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Sunday, March 31, 2019

Guyenet v. Taubes ~ Topic 1: "Just 10-20 Calories a Day"



Unless you've been living under a "rock" in the world of nutrition, you're aware that Stephan Guyenet "debated" Gary Taubes on the Joe Rogan Experience podcast.





It took me several days broken up to watch/listen to the whole thing. In a nutshell, it was Science & Substance (Stephan Guyenet) versus Stories & Slander (Gary Taubes).

Rather than summarize, there were several points made that I'd like to address. In no particular order. I'll include this intro with links to prior topics as this series progresses.




The "10-20 Calories Difference" Claim


Timestamp: 1:09:49


Gary Taubes makes the extraordinary claim implying that obesity is the result of an extra 10-20 calories per day. He gets picky about semantics -- for a bit anyway -- but elsewhere in the podcast he's back to the reality that to store or accumulate 10-20 calories a day, these must be "extra" and they don't magically appear, they are consumed.

The example begins with putting on 4 lbs a year, and is then boiled down to more round numbers. Let's say you're a lean 20 year old, and you put on 40 lbs between then and the time you turn 40. I'll do the math -- this is gaining 2 pounds per year over a 20 year period. Gary Taubes claims this only requires an extra 10-20 calories per day to accumulate. 


The Calculation:

Stipulated: 100% of weight is accumulated lipid/triglycerides
Stipulated: 1 pound of lipid contains roughly 3500 calories
👉 20 lbs fat * 3500 cal/lb = 70,000 calories
👉 20 years * 365 days/yr (ignoring leap years 😉 ) = 7300 days
👉 70,000/7300 = 9.6 calories/day .... let's round to an even 10 calories/day.

This calculation, or some variation thereof,  has been around for a long time. It is an attempt to reduce energy balance to a trivial matter of measurement error.  It goes something like this:
Q: How can we figure this out down to that level of accuracy?
A: We can't.
But that's not the point. In this debate, we essentially had a brain vs. fat cell as controlling/regulating entity. So the next question is "How can the brain regulate to that level of accuracy?" Here's where Taubes admits that someone is eating these extra calories ... why doesn't the brain tell them to stop? I would contend that this measurement error-level quantity goes both ways. 
Q: How is it that insulin, through refined carbohydrates and sugar, can exact such an impact on the fat cells? 
 A: It can't.



The Great Diversion:



This is all a diversion, however.

We have immutable scientific evidence to counter this nonsense, that all our bodies need to do is hold on to 10 calories per day -- even in the face of relative famine!!! -- to become obese. The evidence is clear. When you reliably measure intake and expenditure for the obese vs. the lean, they consume and expend at higher levels. When you confine humans so that their every morsel and bite can be accounted for, you can determine true intake. When you add more on top of this level, these humans will gain weight. When you restrict below this level, these humans will lose weight. 

Here's where Taubes also shoots himself in the foot with his tautological mental gymnastics of "do we get fat because we overeat, or do we overeat because we're getting fatter". Notice how it doesn't even matter ... we must be overeating to become and maintain a degree of over-fatness. 

Taubes -- ever the story teller -- brings up a friend he had who was 400 lbs at age 18.  This kid, he would have you believe, got some 200 lbs overweight eating a half a cheeseburger or one-to-two Cokes per day more than his lean friends ..... ORRRRR his fat cells just squirreled away that much as he ate the same as his counterparts?? I added that last part, because this is what Taubes implies happened to the Pima women in famine.

Now, Gary's friend was 6'5" tall. So let me run some numbers for you using Mifflin-St. Jeor (this online calculator) to estimate basal energy expenditure, and multiply by a conservative general activity factor of 1.5 to estimate total energy expenditure, TEE.
  • At 400 lbs, Friend has an estimated BMR of 2952 cal/day, and a TEE of just over 4400 cal/day
  • At 200 lbs, Friend would have had an estimated BMR of 2045 cal/day, TEE just under 3100 cal/day
In order to maintain his 400 lb self, Friend would have to consume 4400 cal/day.  If he consumed less, he'd lose weight.  If he consumed more, he'd gain weight.   He is consuming roughly 1300 cal/day more than his 200 pound self would require to maintain a normal weight.  For those doing Taubes' burger math, that's like two Big Macs ... not a couple of bites of a cheeseburger.

I would remind folks David Ludwig used the same Mifflin-St. Jeor BMR equation and 1.5X activity factor to estimate baseline energy needs in the $12M NuSI study he led.  The calorie level to achieve a 12% weight loss target in 12 weeks (more like 10% in 10 weeks) based on this formula amounted to  90% of BMR.  Even the calorie deniers don't deny calories all of the time!


The Total Excess Time to Accumulate is Irrelevant


If you want to talk about what's relevant and what's not in this whole obesity discussion, Taubes' calorie math averaging out the cumulative caloric excess to store a certain amount of excess fat over a certain time interval is what is irrelevant.    It is not the rate or size of caloric surplus, but its very existence and chronic nature that leads to weight gain and maintenance of a higher weight.


