Calories, fat or carbohydrates? Why diets work (when they do).

It was inadvertently (I think) brought to my attention that, while constructing my Fasting Insulin & Weight Loss post, I had "in my hand" the perfect study to discuss the title of this post.

Does that title sound familiar?  It should!  Because this was the title of Gary Taubes' second blog post:
Calories, fat or carbohydrates? Why diets work (when they do)

As I've stated many times, unless someone provides me with a complimentary copy of Why We Get Fat, I'll not be reading the dumbed down version of GCBC, even for the groundbreaking new information it is purported to contain.   Reportedly, one of those groundbreaking items is a chapter on the very topic of that blog post.  A blog post that was a sort of preview teaser in advance of his book release.  But that post wasn't the first time he discussed this novel idea that he claims supports his alternate carbohydrate/insulin hypothesis.  

Most of my readers are probably aware of when ol' CarbSane here really hit Gary below the belt by playing on words,  "called Gary a sheister", and - GASP! - put a $ in his name, when I addressed his discussion of Shai in a lecture.  I guess the plays on words there using Shai-ster and Shai-t were just too much for his devoted followers to handle.  Who knew a $ could draw such ire!  I suggest if any of these things are going to throw you into ketogenic paranoid seizure, you click on that X in the upper right corner of your browser now.

Really ... I mean it!  DON'T click the "Read More" below if you can't handle it!!!  I'm gonna get nasty here!

Really really.

OK ... last warning (VVVBEG)

[ profanity warning] Or, you could grow a fucking pair, wipe the shit off your face from having your head up your ass for so long, and read on without all the Gary damned whining.  Crude enough for you?  Just channeling my inner Nikoley ;-)  I hear low carbers like this sort of thing from their bloggers ... but I digress ...  [ /profanity ]

Sorry folks.  Sweet li'l old vitriolic me is back.

  

In any case, here was my post:  Gary Taube$, Shai-ster  Gird your loins if need be and go read that post before reading on.  As a special treat, if you follow the links to Gary's lecture, you'll get to hear his now infamous gluttony quote.   Behave yourself Nigee! 

In a nut-shell, Taubes compares just the LC and LF groups in the Shai study.  He ignores the reported calorie deficit of the LC group, implies they ate more but lost more weight, and he attributes this to the fact that it is carbohydrate restriction that produces weight loss.  This, he says, is why the LF group lost some weight, but less:  they also reduced carbs but not as much as the LC group.  

Now, since I didn't stress this strongly enough in my original post, I will state it definitively now:  The dietary intake data from the free-living Shai study is, ultimately, USELESS to draw any conclusions regarding energy balance or attributing results to a particular variable.   A few days self-report for some of the subjects at 3 time points over a 2 year period just doesn't cut it!   

And yet in his blog post, after acknowledging just that (" the dietary records from these studies have to be taken with a grain of salt"), Gary goes on to base his entire argument on the basis of such flawed data.

Taubes:  Let’s concentrate on the low-fat, calorie-restricted diet and the low-carb, Atkins diet. The changes in dietary intake and nutrients for the “low-fat diet” are shown in the first column. As you can see after 24 months, the subjects eating the low-fat diet were supposedly restricting calories consumed on average by 572 calories. The reduction in carbohydrates consumed, though, was 330 calories (82.8 grams per day times 4 calories per gram), compared to only a 170-calorie (18.9 grams per day times 9 calories per gram) reduction from baseline in fat. So the “low-fat diet” reduced carbohydrates nearly twice as much as it reduced fat.

The low-carbohydrate diet, on the other hand (the third column), reduced carbohydrate calories by 520 calories per day (129.8 grams per day times 4 calories per gram) and fat calories by a mere 15 calories (1.7 grams/day times 9 calories per gram). So certainly the low-carb diet was correctly described as a low-carb diet, and the question we have to ask is maybe the weight loss seen in the low-fat diet was also due to the restriction in carbohydrates. 

Me:  Let's look at ALL of the data.  The Mediterranean diet, reduced carbohydrate calories by 202 calories per day (50.5 grams per day times 4 calories per gram) and fat calories by 95 calories (10.5 grams/day times 9 calories per gram). 

To summarize:  Total Calories/Carbohydrate Calories/Fat Calories we have: 

LF:   572/330/170                MDTN:  372/202/95                LC:  551/520/15

At 2 years, average LC & MDTN weight loss was the same and a bit more than the LF group.  Which tells us jack squat.

Taubes waxes sanctimonious over Shai and her colleagues painting them as some sort of clueless researchers who have never heard of confounding variables or how to control for variables in their study.  Poor Iris Shai, RD, PhD.  She'll never garner the respect of Mr. Gary Taubes until she analyzes her data to his high standards.  

It turns out that Shai's variable (singular) was simply the dietary intervention.  Period.  My take is that such studies as this are instructive to provide us with determining what type of intervention may be successful for the greatest proportion of people, for the long run, in real life.  As such, Shai couldn't even rigorously control for whether the participants adhered to their assigned program 100% or anywhere near.  That's the rub with all free-living studies.  They should never be used, then, for analyses that require data obtained in the constructs of such rigorous control.   If I have any criticism for Shai it would be perhaps that more detailed dietary records could have provided better insights.  Even self-report.  One day per week per subject for the entire study?  How about a 3 days each month per subject averaged?  Because the data, as they are, do not jive with the weight results, or Shai definitely doesn't look good for the low carbers:  significant gain back despite slightly increased carb restriction.  

