Nina Teicholz and the BMJ mislead about the US Dietary Guidelines and low carbohydrate diets

 I’ve not blogged for a long while but Nina Teicholz seems to be making quite a splash with her latest BMJ piece 1 . The bit that stands out for me – in a piece which is supposed to be showing the weakness of the science behind the 2015 Dietary Guidelines Advisory Committee (DGAC) Scientific Report – is how this piece is used (and the BMJ) to attack recommended diets whilst surreptitiously promoting the idea that low carbohydrate diets are the hard done-by, ignored, always-the-bridesmaid-never-the-bride solution to our problems.

The sophist begins

Another important topic that was insufficiently reviewed is the efficacy of low carbohydrate diets.

Low carbohydrates are certainly an important topic, the DGAC states they have been of “public interest” 2 .

Again, the 2015 committee did not request a NEL systematic review of the literature from the past five years.

“Again” seems to imply a continued refusal to perform a review of the literature. This is of course misleading – a review specifically of low carbohydrate diets was unlikely to be performed in 2015 – because the DGAC is moving away from percentages of fat/carb/protein, and moving towards recommending dietary patterns1  (defined as “the quantities, proportions, variety or combinations of different foods and beverages in diets” 2).

In fact the NEL Systematic Review which Teicholz implies should have been carried for 2015 would have been rather difficult as the DGAC report clearly states that the low carbohydrate studies “generally did not meet the DGAC’s definition of a dietary pattern study unless a full description of the dietary pattern consumed was provided and appropriate methods were used to adjust for the confounding of foods and nutrients”.1

Teicholz in a roll here though, and continues with the DGAC are-ignoring-low-carbohydrate-diets spin

The report says that this was because, after conducting “exploratory searches” of the literature since 2000, the committee could find “only limited evidence [on] low-carbohydrate diets and health, particularly evidence derived from US based populations yet many studies of carbohydrate restriction have been published in peer review journals since 2000, nearly all of which were in US populations.

This is again misleading, as it makes it sound like the DGAC were simply dismissive of the benefits of low carbohydrate diets. However the report states that “The most evidence available focuses on low-carbohydrate diets and body weight. The 2010 DGAC examined the relationship between macronutrient proportion and various body weight outcomes“. The DGAC did in fact carry out a previous systematic review on weight loss, which they lean on in the 2015 report and state there are no further studies which change the conclusions.

This is probably why the 2015 DGAC report specifically identifies “Low-carbohydrate (initially less than 20 g/day carbohydrate) diet without formal prescribed energy restriction but realized energy deficit” as one possible method of weight loss.

So after her attempt to portray the DGAC as ignoring low carbohydrate diets, Teicholz offered some evidence of her own and a counter argument: there are lots of studies since 2000 showing benefit of low carbohydrate diets, you just need to look!

These include nine pilot studies11 case studies19 observational studies, and at least 74 randomised controlled trials, 32 of which lasted six months or longer (see table C on thebmj.com)

Table C: Published research on low carbohydrate diets 4 is full of bloat, and many of the studies cited are totally irrelevant to the questions the DGAC were considering. For example the first study on her list: did an inconclusive case study of 5 people with reflux 5 who self administered a low carbohydrate diet really merit formal review for the guidelines?

Do any of the cited studies in Table C provide evidence about the relationship between low carbohydrate dietary patterns and:

  • Risk of cardiovascular disease? (question 1)
  • Measures of body weight or obesity ? (question 2)
  • Risk of type 2 diabetes? (question 3)
  • Cancer? (question 4)
  • Risk of congenital anomalies? (question 5)
  • Risk of neurological and psychological illnesses? (question 6)
  • Bone health? (question 7)

Because they were the specific questions which the evidence needs to address, everything else is simply window dressing.

What about some of her other citations, the effect of low carbohydrate diets on epilepsy (numerous), migraines, physical activity, hunger, IBS, and rare conditions like Sturge Weber Syndrome? Are these generally applicable to the population and relevant to answering Questions 1-7?

The task of the DGAC was not to review what Teicholz calls the “many studies of carbohydrate restriction” and dredge for benefits. Does she believe an NEL should be carried out on every medical condition, just to satisfy her that some benefit of her favoured diet has not been cruelly overlooked?