Put another way, if Taubes had first met 400 lb Friend when he was 48, and saw in his yearbook picture that he was 200 lbs at age 18, he might calculate Friend's daily overages at 60-65 cal/day ... or if Friend was 58, only 45-50 cal/day.  Who cares!  By this math, Friend is eating the same as his lean self would have for 40 years if he was 400 lbs by age 18 and remained so at 58.  Ridiculous!  Think about this.  Friend would not have accumulated a single calorie's more of fat in all that time, yet he is severely obese. 

The reality is that each year Friend weighs 400 lbs vs. 200 lbs, not correcting for minor reductions in energy expenditure with age, Friend is consuming roughly 460,000 more calories during the course of that year.    This is a far cry from the less than 4000 more that Gary Taubes would have you believe.  



Oh but he didn't say that!  

You're right.  He didn't.  Not exactly.  But his intent is to have you "conclude" that obesity is not about overeating.  Somehow -- teh insulinz -- your fat cells manage to squirrel away fat, 10 calories at a time, like Peter Gibbons' bank account in Office Space (see here if you don't get this movie reference).


Gary denies it's overeating, and yet equates the obesity to nothing more than an extra couple of glasses of coke or bites of a cheeseburger.




How Weight Gain and Energy Expenditure Works:



After Gary goes on about this -- lamenting why he always seems to store fat in his "haunches" -- Stephan gets a chance to respond.  

First, he corrects the record on the total intake, citing a figure of obese consuming 20-35% more vs. their lean counterparts.  Gary's Friend, here, would actually be closer to 40% more by Mifflin-St. Jeor standards, but he's also severely obese.  

His next point is the more important in relegating this "only 10-20 calories per day" nonsense to the dustbin of irrelevancy it belongs in.   Stephan explains the non-linearity of weight gain (and weight loss).     

Here is the energy balance equation as I like to write it:

Δ Energy Stores = Energy Intake - Energy Expenditure



The "problem" with this equation is not a problem at all, but it does complicate things.  That is, the Energy Expenditure is not a constant, it changes as Energy Stores change.    I put 6'5", 200 lb, 18 year old Friend's specs into Excel with the generic M-StJ formula and generated BMRs and TEEs for tenth pound increments to 201, then one pound increments to 210.  


As our Friend accumulates calories (aka fat) in his fat cells, he weighs ever so slightly more, and must expend ever so slightly more to move that weight around and maintain cellular processes.



If at 200 lbs, Friend consumes 3089 calories per day instead of the 3069 he expends, he will be in a 20 cal/day surplus, and accumulate those calories in the form of 2 grams (plus a smidge) of fat in his fat cells.    This is a continuum, but by the time he's accumulated about 0.15 pounds, Friend is expending roughly 1 calorie per day to support that new weight, and his surplus intake is reduced to 19 cal/day.  By the time Friend has accumulated a half of a pound, he's only in about 16½ calorie surplus, and by the time Friend has accumulated a full pound of fat, his caloric surplus is down to 13 cal/day.

What would actually happen were Friend to maintain his 3089 calorie intake level is that he would keep gaining weight, at slower and slower rates, until he leveled off at 203 pounds.  As you can see from the chart, this is the weight at which Friend's Energy Expenditure is again in balance with his Energy Intake, and he'll stabilize at that weight.  

Stephan tried to explain this to Gary during the podcast, but it went ignored.  In order for that 10 calorie surplus to produce profound obesity, it would have to be above and beyond the ever increasing energy expenditure of the heavier and heavier body.  




However I'm quite sure that this is not the first time Taubes has been challenged and informed about the erroneous logic of his "all it takes is 10 calories a day" diversion.   Kevin Hall is not some obscure scientist toiling away in the bowels of NIH.  He's been somewhat of a nemesis of Taubes' since at least 2010 (when I started blogging).  Kevin Hall was also the highly celebrated lead scientist on the first NuSI funded study ... that is until the results were in.  Kevin Hall is also the developer of the Body Weight Simulator (BWS) and has spoken about the 3500 calorie "myth".  He's talked about this very same thing in the context of weight loss before.  

Unfortunately the simulator doesn't work for weight gain, but we get somewhat similar results looking at losing from 203 to 200 pounds (calorie estimates are nominally lower using the BWS).  We see that to lose 3 pounds in a year requires a 50 calorie deficit per day from baseline.  


In order to maintain
your current weight,
you should eat:

3,073

Calories/day
To reach your goal of 
200 lbs in 365 days,
you should eat:

3,023

Calories/day
To maintain your goal
of 200 lbs,
you should eat:

3,041

Calories/day



Note, the body weight loss is not linear but is rather leveling off.  For larger weight losses this is more profound.  The red line on the second graph is expenditure and you can see that as TEE decreases with weight loss, the Energy Deficit declines, hence the rate of weight loss slows.    Once at 200 lbs, Friend could increase his intake to 3041 calories.  Thus, the net caloric reduction over the loss of 3 pounds is roughly 32 calories less per day than 203 lb weight maintenance intake. 

