low-carbohydrate, high-protein diets may not be healthy in the long run

[Samuel]

EUFIC Later Science

Low carb, high protein diets may be unhealthy in the long term

A large observational study has suggested that low-carbohydrate, high-protein diets may not be healthy in the long run

EUFIC.org - August 22, 2007

Low-carbohydrate, high-protein diets (an example of such a diet could be the Atkins diet), are popular for weight control. Short-term intervention studies suggest that these diets produce a similar weight loss to traditional high-carbohydrate, moderate-protein diets. However, a large observational study has suggested that low-carbohydrate, high-protein diets may not be healthy in the long run.

Researchers from Greece used data from the multi-centred EPIC trial (European Prospective Investigation into Cancer and Nutrition) to investigate relationships between mortality and dietary composition. 22,950 healthy adults aged between 20 – 86 were followed between 1993 and 2003. Diets were recorded using a validated food frequency questionnaire.

It was found that there was significantly lower mortality risk for those adults with the highest carbohydrate intake, while diets richer in protein were associated with a non-significant higher risk of mortality. For subjects who followed a dietary pattern which combined the highest protein and lowest carbohydrate content within the sample, the risk of mortality increased. The authors suggest that these types of diets may not be a healthy option in the long-term.

For more information, see
Trichopoulou A et al (2007). Low-carbohydrate-high-protein diet and long-term survival in a general population cohort. European Journal of Clinical Nutrition, Vol 61, pp 575-581.

www.eufic.org (http://www.eufic.org/)

[ReginaW]

As I noted on my blog when I wrote about this study in May (it was originally released in November 2006 - and just keeps coming up again and again).....the finding is based on computer models, not real life eating patterns of those in the EPIC trial.

The researchers would have been better off publishing their findings from the absolute intake data and letting the data stand as it is rather than make various adjustments to convoluted extremes and try to make headlines. When you look at the data of absolute intakes - there is NOTHING.....only the modeled unreal tweaking found something.

Nice try though. Not news when it was first published and not news today!

[LarryAJ]

If there was any validity to this conclusion, then the Eskimos would never have survived, yet alone seem to have prospered considering the extreme harshness of their environment.

[doreen T]

Here's our original multi-page discussion about this .. http://forum.lowcarber.org/showthread.php?t=319032


Doreen

[FenwayGuy]

Thanks Doreen. I just read through that whole thread.

I have completed, in fact am now in my 2nd reading, Dr. Malcolm Kendrick's book, "The Great Cholestrol Con. The Truth About What Really Causes Heart Disease and How to Avoid It."

I have always been aware of statistics and how they can be manipulated, etc. but what I really got from his book is the true meaning of significant and nonsignificant. This "study" needless to say proves absolutely zilch.

[Wifezilla]

"There are three kinds of lies: lies, damned lies, and statistics." - Mark Twain

And besides, my food intake is higher in fat than protein. So "high-protein" can also be a misleading statement when it comes to low-carb.

[Gypsybyrd]

I realize there's a thread devoted to this already but my two cents here ...

It was found that there was significantly lower mortality risk for those adults with the highest carbohydrate intake, while diets richer in protein were associated with a non-significant higher risk of mortality. For subjects who followed a dietary pattern which combined the highest protein and lowest carbohydrate content within the sample, the risk of mortality increased.

Maybe I'm missing something but ... if one thing leads to a 'significantly lower mortality risk' then shouldn't the opposite lead to a 'significantly higher mortality risk'? (Keeping it within the context of carb v. protein intake. Of course, as pointed out - that doesn't take into account higher fat intake.)

[francisstp]

And besides, my food intake is higher in fat than protein. So "high-protein" can also be a misleading statement when it comes to low-carb.


Indeed. I'm always impressed by the narrow-mindedness of reporters who seem to only be aware of the Atkins diet and of no other low-carb approches.

Atkins is a high-fat diet by design, and DANDR does not put much emphasis on high protein content like the Eades' books do. Goddamn, it's called Protein Power for a reason!

