Mighty Metabolism Mouse?

Thanks to Amber for bringing the following study to my attention: A high-fat, ketogenic diet induces a unique metabolic state in mice.   Does it appear that MightyMeta Mouse is on his way??  Perhaps ...  for mice anyway.  The KD fed mice attained the same reduced body mass as the calorie restricted (to 66% ad libitum of control chow fed) mice.  A fourth group were fed the usual high fat + sucrose diet to induce obesity.  Anthony Colpo ... pay up!?*

Animals fed ketogenic diet ate the same number of calories as animals that were fed either chow or a high-fat diet but nevertheless failed to gain weight. Remarkably, animals eating ketogenic diet lost a small amount of weight and achieved the same weight and body composition as animals that were calorie restricted to 66% of usual daily intake. Fat mass, lean body mass, levels of leptin, and glucose were the same in ketogenic diet-fed and calorie-restricted animals.
... KD fed mice had a unique metabolic and physiological profile, exhibiting increased energy expenditure and very low respiratory quotient.  Insulin levels were somewhat reduced in calorie-restricted animals compared with the chow-fed group, whereas insulin levels in ketogenic diet-fed animals were dramatically lower to a level that was only 10% of that seen in the calorie-restricted group.
Here are the intake, weights and body heat production for the mice:

The study began with 8 week old mice.  Mice are usually weaned at 3-4 weeks, so they had all apparently been eating a standard chow diet for approximately 4 weeks at the start of the study.  The first protocol (results above)  maintained them on the assigned diet for 60 days (just over 8 weeks).  They did some testing of the animals movement, etc. and determined that the well-being of the KD mice seemed to be quite good.  
These differences were highlighted by analysis of distinct metabolic pathways. In ketogenic diet animals, fatty acid oxidation and ketogenic pathways were increased, as may be expected. However, UCP2 was also increased sixfold compared with the other diets. This may have been a response to increased availability of fatty acids and increased mitochondrial fatty acid oxidation. The uncoupling and associated changes in metabolic efficiency may underlie some of the changes in energy expenditure seen in these animals.  Furthermore, fatty acid synthesis, cholesterol synthesis, and glucose-handling pathways were reduced in ketogenic diet-fed animals. Additionally, critical enzymes of gluconeogenesis, PEPCK, and G-6-Pase were suppressed, consistent with the reliance of these animals on ketones and fatty acids as energy substrates.
OK ... this change in efficiency is towards the inefficient metabolism.   It sounds like use of ketones for energy is less efficient rather than more efficient than using glucose for fuel.   
KD-fed animals had 11% higher energy expenditure than C-fed animals and 15% higher energy expenditure compared with the CR group
So, ketogenic fed animals had just over 10% higher energy expenditure vs. control chow fed animals.  If we're going to extrapolate this to humans, this would mean that if someone maintains on 2000 cal/day, and adopts an extreme ketogenic diet** they can eat roughly 200 cal/day more and maintain, or will lose some weight on KD eating at the same caloric level.  Looking at the KD v. CR, if a person fails to lose weight on 1000/1500 cal/day (as we're told repeatedly for women/men before the magical low carb mystery tour) calorie restriction, then apparently that is the person's TDEE.  Even old MightyMeta Mouse(Wo)Man, then, would burn 1150/1725 cal/day on a KD and maintain weight, or lose weight at a paultry rate of 0.3/0.45 pounds per week.

These energy differences were determined at 5 weeks into the study = day 35.  I note that KD mice lost body weight initially then stabilized out -- perhaps 5g/27.5g , or described as a reduction to about 85% initial weight in the study.  The CR mice, however, initially lost considerably more weight -- estimate 7.5g/27.5g -- which is 50% more than the KD group and over 25% of their initial weight.  This would likely trigger the often seen reduction in metabolic rate, and explain the weight rebound for the CR group.  

Now, let's talk health and body composition here folks.  As I've blogged on previously (see, for example, here), in direct contrast to TWICHOO, low carbohydrate/ketogenic diets tend to favor the fuel partitioning to fat vs. lean tissue rather than the other way around.  

MightyMeta Mouse is in Rosedale Utopia!  After just 5 weeks of the diet, the mice have next to no insulin or leptin compared to standard chow and the high fat diet.  Note: "c" is significant difference vs. HF, "a" is significant difference vs. Chow.  What did this do to the lean mass?  It dropped considerably.  The fat mass values didn't differ in a statistically significant fashion for KD v. C, but I wonder how a % fat mass or fat/lean ratio would have panned out.  (I note that when one adds up the masses on DEXA and compares these to the average body weights reported on the graphs presented earlier, there's an inconsistency there).   In any case, the KD mice lost weight, but predominantly from lean mass, seemingly preserving the fat mass if not partitioning more to that route.  I wish they repeated the DEXA at 9 weeks, but they did repeat some measures above and assessed a few more things.  

