Ex-Lawyer and Author David Gillespie is no stranger to the program. He's been on talking about his book "Sweet Poison: Why Sugar Makes Us Fat". Today, he came back in to chat to Steve about his latest book: "Toxic Oil - Why Vegetable Oil Will Kill You, and How to Save Yourself"...
Firstly I would like to congratulate you on a job well done with this interview, you asked all of the right questions in my opinion. It is only your lack of knowledge of the science which allowed David Gillespie to misrepresent the research and get away with numerous mistakes (which you can't be blamed for, it is a complex topic and one which requires specialised knowledge to follow and access to information that isn't freely available). Under the circumstances (only having David Gillespie in studio), you obviously had to take his word on what he claimed - I can only hope that as a journalist, that you now do some fact checking to confirm the accuracy of some of those statements. I would like to offer some help in this department and have much more information than listed here to offer, if you are interested.
The first red flag in David's entire 'research' process is the definition of science that he uses in Toxic Oil. He states that "Science is based on people making hypotheses about how things might work and then collecting evidence that will prove them right (or wrong)". This ISN'T how science works, in fact to me, it sounds more like how the law works.
In science, a person would normally read the literature and then come to a conclusion or form a hypothesis on that basis. They would actually test their hypothesis and then compare it to existing data, not simply collect the stuff they liked! Cherry picking isn't science! A lawyer is usually given their conclusion first (which 'side' they are on) and then collect evidence to support that position. Scientists commonly refer to papers which disagree with their own work in a study - usually found in the 'discussion' section of a paper. There, the results of a study are normally put into context with other data, pointing other the weaknesses and strengths of all relating studies to see how that paper adds to the body of evidence. In contrast, I'm sure anyone would be shocked to hear a lawyer get up in court and discuss any weaknesses of their case, where the opposition had a stronger case and where their own needed improving. In fact, I would predict that the lawyer wouldn't mention the weaknesses of their case and certainly not mention evidence against (unless it was to discredit or argue against it). As a friend stated (somewhat facetiously) when discussing this exact topic "Lawyers are trained to make a case, not find the truth!”
This is exactly the manner in which David Gillespie writes his books and discusses data in interviews. From David, you hear about the research that (allegedly) supports his case. Often only the evidence against his theories are referred to when David attempts to debunk it (sometimes merely with an ad hominem attack of sponsorship and vested interests). You certainly aren't made aware of how much evidence appears to contradict David's theories. In fact it is often the opposite - you are led to think that the evidence can only lead a reasonable person to the same conclusions. A small amount of research will show exactly how much evidence David leaves out of his discussions - data that would at best, suggest caution but hardly agree with his black and white, true or false, 100% confident views of many aspects of health and nutrition. A perfect example of this is David's position on exercise and weight loss. Not only does David reference less than a dozen papers (and misquotes many, cherry picking certain pieces of evidence) in Big Fat Lies but he ignores the vast bulk of the research (thousands of studies). Here is a more detailed discussion of where David falls down in the 'exercise debate' http://davidgillespiesbigfatlies.com/32/science-does-support-using-exercise-for-weight-loss/ and http://davidgillespiesbigfatlies.com/75/big-fat-lies-on-exercise-and-weight-loss/
Similarly in Toxic Oil, David picks out bits of information that make his case, often misrepresenting the authors actual findings in order to make that case. Let's start with the LA Veterans trial (A Controlled Clinical Trial of a Diet High in Unsaturated Fat in Preventing Complications of Atherosclerosis
http://circ.ahajournals.org/content/40/1S2/II-1.abstract) - where David claimed there were more cancer deaths (which is correct). The original paper lists 7 vs. 2 in the experimental vs. the control groups, but a follow-up reanalysis (http://www.thelancet.com/journals/lancet/article/PIIS0140673671910865/abstract) gives the figures at 31 vs. 17. The most relevant point is that in both cases, the figures weren't statistically significant. In the original paper, the important quote David Gillespie conveniently doesn't mention is that "Consideration of causes of death in this category suggested that this difference probably did not reflect a toxic effect of the experimental diet." The re-analysis states that "Our results and those from the literature are uncertain and confusing in respect of the role of polyunsaturated fats in an increased incidence of malignancies. The high incidence of fatal carcinomas in our experimental group is of borderline significance. A retrospective review of any large collection of data will suggest causal relationships which are chance occurrences." The authors also make an interesting observation regarding the fact that a considerable number of those with cancer in the experimental group (10 of the 31) were placed in the 0-10% group for adherence to the experimental diet. On this the authors stated "Many of the cancer deaths in the experimental group were among those who did not adhere closely to the diet. This reduces the possibility that the feeding of polyunsaturated oils was responsible for the excess carcinoma mortality observed in the experimental group. A high incidence among high adherers would be expected if some constituent of the experimental diet were contributing to cancer fatality." These statements, especially those in the reanalysis, directly contradict David Gillespie's representation of the study! But David cites this as evidence for his hypothesis and most people are none the wiser!
