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Sunday, November 27, 2011

Taubes' Rat Problem

No ... rats have not infested Taubes' batcave replica of the AHS lecture hall.  Rather, Gary steps in it yet again with his discussion of the Cafeteria rat study in one of his lame attempts to debunk Stephan Guyenet's works on food reward.   The Cafeteria rat study he was referring to is, in my opinion, the most relevant animal study on the etiology of the modern obesity epidemic in Westernized countries.   Let's revisit the study with a post of mine:  Why We Get Fat ... Lessons from a Cafeteria Rat.  In short, you can get "normal" rats to become fat by replacing their usual chow with a high fat chow and/or a high sugar-containing chow.  But how do you get them to become really really fat?  Feed them modern American junk foods.  I'll repost some pertinent graphics from that post here.  The so-called "cafeteria rats" were provided ad libitum standard chow along with a rotating selection of three items from the list below:

I think that's a typo there between the Cheez-Its and Doritos, Cocoa Puffs were already listed at a more realistic macro content.
What happened?  The ratties eschewed their normal chow and nibbled away (and away and away) at the junk foods.  How much did they eat?  See below:

*missing carb count on SC calculated to be 110.5g
The  HF fed rats actually ate slightly less than the SC or LF fed rats (who were actually high sugar fed), but the CAF rats consumed over 35% more calories.  And what happened?  Well, again, see below:
The LF & HF rats gained a bit more than their SC counterparts while the gluttonous CAF's became obese.  Also, I just noticed that while the other rats appear to be leveling off some in weight, the CAF rats appear to still be gaining after 10 weeks.  

I am really beginning to wonder about Gary, because, rather than reading the Sampey study Stephan is referring to, he preferred to cite another researcher, Sclafani.  The manner in which he does this is misleading to the reader as it implies that Sclafani conducted the research in question.  Here's what Taubes says:
Now, how about the idea that a “cafeteria” or “junk food” diet makes humans and animals fat, a concept that was pioneered by Anthony Sclafani. The assumption is that such a diet is fattening because there’s something about eating a variety of foods, mostly junk foods, that is so rewarding or at least so less bland than a plain chow diet that both humans and animals get fat eating it. Here’s how Dr. Guyenet describes it:
In this model, animals are allowed free access to standard chow and water while concurrently offered highly palatable, energy dense, unhealthy human foods ad libitum. 
In other words, they’re given an unlimited amount of human junk food in addition to their whole food-based “standard chow.” In this particular paper, the junk foods included Froot Loops, Cocoa Puffs, peanut butter cookies, Reese’s Pieces, Hostess Blueberry MiniMuffins, Cheez-its, nacho cheese Doritos, hot dogs, cheese, wedding cake, pork rinds, pepperoni slices and other industrial delicacies. Rats exposed to this food almost completely ignored their healthier, more nutritious and less palatable chow, instead gorging on junk food and rapidly attaining an obese state.
Aside from Dr. Guyenet’s description of standard rat chow as “whole-food based,” my major problem with this (which is the same problem Ramirez et al had 20-odd years ago with the existing research then) is that this is an experiment that changes an unholy host of variables, and the results are evoked to make a point about one: food reward value.
I'm not sure how an osmotic effect theory, apparently advanced by Ramirez (I can't get the full text and the abstract offers little information), but this is again Taubes employing distraction tactics.  The Sampey study to which Stephan was referring doesn't really "change an unholy host of variables" at all.  They changed the type of food by macro composition (the various chows) and then tested the modern food supply.  I really don't know how much plainer than day the point can be made at this point.  The rats did not overeat because their fat cells were accumulating fat on the HF and LF(HSucrose) chows.  They overate the human junk foods.  Occam's Razor would say the obvious culprit here is not the macronutrient makeup, but something else about the food.  

Rather than discuss the study and its implications, however, Gary waxes poetic about one of his advantages as a journalist.  That is, instead of reading the scientific publications, he can just call up the scientist and shoot the breeze (and basically tell us anything he wants to about what they said because there's no way to really challenge a he-said/(s)he-said conversation).  So we learn that in 2003, Gary talked to Sclafani about the cafeteria rats.  Here's how that went:
As Sclafani told me, they started their cafeteria diet (which he was calling the “supermarket” diet at the time) with a variety of different foods (not quite as wide a variety as Dr. Guyenet is discussing above, but wide nonetheless): chocolate chip cookies, salami, cheese, bananas, marshmallows, milk chocolate, peanut butter and sweetened condensed milk, and then they later simplified it to four foods because the rats didn’t eat all the foods they gave them.

Which foods did they ignore? Sclafani said they never did a systematic study, nor had anyone else, as far as he knew (as of January 2003), but cheese, salami and peanut butter—the foods highest in fat and lowest in refined grains and sugar—seemed to be the foods they avoided in favor of the sweeter, starchy options. So the obvious question: are refined grains and/or sugar necessary to impart not just reward value, but reward value that leads to people and animals getting fat?
That bolded part has to be one of the most aggravating habits of Taubes.  That is, suggesting that we don't really know the answer to that question, or the study hasn't been done, etc.  At right are the macro % breakdowns of the four diets, and above are the foods and the simple sugar contents of the foods/diets.  The CAF rats ate roughly 15% of their food from the chow which was quite low in fat, thus they must have been eating the majority of their CAF foods from the lower half or so on the food list to end up with a diet that was 44% fat.  At under 10% fat, the Fruit Loops and Cocoa Puffs weren't doing it.   Now this study did not assess just exactly which particular foods caused the rats to eat more, but clearly they weren't those highest in refined carbs or the sweetest.  It bears repeating that the LFD was matched to the HFD by replacing 35% of the fat calories with sugar calories in the form of sucrose.  The rats actually ate slightly less of the HFD than the LF(HSug)D but gained roughly equal amounts of weight.  Not only does this counter TWICHOO, it counters FrucTWICHOO as well!  Taubes is stuck in a sugar rut methinks.  Sure it would be nice to know what the amounts of each junk food consumed were, but to assume as Taubes implies that they would have left the cheese, pepperoni, hot dogs and pork rinds alone doesn't seem reasonable.

It's pretty obvious why Taubes avoids discussing this study specifically -- it trashes not only TWICHOO, but his newer refined-carbs and sugar parachuted version as well.  Taubes seems to be saying that if there's anything to this food reward thing, it must really be that it's the carbs that are rewarding.   This study doesn't support that assertion.  To address it would provide more Gary Debunks Taubes plays, and I doubt he wants that.

TWICHOO does not explain why the CAF rats get fat.  They ate the lowest amount of simple sugars, a significantly lower % carbohydrate than the SC and LF rats, yet they become the fattest.  Why?  Because they overeat ... plain and simple.   That food reward is likely not the only factor doesn't bother me.

Meanwhile, I don't suppose Taubes will be putting his journalistic advantage to work anytime soon to get the real skinny from Sampey.   By not addressing it, however, Taubes' rat problem is likely to do what rats tend to do when left alone in a "food" rich environment.

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