In February, I wrote a blog post which aimed to draw attention to, in my view, the bias and lack of balance in an article on the NHS Choices website entitled ‘The Truth About Carbs’. I complained about this article, and had filled out the requisite form here. You’ll see that any complaint can be no more than 1500 characters. I had to aggressively prune back my original complaint to comply with the space allowed and, in the end, my complaint came in at less than 250 words. Hey ho.
Here’s the wording of the complaint I was able to submit:
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I’d like to complain about this article: http://www.nhs.uk/Livewell/loseweight/Pages/the-truth-about-carbs.aspx. The article tells us that that carbohydrates are a major source of energy. Even on a very low-carb diet, individuals are able to get energy fat and protein, and the absolute requirement for carbohydrate in the diet for energy is actually none at all (if we’re going to be accurate about it). Regarding weight control, there is no recognition in this article of the influence of hormones such as insulin and leptin on fat storage, and the differing effects of the major macronutrients here.
I believe that the idea that ‘fibre is filling’ is also misleading. In fact, there is evidence to show that when individuals adopt a low-carb diet, they very eat several hundred calories less each day quite spontaneously. The article cites one study as evidence of the fact that low-carb diets do not produce better weight loss in the long term, though attrition rates (and possibly adherence) was poor.
See here http://authoritynutrition.com/23-studies-on-low-carb-and-low-fat-diets/ for a comprehensive review of 23 studies which demonstrates superior results achieved by low-carb diets with regard to weight loss and disease markers. To my mind, dietician Sian Porter and the NHS Choices website have done a bad job of communicating the facts and summarising the evidence. I wish to formally complain about the inaccuracies in this article and its (to me) clear bias and lack of balance.
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I stated in the blog that I had not had a response to the piece after 2 months. I tweeted to this effect, and was assured by one of the editors of NHS Choices that I had been sent a reply. When I questioned this, it turned out no response had been sent. The confusion was put down to ‘Human error’.
Shortly after, I did get a response, which I posted as an addendum to the blog. I felt the response was inadequate. The Managing Director of NHS Choices (Jonathan Carr-Brown) agreed, and eventually got back to me with a more fulsome response on 25 February, which I have pasted below. I’ve also added my response to the points Mr Carr-Brown makes.
Response from NHS Choices
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Taking your points into account, we stand by our article “The Truth About Carbs” [http://www.nhs.uk/livewell/loseweight/pages/the-truth-about-carbs.aspx].
This article is part of a package of healthy living content on NHS Choices and abides by our standard editorial process [http://www.nhs.uk/aboutNHSChoices/aboutnhschoices/Aboutus/Pages/Editorialpolicy.aspx]. It provides a balanced and informed view to the general public, not any particular interest group (for example, it is not aimed at diabetics in general, although it does offer some information on carbs and diabetes). It is also not written to undermine any individual, any group, or any lifestyle choice – in fact it was written with the aim of helping people taking their own informed, healthy choices.
Turning to the specific points you raise – you are right – people can survive with little carbohydrate. However, this does not change the facts as we have presented them. This article is information about healthy diet for most ordinary people, it does not explore every possible avenue of diet.
This is also the case when it comes to hormones. We know they affect people, but there is little that we can credibly say to a general readership that will be of particular help when trying to maintain a healthy diet and/or achieve healthy, sustainable weight loss.
We have used the term “Fibre is filling”. Obviously, feelings of fullness are subjective, but the statement is subjectively true – in this sentence it is shorthand for “foods containing high levels of fibre tend to be more filling”. That is not to say that people who are eating a low-carb diet will not experience satiety.
Our “The Truth About Carbs” article is balanced – it provides links to studies that found that low-carb diets produced better weight loss than low-fat diets in the populations studied and in the particular circumstances of those studies. It is not the case that the article cites one study as evidence of the fact that low-carb diets do not produce better weight gain. If you read it as a whole, you will see that it has approached the research fairly.
In fact, it presents three systematic reviews of other studies that suggest that low-carb diets may produce better results than low-fat diets. It then cites a single systematic review suggesting that low-carb diets may not be demonstrated to have more effect than low-fat at 12 months, and another systematic review suggesting that low-carb diets were no more effective in the long term.
And we go on to say, “The weakness of current research is that most studies are short term and of varying quality and there is a recognised need for longer-term, rigorous evaluation. Moreover – and this applies to most research on diets – it is notoriously difficult to study the effects of diet on health because people don’t live in labs, they live in the real world and are exposed to different lifestyle and environmental factors, which can influence the results.”