Note:  the calorie differentials are quite different from M-StJ and the BWS.  In playing around with the BWS, it appears it factors in an additional degree of adaptation for greater weight loss (the maintenance level for 200 lbs goes down as the starting weight goes up, for Friend starting at 400 lbs, his ending intake to maintain 200 lbs would be only 2846 vs. the 3068 calculated for a 200 lb start weight).  This gets us into the real weeds of weight management and the reasons for weight loss plateaus, "settling points", and such, but the one thing it does not do is nullify energy balance. 

Bottom Line:  To go from 200 lbs to 400 lbs requires the eventual consumption of roughly 1300 calories more per day on Friend's behalf.  He may get there super slowly by eating *just* 10-20 cal/day over his current (ever increasing) daily expenditure, but that that is on top of the ever increasing tens-to-hundreds-or-more calories he must consume to simply maintain his increased body weight.  

If all Friend did was consume 20 calories more than his lean counterpart (or 200 lb self), he would eventually gain about 2-3 pounds and level off around 202-3 pounds.

The only way 200 pound Friend becomes 400 pound Friend is if he continually bumps intake above his new, higher, energy expenditure (needs).  

There is, of course, a lot of nuance to this story.  For the same BMR, activity levels can make for greater or lesser differences in expenditure per pound, as can large changes in body composition, etc.  In one article, Kevin Hall puts the figure at 55 cal/pound for weight loss.   Unless I'm reading too much into this, that figure is inflated somewhat by the rate of weight loss, and does not reflect the net change in maintenance intakes.    His own BWS seems to consistently "before and after" TEEs at a differential of roughly 10 calories per pound of body weight, while M-StJ x 1.5 puts it closer to only 7 calories per pound.  My own informal overview* of the many studies reporting TEE before and after weight loss seem to point to that 10 cal/pound difference being a pretty darned good one ... a reasonable place to start.  (* very informal, but this is of interest to me, so any time I look at a study reporting energy expenditure, I take note)
                            
Clearly, these are all estimates and "your mileage may vary".  I don't want to clutter this post any more than I already have here.  Suffice it to say, those who are familiar with energy balance past the simplistic rule of thumb -- 500 cal daily deficit = 1 pound per week loss -- are aware of these nuances, and that expenditure is a variable and moving goal post in the energy balance equation.  This does not invalidate the role of Energy Balance in weight maintenance or give any credence to the notion that insulin-crazed fat cells turn to fat hording rogues.
Gary Taubes has nothing but stories and a hypothesis that, in the end, no better explains why some people get fat while others do not.




Nevertheless, He Persisted ...



Clearly I'm somewhat chomping at the bit to weigh in on some things I picked up on from the totality of the three hours of podcast.   But ... I really do want to address one focused topic at a time.  

To that end, I'll sum this post up, but not without some commentary on Gary Taubes' behavior during the podcast.  Related to just this 10-20 calorie per day issue, 

  • In my opinion it is downright dishonest for Taubes to even put forth this "measurement error" level of calories as a difference between the lean and obese.  
  • In GCBC, Taubes acknowledges the American obesity epidemic coinciding with a 300-500 calorie per day increase in average intake (depending on if reported or food supply is used as the measure), yet he concludes (#5 on his list) "Obesity is a disorder of excess fat accumulation, not overeating, and not sedentary behavior."
  • Guyenet corrects Taubes multiple times, on two points:
    • The obese consume 20-35% (and I would add even more in severe cases like Friend) more than their lean counterparts, and 
    • (more importantly) the 10-20 cal/day surplus is the incorrect way to look at how obesity develops and is sustained.
  • Despite being corrected, Taubes continues to bring up and express a desire to "get back to" this 10-20 calorie per day number as if this is correct and relevant.
Taubes has now been researching and writing on this stuff for closing in on 20 years.  He has had a long "relationship" with Kevin Hall, including "hiring" him to lead one of his prized NuSI studies.  As such, it is INEXCUSABLE that Taubes even mentions the 10-20 calories per day, let alone continues to bang that drum after being set straight.  He HAS to have read/listened to the counter arguments such as put forth in this post ... countless times!  The exact numbers may be flexible and influenced by individual characteristics, but the basic concepts are simply not debatable.
Who cares why we gain some fat free mass along with fat mass.  Common sense says we have to.  You don't even need to "do science" to figure out why.  And common sense dictates that we will expend more energy to move around that larger body, even if we argue over the best way to predict how much.

So in the end, over a decade after GCBC came out, it's rather unconscionable that Taubes is STILL around pushing his "alternative hypothesis" at all.  It never did explain the obesity epidemic, or the hows & whys  of even one single person getting fat.  So much of what was put forth in that book has been debunked to the point that he should be embarrassed by the majority of its content. 

Nevertheless, he persists.  Dishonestly.

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