In addition for someone preaching about high quality evidence why is she even listing case studies in Table C anyway? These would fail to meet the standards required for being considered in the NEL systematic review she implies was required. And why does someone who is adamant that conflicts of interest should be avoided produce a table of studies so heavily infected with Atkins Foundation funding?

If only Teicholz was intellectually honest enough to apply the standards to her own work which she demands of others.

Thats not to say she’s doesnt make some valid criticisms

The report provides no documentation of these “exploratory searches,” 

With hindsight this was a mistake.

They should have listed the papers found since 2000 on low carbohydrate diets and health in questions 1, 3, 4, 5, 6, 7 and perhaps those on body weight (question 2) since the previous guidelines.

By not doing so, they have allowed Teicholz and the BMJ to create an impression that the guidelines are ad hoc and not based in science and confuse the public further.

Mission accomplished for the headline grabbers and book sellers.


References

1  The Scientific report guiding the US dietary guidelines: is it scientific? BMJ 2015;351:h4962 http://www.bmj.com/content/351/bmj.h4962

Dietary Guidelines Advisory Committee. Scientific report part D: chapter 2. Dietary patterns, foods and nutrients, and health outcomes—continued. http://health.gov/dietaryguidelines/2015-scientific-report/07-chapter-2/d2-2.asp.

3  Dietary Guidelines Advisory Committee. Scientific report part D: chapter 2. Dietary patterns, foods and nutrients, and health outcomes — introduction. http://health.gov/dietaryguidelines/2015-scientific-report/07-chapter-2/

4  The Scientific report guiding the US dietary guidelines: is it scientific? BMJ 2015;351:h4962 http://www.bmj.com/content/bmj/suppl/2015/09/23/bmj.h4962.DC1/teicholzmaster2609.wt3_default.pdf

5 Improvement of gastroesophageal reflux disease after initiation of a low-carbohydrate diet: five brief case reports (PMID:11712463) http://europepmc.org/abstract/med/11712463

Eat Like an Ancient Egyptian

Nina Teicholz  is again busy rewriting history to make it fit better with her hypothesis that a diet heavy in meat is the best for health:

Lets deal first with the premise that these two images are representations of how we used to eat. The models in question are funerary objects which were found in the tomb of an Egyptian noble called Meketre1, who was a chancellor and chief steward during the reign of Mentuhotepo II and III during the Middle Kingdom (between about 2000 BC and 1700 BC).

What is funny here is that Teicholz blatantly omits other parts of the find from the very same tomb, which are housed in the very same Museum, which run counter to her thesis. For example the tomb also contained a model of a bakery and brewery 3 :

DT208237There is also a model of a granary 4 which according to the Museum description includes an “…accounting area…[…]…Keeping track of grain supplies was crucial…”:

DT2518 (2)

This should come as no surprise, since the Egyptians were an agricultural society who pretty much invented , and their success was attributable to large scale agriculture and irrigation techniques which they used to exploit the nutrient rich flood areas surrounding the Nile to grow crops.

It also seems that Teicholz fails to understand the purpose and context of these objects. These are not necessarily a record of what everyday people were eating at the time, they were specifically placed in the tombs of the elite – nobles and priests – along with actual food to sustain them in the afterlife, in the way in which they had become accustomed to during life.

Rather than showing how we used to eat, the “we” being the general population, these objects (including those awfully inconvenient depictions of grains) should more accurately be labelled: how the Ancient Egyptian elite ate.

Finally, lets looks consider the idea that when it comes to diet we forget history at our peril. While this appears to be a simple fallacious appeal to tradition (there is little reason to conclude this way of eating was the best for health back then, or that it is now) I’m going to agree with Teicholz on this one.

With this in mind, I look forward to hearing her thoughts on research 5 which shows that the mummified remains of Ancient Egyptian Priests (who ate the fairly well documented food offerings which were made to the gods – a meat heavy 50%+ fat diet high in saturated fat) showed the signs of what looks suspiciously like vascular calcification.