The AuthorityNutrition.com article cited does indeed link to 23 peer-reviewed studies, but as with the NHS Choices article, it is not a systematic review. On examination of the studies presented these appear to have been picked for their favourability towards results for low-carbohydrate diets, and there does not seem a balancing view. For this reason, we view it with caution.
Having looked briefly at the studies themselves – these largely appear to be short-duration, small or modestly sized randomised trials. Many of them look only at specific populations (eg. diabetics, adolescents, postmenopausal women), and for a considerable number of them, the weight loss effects of the diet (while reported) are not the primary outcome of the research. Some of them find a difference, but not a statistically significant one.
We also view it with caution because the “Weight loss” graph presented in the article portrays the average weight loss of the patients combined without taking into account sample size, study participant characteristics (eg. initial weight). This has the effect of distorting the apparent significance of these studies, and has not been done with the kind of comparative rigour as you would find in a standard box-diagram commonly used in meta-analyses.
These points are the kinds of issues that we consider when we critically appraise the evidence. As such, AuthorityNutrition.com’s article does not constitute evidence, but a cherry-picking of science to prove a particular point.
It is important to view this article as one of thousands on the NHS Choices website. It is aimed at a broad audience, not just those who wish to, or are trying, one particular diet. This is demonstrated by the fact that the article was visited more than 15,000 times in January alone and nearly 30,000 times since its publication in November 2013.
If you have any further, specific points that you would like to raise about this article, please get in touch with us again. Having said that, in reviewing the content again and although you didn’t raise it, we have changed a part of the article that described ketones as “toxic chemicals”, which was factually incorrect. The rest of the article was factually correct.
We are proud of our content, and if this has given you a chance to reconsider your view, you may be interested in syndicating NHS Choices content onto your own personal site. For information about syndication, visit http://www.nhs.uk/aboutNHSChoices/professionals/syndication/Pages/Webservices.aspx
If you wish to continue to formally complain about NHS Choices’ content, please read about our complaints process here: http://www.nhs.uk/aboutNHSChoices/aboutnhschoices/Aboutus/Documents/120117-nhs-choices-complaints-policy-v2-D01.pdf
Regards
Jonathon Carr-Brown
Managing Director
NHS Choices
Health and Social Care Information Centre
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My Response to NHS Choices
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Dear Jonathan
Thank you for your email of 28th February. You kindly invited me to get back in touch with any further issues I had regarding the article The Truth About Carbs. I would like to take this opportunity now.
The response states that the article provides a balanced and informed view, and was not written to undermine any individual, any group, or any lifestyle choice. We’ll get to the issue of balance and the relevant evidence later on. Whether there was an intention or not to undermine anyone or anything, readers can be left in little doubt that the piece came down strongly in favour of carbohydrate-rich diets and against lower-carbohydrate regimes. Whatever the intent, I think the end result is clear.
The response that the article “was written with the aim of helping people taking their own informed, healthy choices.” Whether or not the article did this is a moot point (see below). My impression is that the article was less about people taking their own informed choices, and more about telling people what to eat (i.e. a carb-rich diet).
In the article, the essential nature of carbohydrate is alluded to more than once. For example “Carbohydrates are one of three macronutrients (nutrients required in large amounts)”, “Why do we need carbs?” and “Carbs are important to your health for a number of reasons.”
But, as I pointed out in my original complaint, the dietary requirement for carbohydrate is zero. The response states that the article is factually correct (other than your prior assertion that ketones are ‘toxic’). However, it is not factually correct to assert that carbohydrate is needed by the body.
The response appears to acknowledge the effect of hormones on weight and health, but says “there’s little that they can credibly say to a general readership that will be of particular help”. I find this patronising. My experience is that the general public is generally very capable of understanding biochemical and physiological information and its relevance to health and wellness.
The response states: “We have used the term “Fibre is filling”. Obviously, feelings of fullness are subjective, but the statement is subjectively true – in this sentence it is shorthand for “foods containing high levels of fibre tend to be more filling”.
This may be “subjectively true”, but I’d say that we should be relying more on objective evidence, where it exists. And it does. In this 2013 review of 44 studies assessing the effect of increased fibre on appetite and food intake [Clark MJ, et al. The effect of fiber on satiety and food intake: a systematic review. J Am Coll Nutr. 2013;32(3):200-11] concluded:
• Most acute fiber treatments (61%) did not enhance satiety.