[ruthla]

Even PP isn't a pure protein diet! On a typical day, I'm eating more grams of fat than grams of protein, and certainly more fat CALORIES than protein calories!

Even if they did find a population who fared worse on low carb than high carb, I'd like to know what they were actually eating: "Frankenfoods" full of synthetic chemicals and low in protein and nutrients? Or fresh meats and veggies?

[+35-65]

You know what is REALLY unhealthy in the long run? Being fat.

People need to do what works for them and not try to cram all of society into one size / one diet fits all. I saw my MD this am and I asked her what she thought of low carb. She asked me three questions:
1) are you taking any kinds of pills, chemicals, diet aids?
NO
2) are you eating more whole & natural foods rather than processed and manufactured to be low carb foods (i.e. Frankenfoods)?
YES
3) is it working and something you can do for the long haul?
YES

Then it is incredibly healthy for you.

[ReginaW]

Even PP isn't a pure protein diet! On a typical day, I'm eating more grams of fat than grams of protein, and certainly more fat CALORIES than protein calories!

Even if they did find a population who fared worse on low carb than high carb, I'd like to know what they were actually eating: "Frankenfoods" full of synthetic chemicals and low in protein and nutrients? Or fresh meats and veggies?

The biggest issue with the study is that they found NOTHING when they examined what people actually ate - they only found statistical significance when they played with the data and made up scenarios that didn't exist in real world eating patterns. Ugh - that's not science!

[cleochatra]

Atkins isn't even technically a high protein diet. It's really, if anything, a high fat diet, only medium proteinwise.

[ReginaW]

Atkins isn't even technically a high protein diet. It's really, if anything, a high fat diet, only medium proteinwise.

Or as Eades like to call it "adequate" protein :cool:

[pauleo]

The biggest issue with the study is that they found NOTHING when they examined what people actually ate - they only found statistical significance when they played with the data and made up scenarios that didn't exist in real world eating patterns. Ugh - that's not science!

I've only seen the abstract, and it seems you've seen the paper. How did they play with the data, and what scenarios did they make up?

[teaser]

"Short-term intervention studies suggest that these diets produce a similar weight loss to traditional high-carbohydrate, moderate-protein diets."
Actually, they usually kick the high carb diets butts.

[ReginaW]

I've only seen the abstract, and it seems you've seen the paper. How did they play with the data, and what scenarios did they make up?

Yes, I read the full-text of the publication and blogged about it back in May:

The Devil in the Details - Low-Carb High Protein Diet Kills (http://weightoftheevidence.blogspot.com/2007/05/devil-in-details-low-carb-high-protein.html)

A study - Low-carbohydrate–high-protein diet and long-term survival in a general population cohort - published in the May edition of the European Journal of Clinical Nutrition (originally available ahead of print, November 2006), concluded that "Prolonged consumption of diets low in carbohydrates and high in protein is associated with an increase in total mortality."

When I read the first publication of the study, back in November, I decided not to write about it since I was focused on penning articles about diabetes throughout National Diabetes Month and this study wasn't about diabetes. It remained on my pile of studies to consider, but as time passed, it seemed less and less important to write about. Now, with it hitting the print edition, and a renewed interest in the findings, it's time to take a look at what the researchers found and how they reached their conclusions.

Jake Young, who writes at Pure Pedantry, thought it worthwhile to take a look too. In summing up the design of the study, he wrote "[j]ust to cross the t's and dot the i's, they also control sex, age, years of schooling, smoking, BMI, physical activity, ethanol intake, and (in the data I am going to talk about) energy intake;" thinking, I believe, that adjusting for these confounding variables leads to higher quality conclusions.

Except in this case, adjusting for some of these variables led to a leap-of-faith extrapolation from the data because without making adjustments there was no significant finding to speak of, "[i]n model 2, the LC/HP score (absolute values) was positively associated with mortality, although the association did not reach statistical significance (P=0.14)." [emphasis mine]

In other words the association was statistically due to chance and therefore a null finding.

