
and blood cells) are available to study
human-chimpanzee differences (e.g., Karamen
2003). In vitro models can also be used
to study gender-hormone interactions on cell
metabolism, which are indicated by the sensitivity
of female chimpanzees to obesity (Steinetz
et al. 1996). Expression profiling for species
differences in response to dietary and
stress factors could identify genes that confer
protection against chronic diseases, some of
which might also facilitate the greater life
spans of humans. At the same time, as elegant
technology is applied to human evolution,
there is a major need to study the natural history
of aging in the endangered wild chimpanzees
and to identify which aspects

Again, we certainly evolved to eat more meat than chimps, that doesn't mean we evolved to eat "lots of meat". The article deals with how gene changes for that increased meat consumption had to have happened to mitigate the potential dangers of higher fat diets...

 

[Siv]

I would consider more than 50% as "lots of meat", but if that's just a quibbling over semantics, so be it. We are in agreement then.

In any case, its then quite obvious that our evolutionary diet was a low carb one. Not zero-carb, no (and I never said that) but definitely low carb.

 

[Yanick]

Last comment from me in this thread and I'm done because this particular conversation may turn ugly at any moment.

I have not, and doubtfully ever will, read the Taubes book. See he, and all the other paleo/low carb nuts, make money doing this. It is their career. I cannot afford myself the time to sit around reading papers all day to refute all the evidence put forth by them. That is not my job, I don't make any money doing it, it will not further my career, therefore I am not going to start throwing papers, blogs and abstracts around with you (I have to do some experiments which are new to me, as well as study for midterms/finals, spend time with the better half and try to squeeze sleep in there somewhere).

The bottom line is that what these guys are saying is not really 100% wrong therefore you can't exactly refute everything they say. I mean think about it. How many overweight/obese or even regular people do you know that won't benefit from eating less processed foods, increasing vegetable intake and doing some consistent exercise?

The problem I have with these guys is the fact that they attribute half of the world's problems to a single food group. It is just unforgivable for a scientist to go around saying that X causes cancer, obesity, laziness, global warming, war, poverty etc. I've seen too many of these "eat this, not that" "this is good, that is bad" types of books. The former is actually a book mind you, my buddy has it and it tells you to eat McDonalds hamburgers over Burger King (or something like that) because they have something like 5g less fat.

If you want to live your life "paleo style," go get a spear and a loincloth and live in the forest, eating whatever you can catch and gather.

See the thing that most of these gurus don't tell you is that losing weight and maintaining a healthy lifestyle has to include a multitude of factors. They include eating less in general (I'm speaking of overweight people here, obviously someone who is 6 foot and 100 pounds probably needs to eat up!), staying away from processed foods, eating more fruits and vegetables, getting consistent exercise, staying hydrated, coping appropriately with stress and the list goes on and on, though I think I got the big ones.

One of the most important things, IMO, is really the ability to let go every so often and just enjoy yourself. Drink some booze, eat a pizza, slurp down HFCS if that is your thing. Do whatever it is that makes you feel good and allows you to blow off some steam and relax. Because honestly, if there is truly one factor that slowly kills everyone, that is the stress response. You can go read "Why Zebras Get Ulcers" by Dr. Robert Sapolsky. Now that's an amazing book! The important thing about 'letting go' though is that you have to be able to control yourself and make that a minor occurrence in your life.

This is getting into the realm of psychology/philosophy but I'll leave you with this little tidbit of info, which took me about a decade of extreme behavior to realize (and in some ways I'm still trying to apply it). Everything in life has its place. The key to living healthy and happy is finding a balance between the almost infinite amount of variables which affect your life. That's all I have to say on this subject.

EDIT to add: If you really want to learn some physiology as it relates to nutrition, you should check out Lyle McDonald. That guy really knows his stuff, stays on top of the latest research in weight management and, my favorite part about him, is not afraid to admit that his views change when the scientific landscape changes (he's pretty straight forward about it too, sometimes a bit too straight forward [anyone who frequents or used to frequent his site(s) knows what I'm talking about]).

 

[Siv]

One word Yanick. Evidence.

 

[Greg Bernhardt]

http://www.nytimes.com/2010/11/21/magazine/21Epilepsy-t.html

Interesting related article

 

[Siv]

Hey, thanks Greg.

Here's one more recent article from Dana Carpender's blog

http://www.foodnavigator-usa.com/Sc...ase-heart-disease-risk-say-nutrition-experts/

Excerpts:

During a symposium called “The Great Fat Debate: Is There Validity In the Age-Old Dietary Guidance?” at the American Dietetic Association’s (ADA) Food and Nutrition Conference and Expo, four leading experts presented evidence suggesting that low fat diets may be less healthy than those containing at least a moderate amount of fat. In particular, all four agreed that replacing saturated fat with carbohydrates – as has been widely recommended in the United States – is likely to raise the risk of cardiovascular disease.

Chair of the Harvard School of Public Health’s nutrition department Dr. Walter Willett takes this even further.


“If anything, the literature shows a slight advantage of the high fat diet,” he said. “The focus on fat in dietary guidelines has been a massive distraction…We should remove total fat from nutrition facts panels on the back of packs.”

He added that while the pervasive dietary guidance given to consumers has been to eat fats sparingly, to load up on starch and eat non-fat products, “the food industry quickly realized sugar was cheaper than fat and laughed all the way to the bank.”

Its time for more research into the subject. Lots more open-minded research. Not funded by the food or drug industry.

 

[dreiter]

I don't know why there is even a low-carb/high-carb debate! The large majority of studies I have seen point to a balanced diet of carbs, fats, and proteins. As a general rule, extremes are never good. Naturally we want to intake the foods that science has found to be the healthiest for us to eat. Now when you look at a steak and compare it to an orange, you see a protein and a carb. But you also see the nutrients contained in those calories. An orange has many more vitamins, minerals than the steak does, and also contains fiber and phytochemicals, both of which have a long history of promoting human health.

So what is healthier, a carb or a protein? Well obviously you don't want to eat just one, but I would certainly suggest eating many more oranges than steaks...