So Taubes goes on:

It is quite possible that even low-fat, calorie-restricted diets work because they restrict carbohydrates and maybe the reason they don’t work as well as the low-carb diets is they don’t restrict them as much. Or maybe they don’t work as well, on average, because they also restrict fat calories when dietary fat has little or no effect on body fat accumulation. We don’t know if this is true or not, but it could be true, and until these researchers realize that another variable is changing significantly on these low-fat, calorie-restricted diets –  the amount of carbohydrates consumed — they’ll never bother to test it or take it into account in their interpretation of these clinical trials, and we’ll never know.

Go back and read the beginning of his post. 

... the value of controlling variables in a scientific experiment is something that a reasonably well-educated child supposedly understands. And what I want to know is why don’t nutritionists understand it and those researchers out there doing diet trials and studying obesity and weight regulation. Because their failure to do so — and I would argue that it may be a willful failure — has led to what may be another of the great misconceptions in modern nutrition research. In particular, that carbohydrated-restricted diets are “valuable tools” in the arsenal against overweight and obesity, but they’re just one of the dietary tools.

His usual condescension towards anyone who doesn't see things his way is apparent.  It's so simple, even a child can grasp it., but Shai is such a do do bird she and every other nutritionist or researcher just don't get it. This from a man who gave us that rigorous analysis (leaving out 1/3rd of the data) of data he, himself, states should be taken with a grain of salt.   Worse yet, he essentially accuses them of worse than stupidity, but willful failure.  OK, so it's fine for him to accuse millions of researchers and nutritionists of professional malfeasance, but I'm out of line for calling him out on his easily documented professional malfeasance?? 

Let's get back to controlling variables.  Taubes implies - and his followers apparently believe him - that all of these studies have never been done.  To repeat:

We don’t know if this is true or not, but it could be true, and until these researchers realize that another variable is changing significantly on these low-fat, calorie-restricted diets –  the amount of carbohydrates consumed — they’ll never bother to test it or take it into account in their interpretation of these clinical trials, and we’ll never know.

Oh, but Gary, my point is that, they actually HAVE tested this, in innumerable studies, and we DO know.  But Gary's words play to the victim mentality so prevalent amongst low carbers and they gobble it up it appears.

Cue "opening of heavens" music ... Ah AAAAAAAAAAH!

Behold  Grey and Kipnis:   This was an inpatient study where intake was carefully monitored and controlled.   

• Protocol 1 - Effect of Carbohydrate Content in Caloric Balance:  Subjects ate ad libitum for 2 weeks to establish weight maintenance calorie needs ad libitum period, then fed at that caloric level for 3 weeks on a LC diet (C/F/P = 25/53/22), and switched to a HC diet (C/F/P = 62/18/20) for the final 3 weeks.    

So G&K's study design, to a well-educated child, controlled for calories and protein (slight differences), varied the carbohydrate/fat content of the diet and measured body weight, fasting insulin and glucose stimulated insulin secretion.  What did we find?  Apparently one subject refused some food and lost a bit of weight (apparently another gained ever so slightly too), but overall, the isocaloric diets maintained bodyweight independent of the carbohydrate content of the diet.  

• Protocol 2 - Effect of Carbohydrate Content in 1500 cal CRD:  Here the subjects again established baseline for 2 weeks and were then cycled between 1500 cal formula diets:  4 weeks HC (C/F/P = 72/1/27), 4 weeks LC (C/F/P = 0/74/26) and finishing up with 4 more weeks HC.

Now I know it's probably lost on Grey and Kipnis, but again, our well educated child would immediately note that this IS a controlled study!  You can't get much better than this in terms of controlled study design.  My only qualm is the small sample size and that this was a rat study.  Oh wait ... correction ... they were human females.  The researchers used formula diets which basically minimizes differences in digestion on absorbed calories, controlled their intake in a supervised setting, controlled for total calories and protein, and compared an essentially fat-free diet to a zero-carb diet.  

The result?  All subjects lost weight in steady fashion despite the wild swings in the carbohydrate consumption.  And, an extra bonus, the two subjects with higher baseline caloric intake lost more than the subject with lower maintenance calories.  

CONCLUSION:  Controlling for calories and protein intake and varying carbohydrate/fat composition of the diet resulted in weight maintenance with intake at individualized maintenance caloric levels, and weight loss with intake at caloric deficit.  Diets work (when they do) when there is a consistent sustained caloric deficit.

S L O W L Y   N O W   F O R   T H O S E   S U F F E R I N G   F R O M   C.D.S:  

A study was done that controlled for calories (and as a bonus, protein) and varied carbohydrate content and measured weight loss.  Result:  weight loss was consistent independent of varying carbohydrate intake between basically all of non-protein calories and non of all-protein calories.  

Now I realize 1971 is a bit too contemporary for Mr. Taubes, but since he did reference a text published in 1972 he could have found this study were he interested.  

I think Mr. Taubes owes Drs. Grey and Kipnis an apology for his unprofessional, unethical, and downright below the belt assaults on their scientific abilities and integrity!  Don't you?

More installments may be forthcoming as needed.

Edit - Followup Posts:
Fasting Insulin & Weight Loss II
GCBC Reference Check ~ Part IV of ? ~ Kipnis