References

1 http://en.wikipedia.org/wiki/TT280

2 http://en.wikipedia.org/wiki/Middle_Kingdom_of_Egypt

3 http://www.metmuseum.org/collection/the-collection-online/search/544258

4 http://www.metmuseum.org/collection/the-collection-online/search/545281

5 http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(10)60294-2/fulltext

A letter to the BMJ: Lets talk about Hansen!

Over the past few weeks I have increasingly found myself – of my own volition I might add – whack-a-mole-in’ fallacious claims about the Swedish Government recommending a low carbohydrate diet.

I have traced the source of many of these claims as a particularly bad BMJ news article by Anders Hansen, so I thought it might be more productive to cut from the root and write to the BMJ calling for retraction, or substantial correction.

Now I know writing whiny complaint letters is more Clark Kent than Superman, but sometimes a few key points from a moaning pedant is a practical way of tackling the great menace of inaccuracy. So, lets see how we get on with this:

Dear BMJ

I am writing to express my concern regarding the news article “Swedish health advisory body says too much carbohydrate, not fat, leads to obesity”. 1

While I appreciate this is a now a historical news article from 2013, it contains numerous factual inaccuracies which continue – based on the reputation of the BMJ as a trusted source  – to be widely propagated and cited, wrongly, as conclusive evidence that low fat diets are ineffective for the treatment of obesity.

Indeed, despite the attempts of the chair of the HTA committee Nina Rehnquist to clarify matters in her rapid response to the article, it has now influenced a much wider audience, as it was cited in the best selling book ‘The Big Fat Surprise’ as the source of the following erroneous claim:

“…in 2013 in Sweden, an expert health advisory group, after spending two years reviewing 16,000 studies, concluded that a diet low in fat was an ineffective strategy for tackling either obesity or diabetes.”

Having read the english summary of the Health and Technology Assessment, I believe that the level of inaccuracy in this news piece combined with its now wide audience requires the BMJ to either retract the article, or substantially correct both the headline and content. Firstly, the title of the piece is inaccurate:

Swedish health advisory body says too much carbohydrate, not fat, leads to obesity

The Health and Technology Assessment cited did not consider the cause of obesity, only the treatment of obesity a point made clear by both the title of the report 2 and Nina Rehnquist’s rapid response.

As the article metrics show, the vast majority of readers have seen only the abstract of this article and I feel that this inaccurate title leaves the piece open to being mis-cited. With regards to the content of the article, there are a significant number of inaccuracies. The first line claims:

An influential Swedish health organisation has recommended a diet that is low in carbohydrates but not low in fat for people who are overweight or obese or have diabetes.

Unfortunately, the report did not consider the treatment of diabetes because this was the subject of an earlier separate Health and Technology Assessment in 2010.3 It is worth noting however that the earlier report on diabetes did not recommend a diet “low in carbohydrates but not low in fat”, in fact is states something quite different:

In type 2 diabetes, low-fat and moderate low-carbohydrate diets (30–40% of the energy from carbohydrates) have similar, favorable effects on HbA1c (long-term blood glucose) and bodyweight. The absence of sufficient-quality studies in people with diabetes prevents evaluation of the long-term effects of more extreme diets involving low-carbohydrate and high-fat intake, eg, so-called “low-carb, high-fat” (LCHF) diets. Hence, safety aspects become particularly important in clinical follow-up of individuals who choose extreme low-carbohydrate diets (10–20% energy from carbohydrates).

With regards to the claim that a diet “low in carbohydrates but not low in fat” was recommended for the treatment of obesity, this is correct only in the short term, and the report has more nuanced conclusions which suggest a range of equally effective options over the longer term:

Weight loss in adults. A range of advice on alteration of eating and drinking habits can result in obese individuals losing weight or reducing their waist size. In the short term (six months), advice on strict or moderate low carbohydrate diets is a more effective means of achieving weight loss than advice on low fat diets. In the long term, there are no differences in the effect on weight loss between advice on strict and moderate low carbohydrate diets, low fat diets, high protein diets, Mediterranean diets, diets aimed at achieving a low glycaemic load or diets containing a high percentage of monounsaturated fats. Advice on increasing the intake of dairy products (primarily milk) or reducing the intake of sweet drinks may also lead to weight loss.

