Oh Rats!! I: Usefulness of Rat Studies & Sugar Addiction

Over the past several months I have fallen down more PubMed rabbit holes than I care to admit to ... and that's just for the Restriction Addiction book (which, by the way, I'm putting the finishing touches on for republishing the updated and expanded version). Research for that book was overwhelming at times because of the sheer volume of studies out there on food addiction, dopamine, food reward, obesity, eating disorders, etc.etc. A ton of them in rats. No ... my book is not a lengthy compendium with 1000 references. There are a few seminal reviews that illustrate key points.

One of these is the following from Nicole Avena PhD. :  Evidence for sugar addiction: Behavioral and neurochemical effects of intermittent, excessive sugar intake.  The PDF for this is more like a mini-book, complete with sections and content navigation.  So when I was perusing the schedule for the upcoming New Age Paleo CONference and MLM Expo (aka PaleoFX) and saw her name among the speakers I was like ... finally, they bring some cred up on the stage.  

That sentiment was short-lived, because apparently Avena was bitten by a Lustigvirus-carrying Wistar before it was sacrificed for its brain analysis.  That is to say, she has fallen prey to the low carb "science" and militant anti-sugar craze and joined the activist ranks as a hyperbole-laced-fad-diet-book author.  Yes, she teamed up with a Gary Taubes fanman (who lost weight with low carb and dedicated his contribution to the book to Taubes) and wrote a book:  Why Diets Fail (Because You're Addicted to Sugar). The subtitle implies that SCIENCE EXPLAINS all of this.

Well, even if it did, she dedicated less than 10% of the book on what any "science explains" about cravings or anything else for that matter.  It would be generous to say that half of that 10% contained any sort of real explanation of the science behind her diet as billed.  One would never guess reading the book that Avena has been such a prolific scientist in the field.  Disappointing to say the least.  Meanwhile her co-author's made up concept of "sugar equivalency" appears 82 times in the book and the combined sections on understanding the concept and utilizing it to avoid certain foods combine for at least 15%, not counting another 15% in the form of an appendix listing the sugar equivalency of various foods.  (BTW I use percents because in Kindle you don't have page numbers you have locations.  The book is around 3800 locations in length).

What is this SE?  Well it's an arbitary formula whereby or a 100g portion, SE = grams sugars + 0.75* (grams starch).  Because I guess counting carbs is so 2003-ish and this is sure to make this uber-restrictive diet all the more simple to adhere to for life. For anyone interested, her "Sugar Freedom" plan is basically to slowly wean yourself off of sugar.  First ditch the sodas, then the junk foods, then drastically reduce carbs (Atkins Induction style) ... and eat that way for the rest of your life!  Voila!!  I wonder if she'll get to chat sugar addiction with the Sugar Detox Green Apple Pusher ... because ultimately the plan is to severely limit anything with an SE above 5.  Apples, it turns out come in at an 11.  So those addictive little buggers are out.  Heck, it's a good time for this meme.

But I digress ... I'll have quite a bit more to say about Avena's work in the coming weeks with the re-release of the book.  Because the bottom line is that the way they get rats to consume a lot of sugar is to put it in their water supply, and the way they get them to binge on it is to restrict their access to it and make it available several hours into their active period in their circadian cycle.  Avena developed that animal model and is well familiar with the results.  The rats that binge (display signs of "addiction") merely consume larger quantities of sugar over shorter periods of time, ultimately consuming no more than ad libitum rats when averaged out over the 24 hour period.  And here's the kicker folks, the rats compensate for the sugar calories and eat less chow so that ...drum roll please ... they don't become obese whether they binge or not!  Avena has seen this first hand as a graduate student and post doc.