But, let's not let that get in the way of a good chance to find statistic significance!

Rather than take the data at face value for absolute intake (what people were eating), the researchers decided to adjust energy intake and considered this adjustment "as they should be, isocaloric..." to show how, after adjusting for energy intake variables things change.

And change they did.

With this one adjustment, statistical significance magically appears and now "mortality was significantly associated with reduction of energy-adjusted carbohydrate intake and nonsignificantly with increasing protein intake."

But still, how exactly to find protein problematic?

Ah, one more adjustment just might do it.

The researchers noted that their "model 3" "does not specify the complementary changes that have to be introduced for the preservation of total energy intake, when carbohydrates and proteins change." So, they created "model 4" and said it was "the most appropriate" since it was both isocaloric (adjusted for energy intake) and now adjusted to reflect changes from less carbohydrate and more protein.

Viola!

"In this model, increasing LC/HP score was significantly associated with mortality (P=0.001)."

Except, no one in the cohort ate like the adjusted diet, the statistically significant findings are not from real people eating real food (absolute intake), but are only found upon adjustment of energy and intake from protein and carbohydrate. The researchers justified this adjustment as necessary with "[i]ndeed, many of contemporary public health policies rely on extrapolations, so that if something is detrimental at a certain exposure level, its effect is likely to be more detrimental at a more extreme level."

Perhaps this is part of the problem with our public health policy? We're basing recommendations on extremes, extrapolated from adjusted models, rather than real world eating habits.

This is how the American Heart Association comes up with recommending less than 7% saturated fat to all Americans, even those at low risk for heart disease; they take data from studies that found no benefit from reducing saturated fat to 10% or less of calories and do the mental gymnastics to leap to an idea that benefit will be seen when saturated fat is less than 7% of calories. No data, just pure extrapolation and wishful thinking.

But, I digress...

There'd be nothing to talk about with this study if the researchers only went with their cohort and their habitual diet. Remember, when the absolute intake data was crunched, there was no statistically significant finding.

It's only after the researchers play with the data and make adjustments - adjustments outside the "norm" of their population cohort - into the extreme models, that they find significance.

In the real world you'll be hard pressed to find someone eating a diet within the extreme models they created. That's because the fundamental flaw in their model adjustment was the belief that decreasing carbohydrate means increasing protein. As the researchers noted in their paper, their adjustment model "relies on opposite changes of two nutrients with equivalent energy values and tends to be unrelated to total energy intake."

Simply put, the assumption was that reduction of carbohydrate translates to an isocaloric increase in protein.

The problem with this is that in the real world, increasing protein beyond what the body needs is extremely difficult due to satiety hormones that effectively shut down hunger when protein intake is adequate and carbohydrate is restricted. So the idea that one is effectively replacing carbohydrate with protein has a limit. A limit that seems beyond the grasp of this research group, who didn't seem to ask the important question - why did those with higher LC/HP (low-carb/high-protein) scores consume less calories than those eating a higher carbohydrate diet?

Rather than delve into this, they adjusted protein as if this group could and would consume more calories and more protein in a linear progression, adjusted their habitual intake to reach an isocaloric level comparable with their higher carboydrate counter-parts. But, because protein is such a sating macronutrient, this adjustment is not based on reality, but is purely hypothetical; and a hypothetical situation that one is likely to find impossible in a real world eating situation.

My take - the researchers would have been better off publishing their findings from the absolute intake data and letting the data stand as it is rather than make various adjustments to convoluted extremes and try to make headlines. Nice try though.

[ruthla]

Ah, yes. Low carb diets kill.

I'd say the long-term mortality rate is 100% for human beings no matter what diet you follow. ;)

[pauleo]

Yes, I read the full-text of the publication and blogged about it back in May:

The Devil in the Details - Low-Carb High Protein Diet Kills (http://weightoftheevidence.blogspot.com/2007/05/devil-in-details-low-carb-high-protein.html)


Thanks for reposting. I see how there are problems. Once you start adjusting the data to factor out confounding variables, you end up with a huge number of possible ways and combinations for doing that. It's not convincing to then single out just one of those possibilities and draw a hard conclusion from it. (That's a paraphrase that reflects how I understood your first criticism, so sorry if I mangled that part of your explanation in an incorrect way).