Hanson further states:

The guideline advises that meat and fish rich in fat, along with nuts and olive oils, should form a large part of a healthy diet, while the consumption of pasta, potatoes, and white bread should be reduced.

No such recommendations are made within the report. In fact there were virtually no findings on individual foods, as the HTA report 2 clearly states:

However, all in all these studies provide no clear evidence for advice on individual foods for obese individuals in order to prevent morbidity or achieve weight loss.

In addition I can find no support in the HTA for the following claim made by Hansen:

The recommendation contradicts the generally held belief that people should avoid foods that are rich in fat, especially those high in saturated fat.

The HTA report 2 itself stating:

The studies relating to strict low carbohydrate diets which were included in the report give no indication of whether low carbohydrate diets should provide small portions or not include saturated fat…[…]…is not possible to draw any conclusions on the link between low carbohydrate diets – irrespective of fat content type – and cardiovascular morbidity. The precautionary principle could be applied here. This may result in restraint on the intake of saturated fat when advice is given on low carbohydrate diets, as long as the documentation on the long-term effects is so inadequate.

I would hope that you agree that there are serious inaccuracies in this article which continue to compromise the reputation of the BMJ. I would ask that you consider a formal retraction, or substantial correction of the article to address the above points.

Regards,

Slipp Digby

References

1 Swedish health advisory body says too much carbohydrate, not fat, leads to obesity. BMJ 2013;347:f6873

2 Swedish Council on Health Technology Assessment. Dietary Treatment of Obesity: A Systematic Review (No 218/2013), September 2013, ISBN: 978-91-85413-59-1.

3 Swedish Council on Health Technology Assessment. Dietary Treatment of Diabetes: A Systematic Review (No 201), August 2010, ISBN: 978-91-85413-37-9.

Update 30/5/2015

In response to my letter the BMJ have issued a very substantial correction which can be found here:

In this News story, “Swedish health advisory body says too much carbohydrate, not fat, leads to obesity” (BMJ2013;347:f6873, doi:10.1136/bmj.f6873), the headline and some of the text were incorrect. The report did not say that too much carbohydrate leads to obesity, as stated in the headline. It said that low carbohydrate diets were more beneficial for reducing obesity in the first six months of treatment, when compared with low fat diets, but made no difference at 12 months.

The report said that, in the longer term, “there are no differences in the effect on weight loss between advice on strict and moderate low carbohydrate diets, low fat diets, high protein diets, Mediterranean diets, diets aimed at achieving a low glycaemic load, or diets containing a high percentage of monounsaturated fats.” The report did not conclude that “the scientific evidence did not support a low fat diet.”

In addition, the report made few recommendations with regard to specific foods and did not say that “the consumption of pasta, potatoes, and white bread should be reduced.” We apologise for these errors.

Kudos to the BMJ for making a very full and formal retraction of these erroneous claims.

Finally an errata of my own! – In my original letter when referring to Nina Renquist’s rapid response I state “her” when it should in fact be “his” response. Apologies.

Nina Teicholz, Health Ministers and the Swedish “Government” Low-Carb Diet Guidelines

I’ve not yet got round to reading The Big Fat Surprise by investigative reporter Nina Teicholz, but her recent tweets in support of her thesis (the claim that the science says that a healthy diet includes large amount of fats from butter, meat and cheese) have become increasingly bizarre.

Here is an example:

Now, lets stop for a moment and think really hard about what she might be implying here.

Could it be that Teicholz knows in detail about the particular diets of these individuals (Maggie De Block, Belgium; Gabriel Wikström, Sweden and Gaetan Barrette, Quebec) and is implying that by observation alone we can see that one particular diet is the best for weight?

Even if that were true – and I can find no evidence to support the idea that Gabriel Wikström achieved or maintains his weight using LCHF – how does an uncontrolled observation based on three individuals with a multitude of other differences tell us anything about diet?

It also raises the ugly spectre of cherry picking – why were these particular members used as examples and not say the UK’s Jeremy Hunt, another country which hasn’t adopted low-carb dietary guidelines?

jeremy-hunt-wild-things

For the avoidance of confusion, Jeremy Hunt is the svelte chap on the left. No, the use of Health Ministers implies something else…….

