On Cherry Picking & Debunking
A repeated response - in the comments here and over at Weighty Matters - to my recent post, Calories, fat or carbohydrates? Why diets work (when they do) , included two criticisms.
- That I am guilty of the same cherry picking that I accuse Taubes of, and
- That my conclusions are somehow misguided, or whatever, because they are not what the original authors concluded or were studying.
OK. So to the first point, what is cherry picking? Well, there are two types:
a. Including only references that support one's theories and ignoring those that refute it, or
b. Selecting phrases or data from a single source while ignoring other phrases or data that contradict one's thesis.
I hereby award Taubes an honorary PhD (as in piled higher and deeper) in Cherry Picking from the distance learning institute at the Asylum. He has demonstrated an extraordinary aptitude in cherry picking of all varieties. If the triple thesis half decade of work culminating in GCBC weren't enough, he solidified his worthiness for this degree with the thesis he published in the peer review journal of the ISLCF*.
Example of (a) here: Insulin Resistance ~ Taubes v. McGarry While that post focused on Taubes misrepresenting McGarry's work, one can see how rather than pursuing McGarry's work, he chose to highlight the older suppositions of Neel. Taubes' references in GCBC are copious, but his research and referencing in the text are FAR from comprehensive or exhaustive. There's a difference.
But the examples of (b) are far easier to cite and list where Dr. Taubes is concerned. Firstly we have the Shai study. A more clear demonstration of cherry picking would be difficult to find. He ignores one third of the data in the study! If that data were consistent with his thesis, this might be acceptable. Pitting LC vs. LF is a pretty fair head-to-head given the low fat craze. But the MDTN group data was inconsistent with his thesis. They restricted carbs the least and lost more weight than the LF group and ever so slightly (statistically the same) less weight than the LC group. You can't get around the blatancy of this!
Some more examples of (b):
GCBC Reference Check ~ Part I of ? ~ Metabolic Adaptability & Energy Balance
In this one, Taubes cites a the "dieting is difficult" quote from a text he now admits he never read. But at the time one might assume he at least read the chapter of the text from which he *picked* this quote. Agree or not with Frayn's analysis in this chapter, it does not support Taubes' theories.
Then there's Taubes failure to include contradictory evidence from elsewhere in Frayn's book as regards Insulin Resistance and de novo lipogenesis to name a few. I would add that Taubes' discussion of IR is fraught with examples of (a) as regards his utter failure to pursue the works of one of his cited scientists.GCBC Reference Check ~ Part III of ? ~ Is glycerol phosphate rate-limiting?
This one is the most egregious of all. Not only did he cherry pick, but he referenced the entire discussion and flat out misrepresents what the text said. Can't get much worse than this one.
Lastly, although this list could go on and on and on, we have GCBC Reference Check ~ Part IV of ? ~ Kipnis. This is perhaps the most pertinent example of all, because Grey & Kipnis was the study I discussed in the Calories, fat or carbohydrates? Why diets work (when they do) post. At the time I was not aware that Taubes was familiar with this work. But he was, and then some! He also interviewed Kipnis. At least he presented Kipnis' views forthrightly but he did not do much of the sort of "deep thinking" I'm accused of avoiding as regards this GCBC reference.
So basically I'm accused of cherry picking from this same study because:
a. I didn't address that high or low carb did alter fasting insulin levels, and
b. I drew a different conclusion from the data than did the authors. Their's being: "composition of the diet [carb content] may represent a significant causative factor for the elevated plasma insulin levels observed characteristically in marked obesity", and "Thus the hyperinsulinemia characteristic of obesity may be the result of dietary factors rather than exclusively a consequence of the insulin antagonism associated with obesity"
Let's address these one at a time. In Calories, fat or carbohydrates? Why diets work (when they do), I was looking at the evidence in support of the assertion that it is calories that determine weight loss irrespective carbohydrate intake. In that regard I focused solely on calorie and carb consumption and the resulting changes, if any, in body weight in G&K. This, folks, is not cherry picking. Cherry picking would have been failure to include some data in this study demonstrating otherwise. But I discussed ALL of the results pertinent to just this topic. Similarly with Shai, I discuss all of the data and offer a reasonable (almost assured) explanation for all of them: e.g. that self report dietary records are to be taken with a grain of salt. (Which coincidentally I'm in agreement with Taubes on.)
On to point 2. What of the dust-up over drawing different conclusions than the authors? First, I would state that I'm not the only one who has ever looked at the data from studies to look at different variables. I mean do the names Denise Minger or Ned Kock not ring a bell for most of my readers? Aren't bloggers routinely having a field day "debunking" scientific studies by concluding just the opposite of those willful failure, Big ______ (fill in the blank) funded, American post-WWII era, lacking the sense of a well educated child, researchers all the time? (Some successfully, some not so much.) Forgetting the blogosphere, peer review journals are filled with "letters to the editors" and responses to published studies challenging the conclusions of the primary researchers.
So if you want to challenge my conclusions from G&K, do so on the basis of whether or not the data support them or not, and not that G&K were looking at other things. In this regard:
- G&K demonstrated absolutely no correlation between fasting insulin and weight change. Therefore fasting insulin is not a factor in determining weight loss.
- G&K demonstrated that controlling for calories and varying carbohydrate content of the diet resulted in weight maintenance or similar weight losses. Calories at ad lib levels maintained weight and calorie reduction resulted in weight loss irrespective of carb/fat composition of the diets. Therefore, calorie deficit, not carbohydrate content is the reason diets work when they do.
I have a post in the hopper addressing what G&K were looking at. But I'm under no obligation to address that -- it's not a focus of mine because I do not subscribe to the insulin-centric theories on obesity. However I would like to address why I think carbohydrate content of the diet can contribute to chronic hyperinsulinemia in the ALREADY OBESE & possibly IR.
Still, I invite any and all of my cherry picker accusers to present me with a study, or data, that supports the insulin hypothesis. I'm happy to discuss them in detail. You won't get a "oh that's just in rats" or other such dismissive, and failure to address the data on merit from me. For that kind of interesting exercise in deep thought you can go to the professionals. ;-)
* International Society of Low Carb Fanatics
Apparently my attempts at humor and sarcasm are lost on the carbohydrate deprived. Or maybe too much saturated fat causes osteopetrosis of the funny bone.