Re: High-fat Low-carb Diets Could Mean Significant Heart Ris
I don't want to start an acrimonius discussion but I do think that some of the statements made earlier shouldn't pass unchallenged . I've left a comment about this study in particular to the end as I think some of the principles are more important
1) I don't believe it is a valid assumption to think that a funding source alters the
data., though I accept that negative results are not always published or published in obscure journals. Funding is normally accepted by universities with the caveat that the funding source has no input into the course of the study. It is inevitable that companies are going to fund areas of research that
may produce results that support their products.*.(Atkins foundation ring a bell ?) That is why sponsors and other interests are disclosed very clearly. Academics have lost university posts and had papers withdrawn when interests hav been found not to be transparent.
Any critique should be based upon methodology. Otherwise it is tantamount to accusing the researchers of professional malpractice ie: explicit fraud. This is libelous.
Of course on occasion it is thought that fraud has taken place, think Cyril Burt, Andrew Wakefield. It destroys a career or reputation when discovered.
One safeguard is that protocols for the study are produced, registered and often published in advance of the final paper. Trials are also evaluated by ethics commitees.
(see
http://www.controlled-trials.com/ISRCTN85769730) for this particular one.
The paper when published is subject to peer review, this prior documentation is part of the review process. In this case the Journal was Diabetes, a reputable journal.
Some papers are published in journals that the researchers themselves are on the editorial board , I personally find this a potential problem .
2) Any research adds to the body of literature. It may support existing literature (as the authors of this paper claim.) It may become even become a part of scientific 'knowledge' if other researchers produce findings that support it . On the other hand it may be falsified. This is how the scientific method works. As yet this study has only one citation and that is part of a review. It is a little soon for any studies to be published using the findings as an hypothesis.
3) The inability of other researchers to validate Yudkins hypothesis on sugar and heart disease was a reason that he lost influence in the UK.
Yudkin was taken seriously and he had a lot of support,both in the popular press and from some cardiologists. Research by scientists here and elsewhere however didn't appear to support his views.
His views were considered important enough that a working party of the Medical research council was set up to investigate the relationship between sugar and vascular disease. Amongst other studies they commisioned one by Burns Cox and Richard Doll . This 'exactly' replicated Yudkin's which linked heart disease with a very much higher intake of sugar. It didn't produce the same results .
http://www.ncbi.nlm.nih.gov/pmc/article ... 5-0079.pdf
After evaluating the evidence, the working party concluded ' the evidence in favour of a high sugar intake as a major factor in the development of myocardial infarction is extremely slender.'
http://qjmed.oxfordjournals.org/content/102/2/81.full
4) The energy intake varying in the 2 arms of this study is a result of randomisation. (it actually would be stranger if they were the same) The low carb had a slightly greater energy intake than the low fat arm. However the purpose of the study was to investigate the effects on various markers after specific diets. It was not a trial to find which arm produced the largest loss.
Diet was individualised (retaining the same proportions) to produce a weight loss of 0.5kg a week. Those randomised to the low carb arm were slightly heavier, thus were able to take in more calories whilst losing the required amount of weight ...if they had eaten exactly the same amount of calories their weight loss would have been higher.
The low carb arm received 20% of energy from carbs, this amounted to an average of about 95g. The amount of carbs in the example day described adds up to this level. (hash brown would be about 12.4g, bread 28.2g, potatoes 30g , peas 7g, carrots 4g =81.6g carb, the remaining carbs would come from the breadcrumbs, gravy granules etc )