Now, I can understand how someone who has observed human behavior may think that sugar consumption in liquid form may increase intake, but Avena knows that it doesn't in rats -- even rats that "binge" on sugar.  One might postulate that this is because humans are not rats, but in her book Avena writes:  
Most of the science suggesting that excessive intake of sugars can result in signs that resemble an addiction comes from laboratory studies conducted with rats. Although we look very different, rats are actually very good models of humans because we have similar brain systems and neural circuitry. Rats are used to study many disorders and diseases that affect humans, including those related to feeding behaviors and addictions. Pharmaceutical drugs that are developed for humans are almost always tested in rodents before they find their way into clinical trials, as rodents are generally thought to provide a good indication of what is likely to happen in humans in similar situations. Why are rat studies important? Researchers using animal models don’t have to worry about the potential influences of the environment, media, or cultures on the behaviors or brain changes they observe. It is a great way to isolate the variables of interest and minimize outside influences that could affect the results.   [Kindle Locations 1084-1091]

Well then, if they are, and humans behave differently, perhaps it's one or more of those other "potential influences" rather than sugar.  

Eh ... there are books to sell give away :-)

Three word review of book:

Save Your Money!

In Part II,  rats are elevated from "very good" to "great" models for humans as we try to blame refined carbohydrates and sugar for obesity and laziness. 


MacSmiley said…
Somebody must be pocketing some serious money to write bibles for such Taubes/Atkins/Lustig worship.
charles grashow said…

Q. A lot of the recipes in your book use fruit to add sweet flavors. Was this a way to limit refined sugar?

A. Exactly. People always say to me, “What about fruit? It has sugar.” But I have nothing against fruit, because it comes with its inherent fiber, and fiber mitigates the negative effects. The way God made it, however much sugar is in a piece of fruit, there’s an equal amount of fiber to offset it.

There’s only one notable exception: grapes. Grapes are just little bags of sugar. They don’t have enough fiber for the amount of sugar that’s in them. But I have nothing against real food, and that includes real fruit. Eat all the fruit you want. It’s only when you turn it into juice that I have a problem with it, because then it loses its fiber

Dr Robert Lustig - "EAT ALL THE FRUIT YOU WANT!!!
Bris Vegas said…

Summary: Sugar AND fat combined are very bad. Sugar by itself isn't too bad.

Humans evolved from frugivorous apes so you would expect us to be extremely sugar and carbohydrate tolerant but have poor fat tolerance [wild chimp diets are ~6% fat].

Interestingly enough the longest lived people on Earth (Okinawa) have an ultra-high carbohydrate plant-based diet with very low (10%) fat intake (just like wild chimpanzees).
carbsane said…
This fits in perfectly with Avena's recent appearance on KTLA. http://ktla.com/2014/04/08/why-diets-fail-because-youre-addicted-to-sugar/#axzz2yKyJ0Hjd

Maybe that link will embed, but otherwise it's fairly short. The audio is choppy (might be my browser at the moment) but just before the 3 min mark she says if you're going to have sugar you are better off getting it from a fruit because it has fiber and fiber mitigates the effect on the brain. Then they go on to the yogurt which -- add in your own fruit. Then on to the Craisins (these are stupid, they aren't dried fruit, they have sugar added, let's be real about what is what). This is the hilarious part though because an "expert in nutrition" according to the book bio actually says that when you dehydrate a fruit you're "sucking all the fiber out". Plus they may contain added sugar. The latter is real, but that's what labels are for and if people don't know by now to check ingredients on fruit juices, canned or frozen cocktails and mixes or dried fruit stuffs, well that's not the fruit's fault.
charles grashow said…

"Of course, it may not be only what they’re eating; it may also be what they’re not eating. “Are they doing something positive, or is it the absence of something negative?” Gary Taubes asked when I described to him the Ikarians’ longevity and their diet. Taubes is a founder of the nonprofit Nutrition Science Initiative and the author of “Why We Get Fat” (and has written several articles for this magazine). “One explanation why they live so long is they eat a plant-based diet. Or it could be the absence of sugar and white flour. From what I know of the Greek diet, they eat very little refined sugar, and their breads have been traditionally made with stone-ground wheat.”