It is curious that David Gillespie finds the Veterans Trial compelling evidence. Why does he ignore the statistically significant improvement the polyunsaturated group regarding atherosclerotic events (i.e. less chance of another cardiovascular event) but highlights the changes in cancer incidence which weren't statistically significant? Surely if it is a quality study, all of the findings are relevant?
The reanalysis of the Sydney Heart Study as published in the British Medical Journal was titled "Use of dietary linoleic acid for secondary prevention of coronary heart disease and death: evaluation of recovered data from the Sydney Diet Heart Study and updated meta-analysis" (which David referred to as double-blind, is wasn't!). This reanalysis also has some questions over it, especially with regards to sample size, statistical analysis, accurate analysis of the trans-fats effect, target population and how well these results can be extrapolated to the general population. Many of these issues are summarised by experts comments found on this page http://www.smc.org.au/2013/02/round-up-dietary-fats-and-heart-disease-bmj-experts-respond/. It will be interesting to see how the authors respond to letters sent to the journal in the coming weeks and months (some responses can be seen here http://www.bmj.com/content/346/bmj.e8707?tab=responses).
Not only does David Gillespie misrepresent the data, he seems to enjoy taking his message to the most extreme (and illogical) interpretation. Statements such as fructose is poison and every mouthful of vegetable oils takes your one step closer to a deadly and irreversible outcome aren't supported by ANY evidence to my knowledge! David's claims that Australians don't eat animal fats any more, or that type II diabetes "is a disease which is entirely put down to over-consumption of sugar" also are pure conjecture and contradict a large amount of evidence, not to mention common sense. If David Gillespie did represent the research properly, he should admit that NONE of it is strong enough to draw these extreme conclusions! There is no justification for these polarising and irresponsible claims! Studies using 15% Omega six oils or 25% fructose as a percentage of total calories DO NOT prove David's positions that these products should be eliminated! 'The dose makes the poison' has been known since the Renaissance! Even the group from the BMJ article with the questionable re-analysis of the Sydney Heart Study data state that their conclusions "caution should be used when extrapolating results to other populations".
So we must ask on what basis David Gillespie states that every mouthful is causing irreversible damage?
I enjoyed your question asking has there been any other studies to counter David's references. David incorrectly stated that there have only been three human (double blind) trials, and as noted above - they did not all arrive at the same result! The Veterans Trial didn't arrive confirm David's hypothesis, the Corn Oil trial did and it is debatable whether the Sydney Heart Study trial did. The original study didn't and stated that "Multivariate analysis showed that none of the dietary factors were significantly related to survival". The most recent analysis wasn't available when David would have been writing the book, so can hardly be used as evidence for him reaching his 'evidence-based' conclusion. There actually are a number of other studies - two of which are listed in the discussion paper of the Veteran's Trial re-analysis (so I can't see how he missed them!). When the authors discussed the possibility that the Omega-6 oils could be related to cancer they state "The experience of other investigators using similar diets has not been the same. In an eleven-year report on the Oslo diet-heart study Leren noted 7 cancer deaths in his experimental group and 5 in the control group. (4) His criteria for a diagnosis of cancer are not given, and diets were not supervised after the fifth year. The six-year London trial of a diet high in soya-bean oil noted 6 cancer deaths in the control group and 1 in the experimental group". So if you looking for other data start with the Oslo and London trials (not to mention Helsinki, Minnesota and the meta-analysis of all entitled "CANCER AMONG MEN ON CHOLESTEROL-LOWERING DIETS - Experience from Five Clinical Trials - http://www.thelancet.com/journals/lancet/article/PIIS0140-6736%2871%2990911-1/abstract).
I would further question David Gillespie’s ability to even understand and interpret research after the recent statements outlined here http://davidgillespiesbigfatlies.com/264/can-david-gillespie-actually-read-and-understand-a-science-paper/ or at the very least, his ability to accurately report it.
Now, on to David's 'test' of leaving a tub of margarine on a bench top to see how bad it is and easily oxidised. If this is the mechanism for why seed oils are so bad, I must ask what happens to olive oil when left out (mono-unsaturates which David highly recommended) let alone Omega-3 fats (with are also poly-unsaturates) like fish oils? Data suggests both can have positive effects on cardiovascular disease - but one would assume they should be causing a lot of cancer too? Based on David Gillespie's oversimplified 'mechanism' - they would all be bad!
I am still baffled by David's claims that current diets are almost exclusively seed oils and animal fats have also disappeared? I'd like to see the data for that (and bet the meat and dairy industry are upset if they still exist!). National survey data certainly doesn't show that!
Finally I can't disagree with the message of shopping on the perimeter of the supermarket and trying to eat more whole foods - it is the advice been given for decades!
Happy to help out if you need any further assistance in this area - I'm hoping that you will be following the ABC guidelines (as your Sydney colleague has, much to the chagrin of David Gillespie) in giving a balanced view on these topics.
Posted by: David M Driscoll |
01 March 2013 at 09:31 AM