Matthew:

I like the rat study you linked (Woods 2003), because it bolsters my point: the low-fat purified diet group ate non-significantly fewer "calories" than the regular chow group, but weighed about 10% more by the end of the experiment.

I agree: it's annoying that Romestaing et.al. didn't come up with a more accurate measurement of total bodyfat. 

I do note, however, that the coconut+chow rats did not develop fatty liver, so the odds are that they did not develop lots of mesenteric fat either.  And since the rest of the paper is trying EXTREMELY HARD to dredge up harmful effects of the butter and coconut diets, I suspect that the increase in total bodyfat did not parallel the increase in retroperitoneal fat.

Seriously: there were only four rats per group -- and there are many accurate ways to measure bodyfat that are far cheaper than a DEXA scan, especially when the animals are dead (see Dahms 1982 for more information.)  For instance, they couldn't be bothered to put all four dead rats in a blender and separate out the fat, which is how such measurements are typically done...but they had time to surgically excise one single fat pocket the size of a teaspoon from each rat (which comprises perhaps 15% of total bodyfat), measure it accurately, prepare slides, and compare adipocytes under a microscope?

That smells like shenanigans to me...

...like they were trying very hard to engineer the results to show some harmful effect of the high-fat diet, because Everyone Knows a rat that eats over twice as many "calories", many of them in the form of ArteryCloggingSaturatedFat from coconut oil, simply must have something terribly wrong with it!

Anyway.

Moving on: I still contend that one-twentieth of a teaspoon of brown fat cannot be responsible for burning off 105 kcal/day -- more than the entire rest of a 450-gram rat.

Let's do some math: one kcal raises the temperature of a kilogram of water by 1 degree Celsius.  67.5 milligrams (the extra brown fat that the coconut+chow rats possessed) goes into 1 kilogram about 15,000 times.  Therefore, 105 kcal would raise the temperature of 67.5 milligrams of brown fat by about 1.5 million degrees Celsius.

I rest my case.

JS

Bill:

Thank you!  I like your hypothesis that small changes in nutrient partitioning are primarily responsible for fat accumulation in the long-term.

For my readers: Dr. Lagakos writes at http://www.caloriesproper.com

JS

"EatLessMoveMoore"/"Melissa"/"CarbSeine":

Just as I told you before: "Don't expect a response to sockpuppeting or gratuitous pot-stirring."

JS

John:

Thank you!  There's more to come, too.

JS

Chris:

Click on the (Fulltext available here) link in my original citation and you'll be taken to the Nature website, with fulltext and all the graphs.  Pubmed only has the abstract.

JS

david:

AFAIK Feinman's point is that the "metabolic advantage" shown in some low-carb diet trials is due to the inefficiency of gluconeogenesis.  This is plausible.  However, as I discussed in Part I, gluconeogenesis is just one of many possible fates of dietary energy.

There are two parts to the calorie fallacy: "a calorie is a calorie" and the "3500-calorie rule". Multiple studies directly disprove both of them: for the 3500-calorie rule, see Part II, and for "a calorie is a calorie", see all the parts in the series!

JS