BUT - aren't CARBS BAD!
carbsane said…
Which is why I made this crude meme yesterday
charles grashow said…

Was it due to the low fat intake of the fact it was calorie restricted?
charles grashow said…
Sanjeev Sharma said…

> Who goes paleo? And Why?
•“A Special Kind of Person”
Part I:
Who goes paleo? And why?
Sanjeev Sharma said…
or, like Dr Kate, one could choose to not believe the data
Better yet, was it severe and conscious calorie restriction or unconsciously lower-ish intake that most of these folk on fad diets tout as the exclusive miracle aspect of their respective 'products'?

The Thai study is rather telling--lowered calories and increased fat and decline in metabolic health--and the point remains that despite a not so grand restriction in calories, the Okinawans didn't deteriorate from glycaemia, limpemia or SFA deficiency.

"No! That's impossible"

"Uh. I've got the paper right here!"

"No way, dude!"
charles grashow said…
Since the study was based on food consumption circa 1950 one can assume that post WW2 food problems had something to do with the caloric restriction
carbsane said…
Interestingly, calorie restricted rodents throughout life don't seem to have issues either.
Wasn't the calorie restricted rodent thing related to IGF-1, though? Can't be sure.

There was something posted a while back, I don't know where and when, so this is purely speculation talk.

A bit of intermittent elevation of free fatty acids is a good thing, but beyond a certain point--and this isn't the broadest window--it can become more of an issue. So if one were to calorie restrict, which is the better option? Higher fat intake or higher carbohydrate intake? I think if one can calculate their minimal fat and protein requirements and meet them, then the rest--in such a restriction scenario--should, ideally speaking, go to carbohydrate so that FFA-release is more tightly regulated while glucose metabolism and thyroid function are somewhat maintained. Of course, this could be totally wrong and the view of elevated FFAs could be falsely masking something that might be of benefit to humans in a novel, modernised environment. However, even these recent papers that have presented an exoneration of SFA have citations within them about elevated FFAs having independent relationships with poor metabolic and cardiovascular health.

This leaves us with the many anecdotes, which mean very little, but one can look into them for some trends anyway. There's plenty of examples of people getting themselves down in weight and even embarking of intermittent fasting with various dietary protocols. The one thing that doesn't seem to pan out so well for those on the low carbohydrate and high fat diets is that despite very reputable weight loss, the lipids and glucose metabolism actually look worse, even into the long term, until and unless some of that carbohydrate restriction and fat intake isn't moderated. Again, perhaps we need a whole paradigm shift on the matter, but as it stands, interpretation of evidence and metabolic understanding seems to lean in favour of one fuel over the other, inside and outside calorie restriction scenarios.
carbsane said…
My apologies for being a bit scattered in the brain from the family situation. Normally I could rattle off the study and find it, but a quick check didn't turn it up. So from memory, I was looking at a number of papers on starvation metabolism and it is clear that if one consumes roughly 100g of *real* carb (not 2 g here and there from spinach and mushrooms) this preserves lean mass as well as electrolyte balance. The whole broth thing for ketoadaptation is to counter sodium dumping.
No worries and thanks for the response. I have read about the 100 grams of real carb approximation from a few sources. It is considered the sweet spot to avoid muscle wastage and preserve electrolyte balance, even for those indulging in low carbohydrate eating with body building and fitness in mind. It does scale a bit depending on level and intensity of work outs.

The bit was I referring to, vis-a-vis Minger's post, was specifically regarding glycine supplementation mimicking the life extension benefits of methionine restriction... in rats.

Title: Dietary glycine supplementation mimics lifespan extension by dietary methionine restriction in Fisher 344 rats

Authors: Joel Brind1,2, Virginia Malloy2, Ines Augie2, Nicholas Caliendo2, Joseph H Vogelman2, Jay A. Zimmerman2,3 and Norman Orentreich2
Hello_I_Love_You said…
Speaking of sugar, check out this Food Summit taking place in 10 days. It has all the vegetarian gurus (Ornish, Esselstyn, Barnard), Mark Hyman and Robert Lustig, plus Woody Harrelson. Wow, Hyman and Lustig do get around.

Here's theme for the summit: "Get the truth about GMOs and dangerous chemicals — and how carbs, gluten, fat, and sugar affect your weight, energy, sleep and the planet." Carbs and fat, that only leaves protein as the benign macronutrient.

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