Does anything jump out at you guys on this table?? Interestingly enough, the HF group's NEFA levels seem to normalize. But KD? Well, they are elevated compared to all other diets.  But that's not the most troubling thing that I see.  How about those liver triglycerides folks??  You know what that is?  That foie gras we're all making of our livers eating the SAD?  Well, MightyMeta Mouse is well on his way alright!  The KD mice have roughly 2.5X the liver fat accumulation of their body-weight equivalent CR counterparts.   Aaaaack!!   They also have roughly 35% more liver fat accumulated compared with the poor porkster mice eating the high-fat (with sucrose!!) diet who weigh in at over 50% greater body weight compared to our KD Mighty!   Despite like no insulin -- ketogenic nirvana! -- these mice are packing the triglycerides just fine in their livers!!   
Histological analysis of the livers showed increased lipid vesicles in both HF and KD animals, and PAS staining showed decreased glycogen deposition in KD animals vs. both HF- and C-fed groups (data not shown).
The KD group appears to "scavenge" what it can and store it as liver fat.  Yum!  Now here's an interesting observation.  The second protocol took HF fattened mice and put them on the HFKD diet which reversed their obesity.  Sounds good so far.  And all the parameters improved:  lower insulin, blood glucose, etc. etc.  Still sounding great.  And then:
Paradoxically, the increase in glucose tolerance and correction of lipid profiles occurred in the context of increased hepatic triglyceride content compared with both HF and C groups.
As Scooby would say ... Ruh Roh!   Why the liver stores triglycerides rather than repackaging them for export in VLDL is a bit of a mystery to me.  Perhaps it's the liver's way of maintaining a local supply of ketone precursors in the absence of maintaining local stores of glycogen normally used to maintain blood glucose levels.  
Surely this is just a benign or temporary effect?  Well, I linked to the PDF of the study in this post.  The PDF's for studies in this journal contain a cover page including studies that reference the article.  This title kinda jumped out at me:   Hepatic steatosis, inflammation, and ER stress in mice maintained long term on a very low-carbohydrate ketogenic diet  (sorry, abstract only at the moment). 
Longitudinal measurement of body composition, serum metabolites, and intrahepatic fat content, using in vivo magnetic resonance spectroscopy, reveals that mice fed the ketogenic diet over 12 wk remain lean, euglycemic, and hypoinsulinemic but accumulate hepatic lipid in a temporal pattern very distinct from animals fed the Western diet. Ketogenic diet-fed mice ultimately develop systemic glucose intolerance, hepatic endoplasmic reticulum stress, steatosis, cellular injury, and macrophage accumulation, but surprisingly insulin-induced hepatic Akt phosphorylation and whole-body insulin responsiveness are not impaired. Moreover, whereas hepatic Pparg mRNA abundance is augmented by both high-fat diets, each diet confers splice variant specificity. The distinctive nutrient milieu created by long-term administration of this low-carbohydrate, low-protein ketogenic diet in mice evokes unique signatures of nonalcoholic fatty liver disease and whole-body glucose homeostasis.
One wonders how the life expectancy of these mice would compare to chow fed.

Oh wait!  We are not mice.  Guess we shouldn't worry that the higher liver triglycerides were accompanied by lower circulating fasting trigs in these KD mice. Lower trigs are something lots of LC'ers like to boast about.  Perhaps fatty liver is something to worry about?  Gosh after reading this I hope I didn't trash my liver doing VLC for so long.  I'm guessing/hoping not b/c I ate lower fat higher protein than most do.  

*Anthony Colpo famously issued a challenge ($20K if memory serves) for anyone who could provide proof of a metabolic advantage in a controlled human metabolic ward study.  I'd say that these results -- a 10-15% difference at one timepoint in mice -- do not qualify.  In studies measuring metabolic rate comparing VLC to other plans, I've not seen a difference reported in humans.  AC, your money is safe!

**I would note that this diet is  5% protein, 93% fat, 2% carb.  Even the high fatties in the LC movement tend to eat more than the conventional 15% protein.  

Follow-up post:  Is MightyMeta Mouse Relevant to Real Humans?


Sanjeev said…
ooooo ... interesting ... lard & butter for the keto diet.

several somebodys will NOT be able to play the "it's all polyunsaturated vegetable oils" card

As an experimenter I might have used lots of polyunsaturates because they are mobilized more quickly (can be more ketogenic) than saturated fats
Sanjeev said…
nothing about mucus/mucins (or lack thereof) in the KD though ...
Sanjeev said…
This was one reason I suggested people play with the carbohydrate content in Hall's simulator: higher dietary carbs resulted in higher lean mass for equal calories.

