Admission by Gary Taubes that he was wrong about carbs being required to store fat
Lex, if I understand correctly, your journal experiment was inspired as a test of Gary Taubes' hypothesis that people can't add body fat from eating fat in the absence of carbs and that calories are therefore irrelevant on ZC. Gary Taubes revealed in the interview below that this hypothesis wasn't stated explicitly in his book, but that he did propose it in his old lectures (before he revised them). Although he did write in his book, "Dietary fat, whether saturated or not, is not a cause of obesity" and "carbohydrates make us fat and ultimately cause obesity." Based on the interview, I think he still believes these points, as he apparently sees fat as much less of a factor than carbs.
Taubes has at least partially recanted his hypothesis, though he claims that the exception of glycogenolysis (the degradation of glycogen) and probably the production of insulin from excess protein intake (
http://jcem.endojournals.org/cgi/content/abstract/81/11/3938) [and the one previously mentioned in this forum--gluconeogenesis ("the generation of glucose from non-carbohydrate carbon substrates such as lactate, glycerol, and glucogenic amino acids." (
http://en.wikipedia.org/wiki/Gluconeogenesis)--and who knows what else]. You apparently found that your experimental results disproved the hypothesis. Gary even mentioned that some bloggers had refuted it, and who knows, maybe you were one of the people he was referring to.
In my opinion you've basically been vindicated, though Gary apparently learned of his error from some scientists some time ago, according to him, and I suspect that there is more to this than Gary has discussed, including more beyond what I've added with a little searching.
A (Cooked) High Fat Diet Can Cause Obesity and Atherosclerosis
Alpha glycerol 3 phosphate enables the storage of triglycerides in fat tissue. Both carbs and the glycerolneogenesis of dietary fats can produce Alpha glycerol 3 phosphate. Thus gluconeogenesis and glycogenolysis can cause body fat gain and dietary fat can provide the raw material for gluconeogenesis and glycogenolysis. A high-fat diet in mice produced the liver lipid metabolites hepatic triacylglycerol and diacylglycerol (Study reveals trigger for insulin resistance in liver, potential drug targets,
http://www.medicalnewstoday.com/articles/27763.php).
A (cooked) high fat diet can cause hepatic insulin resistance. Hepatic insulin resistance "is sufficient to produce dyslipidemia and susceptibility to atherosclerosis (
http://www.cell.com/cell-metabolism/abstract/S1550-4131(07)00368-3). Hepatic insulin resistance also causes "an increased rate of production of glucose, due to gluconeogenesis and glycogenolysis." (Arner,P. 2002. Insulin resistance in type 2 diabetes: role of fatty acids. Diabetes Metab Res. Rev. 18 Suppl 2:S5-S9.) And thus the circle is complete.
Gary Taubes basically admitted to it here (though he includes some defensive language, but after this excerpt he makes some rather astounding and candid concessions that may lose him hundreds or even thousands of potential readers:
41:05 [He made a mistake in his lectures, not in his book. In his older lectures he] talked about glycerol 3 phosphate (alpha glycerol phosphate) being raid?-limiting and that you need carbs to provide the glycerol 3 phosphate to store triglycerides in the fat tissue, so therefore the more carbs you have the more fat you store, which turned out to be wrong. Glycerolneogenesis [sic; glyceroneogenesis] can produce glycerol 3 phosphate.
45:56 [However:] "Insulin so fundamentally determines fat accumulation, that it doesn't really matter. … The more carbs, the more alpha glycerol 3 phosphate, the more fat you can store. That's all still true, but you can store fat without the carbs and in fact you
have to be able to store fat without the carbs, because you're constantly recycling fat and you release more fat into your bloodstream than you're gonna burn in any one period of time [Plus, as I pointed out some time ago, not being able to make fat from fat would have made life for Arctic peoples very difficult if not impossible]. So much of the fat that you release into the bloodstream is fatty acids, [which] end up back in your fat tissue being stored again as fat. So you have to be able to do it. … And I always knew you had to be able to do it, but somehow, in the lectures, <pphhh> it got a little skewed…."
http://www.thelivinlowcarbshow.com/shownotes/2403/the-return-of-gary-taubes-episode-401/Gary seems exhausted and depressed in the interview. I felt bad for him while listening and still do thinking about it. No doubt he's been put through the wringer due to the firestorm that his controversial views ignited and the way the LC thing has taken over his life. [I empathize with Gary and I'm not looking for an argument with any of his defenders, though if anyone has corrections to make or info to add, please let me know. Thanks.]
Things seem to be tilting the raw Paleo way lately, what with Stephan Guyenet and Dr. Davis writing about AGE's and now Gary Taubes publicly admitting that (cooked) fat intake can create body fat.
I threw this together, so I've probably made errors and feel free to correct them.