[gryfonclaw]

"There are three kinds of lies: lies, damned lies, and statistics." - Mark Twain




Whoa.

I'm getting my Bachelors in LIES!!!!!11eleventy

:lol:

[ojoj]

I so dont care about all these time and money wasting studies. The results can be bent to say anything you want them to!

You will always be able to find a study out there to say anything you want.

Just my thoughts!

[FenwayGuy]

I so dont care about all these time and money wasting studies. The results can be bent to say anything you want them to!

You will always be able to find a study out there to say anything you want.

Just my thoughts!

The following is slightly technical, but an excellent article on what ojoj has just stated.

http://medicine.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pmed.0020124&ct=1

At the very least, scroll down and read the Corollaries section. In particular make note of Corollary 5,

"The greater the financial and other interests and prejudices in a scientific field, the less likely the research findings are to be true."

Now, what does that sound like to you? The bias against low carb, the vested interests of food manufacturers in having us eat processed low fat, high carb food, not to mention Big Pharma who want us all hooked on statin drugs and the such for life?? Does that ring just a bit familiar??

[Demokat]

The following is slightly technical, but an excellent article on what ojoj has just stated.

http://medicine.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pmed.0020124&ct=1

At the very least, scroll down and read the Corollaries section. In particular make note of Corollary 5,

"The greater the financial and other interests and prejudices in a scientific field, the less likely the research findings are to be true."

Now, what does that sound like to you? The bias against low carb, the vested interests of food manufacturers in having us eat processed low fat, high carb food, not to mention Big Pharma who want us all hooked on statin drugs and the such for life?? Does that ring just a bit familiar??

I just read Malcolm Kendrick's 'The Great Cholesterol Con' and he basically said those studies used to support the lipid hypothesis are usually funded by Big Pharma or Agribusiness. Even so, they STILL can't directly link a high fat, high cholesterol diet with heart disease! It's like the oil companies sponsoring global warming research-you know that they're going to fund academic chairs, high-paid speaking engagements, etc. for those 'scientists' that toe the big oil line. This is especially true in the US, because big corporations can more easily corrupt scientific inquiry.

[fluffybear]

"There are three kinds of lies: lies, damned lies, and statistics." - Mark Twain

And besides, my food intake is higher in fat than protein. So "high-protein" can also be a misleading statement when it comes to low-carb.

So is mine and I eat mostly lean mean, fish and poultry. See my FitDay.

[FenwayGuy]

I just read Malcolm Kendrick's 'The Great Cholesterol Con' and he basically said those studies used to support the lipid hypothesis are usually funded by Big Pharma or Agribusiness. Even so, they STILL can't directly link a high fat, high cholesterol diet with heart disease! It's like the oil companies sponsoring global warming research-you know that they're going to fund academic chairs, high-paid speaking engagements, etc. for those 'scientists' that toe the big oil line. This is especially true in the US, because big corporations can more easily corrupt scientific inquiry.

Hey Demokat, Sox still up by 5. Keep the faith, big showdown in The Bronx next week :)

You are absolutely correct. Even when "they" cannot prove it (as Dr. Kendrick refers to them, ad-hoc hypotheses), they still scream so loudly so as to stifle dissenting opinion. Is that not what children do?? ;) .

I think that Malcolm Kendric has written a fantastic book, am now 3/4 of my way through the 2nd read. I can hardly wait for Gary Taubes "Good Calories, Bad Calories" due out in about a month. Funny thing, I purchased the two together from Amazon (those good deals they give you), and when GCC arrived, was rather blase about it. Then I log into my Amazon account, read some of the reviews and realize that this was not just a "throw in", but a terrific book in of itself.