• Most acute fiber treatments (78%) did not reduce food intake.
• Neither fiber type nor fiber dose were related to satiety response or food intake.
I suggest the subjective observation that ‘fibre is filling’ is not evidence-based and that the article should reflect this.
The article concedes that “That is not to say that people who are eating a low-carb diet will not experience satiety.” In fact, there is good evidence that lower–carb diets lead to a spontaneous reduction in calorie intake, and that the more fat is eaten, generally the less is eaten quite naturally [Johnstone AM, et al. Effects of a high-protein ketogenic diet on hunger, appetite, and weight loss in obese men feeding ad libitum. AJCN 2008;87:44-55].
The ability of lower-carb diets to lead to a spontaneous reduction in food intake received scant attention in the article, in stark contrast to the (inaccurate and misleading) information on fibre. This suggests, to me, bias in the article.
The response states, “it provides links to studies that found that low-carb diets produced better weight loss than low-fat diets in the populations studied and in the particular circumstances of those studies. It is not the case that the article cites one study as evidence of the fact that low-carb diets do not produce better weight gain. If you read it as a whole, you will see that it has approached the research fairly.”
I’ve copied the relevant part of the article below. Then I’m going to list the studies (I’ve added reference numbers for ease), and comment on them.
• A 2013 review of 13 studies involving 1,569 participants concluded that those assigned to a very-low-carbohydrate ketogenic diet (VLCKD) achieved greater long-term (at least a year) reductions in body weight and certain cardiovascular risk factors than those assigned to a low-fat diet [1]. The authors concluded that a VLCKD “may be an alternative tool against obesity”.
• Another review from 2013 of 17 studies involving 1,141 obese patients suggested that low-carb diets “had favourable effects on body weight and major cardiovascular risk factors”, although the effects on long-term health were unknown [2].
• A 2009 study comparing low-carb diets with low-fat diets examined 13 studies involving 1,222 participants, concluded that low-carb diets were “more effective at six months” and were “as effective, if not more” as low-fat diets at 12 months [3].Other research suggests that over periods of 12 months and beyond, low-carb diets fare no better than low-fat diets and there is some concern about the long-term health impact. There is strong and consistent evidence that reducing your calorie-intake is more important for losing weight than changing the proportion of carbs, fat and protein in your diet:
• A 2013 report [4] on the safety of low-carb diets reviewed 17 studies involving more than 272,000 people and found low-carb diets were “associated with a significantly higher risk” of death and no reduction in the risk of cardiovascular disease.
• A 2006 review comparing low-carb diets with low-fat diets examined five studies involving 447 individuals found that those on a low-carb diet had lost more weight than those on a low-fat diet at six months but not at 12 months [5].
• A 2004 review of the long-term benefits of various weight loss methods analysed 26 studies and found no evidence that low-carb diets resulted in greater weight loss than low-fat diets over the long term [6].
1. Bueno NB, et al. Very-low-carbohydrate ketogenic diet v. low-fat diet for long-term weight loss: a meta-analysis of randomised controlled trials. Br J Nutr. 2013;110(7):1178-87.
2. Santos FL, et al. Systematic review and meta-analysis of clinical trials of the effects of low carbohydrate diets on cardiovascular risk factors. Obes Rev. 2012 Nov;13(11):1048-66
3. Hession M, et al. Systematic review of randomized controlled trials of low-carbohydrate vs. low-fat/low-calorie diets in the management of obesity and its comorbidities. Obes Rev. 2009 Jan;10(1):36-50
As is alluded in the article, all of these reviews provide evidence that low-carb diets produce better weight loss and disease marker changes than low-fat diets.
4. Noto H, et al. Low-carbohydrate diets and all-cause mortality: a systematic review and meta-analysis of observational studies. PLoS One. 2013;8(1):e55030.
As the title of this review states, this is based on ‘observational’ (or epidemiological) studies. These studies may indeed have found a link between lower-carbohydrate intakes and increased risk of death, but this does not mean that low-carb diets cause death. It is possible, for instance, that those in the poorest health tended to adopt lower-carb diets in order to improve their health. In fact, the authors of the review state this: “the relation may not necessarily be causal, particularly in the observational studies because of possible confounding factors and biases that may not have been fully adjusted for, which may have rendered the results less valid.”
Another major issue with these sorts of studies is that they are usually based on self-reporting of the diet which is notoriously prone to error.