Could it be then, that Teicholz is implying that you cannot be a health minister on merit, if your BMI isn’t acceptable?

Hmm, while there may be an element of offensive fat shaming involved, I think her further tweet eludes to her real meaning:

Teicholz seems to be implying that the health ministers are in some way the physical manifestation of the success of the dietary policies of the nations or province.

Aside from the fundamental daftness of this idea, and the fact that the Swedish Council on Health Technology Assessment was only written just over a year ago (thus having limited time to effect the health of an entire nation), she gets fundamental facts about it totally and utterly wrong.

It is not a Government Report or set of consumer guidelines, it is a Swedish Council on Health Technology Assessment.  This report has been misrepresented so much that Swedish National Food Agency even took the step of clarifying this matter:

Sweden does not have any guidelines on low-carb-high-fat diets. The information that Sweden has guidelines on low-carb-high-fat diets is based on incorrect information circulating on the Internet.

Has this investigative reporter heard of Google? Did she not think it weird that no-one has actually produced this set of paradigm shifting guidelines?

Also I cannot see how the report itself can be interpreted by Teicholz, or anyone to mean the Swedish Government is the first to:

…formally ditch the low-fat diet.”

I mean even with just the press release in English it seems pretty clear to me that the report states that Low Carb is the best for short term weight loss (<6 months), but is one of a number of comparable options for longer term weight loss which includes low fat and Mediterranean diets:-

In the short term (six months), advice on strict or moderate low carbohydrate diets is a more effective means of achieving weight loss than advice on low fat diets. In the long term, there are no differences in the effect on weight loss between advice on strict and moderate low carbohydrate diets, low fat diets, high protein diets, Mediterranean diets, diets aimed at achieving a low glycaemic load or diets containing a high percentage of monounsaturated fats.

Further the only diet for weight maintenance with sufficient evidence is low fat, in preference to either LC or Mediterranean:

Maintaining reduced weight. When obese individuals have lost weight, they can maintain their weight more effectively with advice on low fat diets with a low glycaemic index and/or high protein content rather than low fat diets with a high glycaemic index and/or low protein content. There is no data available to assess whether advice on low carbohydrate diets and Mediterranean diets, for example, is effective to prevent weight increase after weight loss.

For someone who is an investigative reporter there is a staggering amount of poor reasoning and a lack of fact checking here.

Its time for the zombie fact about the Swedish Low-Carb guidelines to be put back in its grave for good, and Nina can start that process with a retraction of what is clearly misinformation.

Updated 31/10/2014

In response to comments from Jacques Rousseau on twitter (do read his excellent blog post here) Nina Teicholz’s claims:

Firstly on the issue of policy, Health Technology assessments are authored by the independent Swedish SBU and the reports produced:

…could, for example, be an important source of information for other decision-making authorities, such as the National Board of Health and Welfare, the Medical Products Agency and the Dental and Pharmaceutical Benefits Agency. Professional associations of health care personnel, such as doctors, nurses and dentists, can use SBU reports as a basis in preparing their own guidelines. An SBU report can also be used at an individual health centre or clinic to provide guidance on the possible benefits for patients of introducing, prioritising or, in some cases, excluding methods.

Note the use of the words could, and can. The purpose of a HTA is to act as an independent guide to decision making. Yes the recommendations can be adopted within separate guidelines (or used to devolve decision making all the way down to individual doctors and nurses) but it is not and never will be a Government Policy. If Sweden had translated the HTA into guidelines rejecting the LF diet, where are they?

This are, of course moot points, because Nina Teicholz totally misrepresents the content of the report.

The idea that the authors were biased to keep in line with established wisdom is laughable – I mean just read the report itself, each decision was graded based upon specific evidence presented by the SBU and the evidence for LCHF was simply lacking, or absent in many area. If you don’t believe me feel free to read a translated summary here.

Faced with this refusal to amend her false claim I issued a simple challenge which would take no more than 10 minutes on google:

..and further offered to set the record straight if I am wrong:

After a number of requests Nina Teicholz simply blocked me on twitter.