While intervention studies may have issues too, it is generally accepted in scientific circles that they are superior to epidemiological studies.
5. Nordmann AJ, et al. Effects of low-carbohydrate vs low-fat diets on weight loss and cardiovascular risk factors: a meta-analysis of randomized controlled trials. Arch Intern Med. 2006;166(3):285-93.
Here’s what the authors concludes as regard to the effect on weight loss: “Low-carbohydrate, non-energy-restricted diets appear to be at least as effective as low-fat, energy-restricted diets in inducing weight loss for up to 1 year.”
Again, the balance of evidence favoured low-carb over low-fat, and yet this study is listed in a part of article that purports to provide evidence that low-carb diets have no particular merit.
6. Avenell A, et al. What are the long-term benefits of weight reducing diets in adults? A systematic review of randomized controlled trials. J Hum Nutr Diet. 2004;17(4):317-35.
The article states that this review ‘found no evidence that low-carb diets resulted in greater weight loss than low-fat diets over the long term’.
Actually, none of the studies in this review compared low-carbohydrate diets to low-fat diets, explicitly. No explicit claim is made by the authors to this effect either.
The review did assess the impact of ‘low-carbohydrate protein sparing modified fast’ diets. But these are generally very low calorie diets (often on 300-500 calories a day) that are consumed in the short term. These diets in no way represent ‘low carbohydrate diets’ that are usually ‘ad libitum’ (unlimited quantities of prescribed foods are permitted). The Avenell review is simply not relevant to the debate here.
So, to summarise, the evidence cited by the article is comprised of:
1. Four reviews [1,2,3,5] of intervention studies that are broadly supportive of low-carbohydrate eating as superior to low-fat dieting.
2. One epidemiological review which links low-carbohydrate eating with increased risk of death which is based on unreliable dietary data and from which no causality can be inferred.
3. One review [6] which is misrepresented in the article and is not relevant to the discussion.
Despite the fact that the evidence cited is overwhelmingly in favour of low-carbohydrate diets, the tone of the article is clearly disapproving of this way of eating. I suggest that the article does not reflect the balance of evidence at all.
The review of the literature in the article is followed by the following paragraph, which is also reproduced in your response response:
“The weakness of current research is that most studies are short term and of varying quality and there is a recognised need for longer-term, rigorous evaluation. Moreover – and this applies to most research on diets – it is notoriously difficult to study the effects of diet on health because people don’t live in labs, they live in the real world and are exposed to different lifestyle and environmental factors, which can influence the results.”
I don’t dispute this, but if “there is a recognised need for longer-term, rigorous evaluation”, then how can NHS Choices and its dietician confidently tell us that a third of our diet should come from starchy foods? The advice is strong and certain, and I’d like an opportunity to assess the quality of the evidence on which this advice is based. I do hope that you will respond with the specific research that supports this position.
As regards the piece that I linked to at Authority Nutrition, I accept this was not a systematic review in the conventional sense. I also accept some of the shortcomings of the research. However, all of the studies cited provide evidence that, overall, lower-carb diets are superior to low-fat ones.
Rather than criticising the article and accuse it of ‘cherry-picking’, maybe you could respond with a list of studies that support the dietary approach you advocate. I note that none of the reviews of clinical evidence cited in the article support the dietary approach it advocates.
I am glad you have seen fit to remove the word ‘toxic’ in relation to ketones. I note, though, that the relevant part of the article now reads:
“When you are low on glucose, the body breaks down stored fat to convert it into energy. This process causes a build up of ketones in the blood, resulting in ketosis. Ketosis as a result of a low carbohydrate diet can be accompanied by headaches, weakness, nausea, dehydration, dizziness and irritability particularly in the short term.”
So, while you concede that ketones are not toxic, the remaining paragraph gives the distinct impression that they can have toxic effects in the body.
For the reasons explained above, I believe the article remains misleading and not evidence-based. I disagree that the article is balanced (and something to be proud of). I would be very grateful if you could respond point-by-point to the issues I raise here.
John Briffa
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I got an almost immediate response from Mr Carr-Brown, who suggested we discuss the issues when we meet. I said I’d like a formal response, and that the complaint should be escalated to what is known as the ‘Clinical Information Advisory Group’. We shall see what comes of this in due course.
In the meantime, as for the suggestion that I syndicate NHS Choices content on my own site, I think I’ll pass: Disseminating unscientific, non-evidence-based, misleading and potentially dangerous dietary advice is not a business I want to be in.