The data Hall used to develop his model must have shown a similar effect in humans.

Addendum to a previous comment: I wonder if it will occur for even a fraction of a second to those who've written so many times about liver problems in keto dieted mice to re-evaluate their many, many statements (paraphrasing) "it wasn't the high fat per se ... it was the safflower (or rapeseed, or corn, or soy) oil". I doubt it ...
rodeo said…
The fatty liver could be due to choline deficiency. The paper states that the ketogenic diet was supplemented with vitamins and minerals but since choline isn't always grouped as a vitamin it's not certain that choline intake was adequate.

Muscle wasting might be a result of the very low protein, only 5% of total energy intake. This might account for some of the other abnormalities as well.

Or what do you people think?
CarbSane said…
Hi Rodeo, In the "Hepatic steatosis ..." study (I just got the full text and will probably blog on that separately), I was able to find detailed specs for the Keto & standard chow diets. Both list choline content (the keto diet has about and below the citation of the diets used it states "The ketogenic and Western diets are vitamin and mineral fortified to match the standard chow diet." This was the same KD used in the primary study.

No doubt the loss of lean mass is due to very low protein content. I'll probably blog about the applicability of this diet to diets people consume that they call ketogenic at some point as well. Suffice it to say even ZC'ers eating fattier meat choices/organs and all that probably get far more protein in their diets.
CarbSane said…
This comment has been removed by the author.
CarbSane said…
Above comment 3rd line omit (the keto diet has about and ...), it just says that below the listing of the diets used.
Thomas said…
@Evelyn-its good to see you taking it to Rosedale over at Mercola's site (he didn't last long did he)! Mercola also propagates some mighty deep bull@#$% as well-simply a nutritional scaremonger..er..salesman. Anyway, keep up the good work (I don't know how you get these articles out so fast) and have a happy Thanksgiving!
Galina L. said…
I never heard of fatty liver decease plaguing epileptic children (they have some problems, but not this one) or Inuits. Probably, we all should ask Peter to dissect his pet rat he feeds with lard when it dies . What are the symptoms of the fat liver you can distinguish without the help of biopsy or ultra-sound? May be the central body obesity, or something in a blood test?

It is a very positive development, that ketogenic diet became the subject of multiple research studies. I wonder, hou well mice replicate humans in the regard of fat metabolism. Anyway, they have to start with mice, chimpanzees are too expensive.

As a person on a VLC diet, I can report, that in time my stamina improve dramatically. At the beginning, I felt running completely out of fuel in 45 min of cardio, not now. During weekend me and my husband went to a park which if the covered with asphalt former railroad in wooded area, he was bicycling and me rollerblading for 2 hours. I even didn't get tired, it was amazing. It is difficult to believe that condition that makes you feel much better mentally and physically is detrimental for your health.
Amber O'Hearn said…
Thank you for taking a better look at this than I had time for yesterday.

You didn't mention that the lean mass loss that happened in the KD was not significant in the limb measurement, only whole body measurement, and therefore they conclude it was not muscle mass that was lost. It was very likely water mass, don't you think?

"Whole body DEXA analysis also showed a decrease in total lean mass in KD-fed animals compared with both HF and C groups. To assess the possibility that the decrease in lean mass was secondary to muscle loss, DEXA analysis of the hind-limbs was performed. This revealed an increase in both fat and lean mass in the limbs of animals fed HF compared with both C-fed and KD-fed animals. There was no difference in either lean mass or fat mass between C-fed and KD animals"

I'm eager to respond to the rest of your points -- even if we disagree a lot, I consider it extremely valuable to have someone bring up challenges. It can be way too easy to miss things that contradict our own biases. However, I have company on the way, and must prioritize that for now.

I'm very curious about the liver triglycerides, and one point I'm pursuing is the butter content of the diet. High butter diets seem to have this effect in rats, compared to other fats: http://www.mendeley.com/research/lipid-and-fatty-acid-profiles-in-rats-consuming-different-highfat-ketogenic-diets/ , but I haven't had time to figure why, or if it matters.

Since ketogenic diets have been shown to *reverse* fatty liver disease, there must be more going on than it appears.
CarbSane said…
Hi Amber, I look forward to future discussions! We're hosting today too, so actually right after I post this I'm off to start some food. I will say that the amount of body weight being water seems awfully unlikely to me, so I'm thinking bone and organs perhaps, more thoughts later. On the next post some others have also raised the cases of reversal of fatty liver with keto diets. Off the top of my head I'm thinking (a) not as extreme keto as this diet, and (b) short term consuming less when going keto. Have a great day!
CarbSane said…
Hi Thomas, Thanks! & Hope you had a happy turkey day as well. I'm going to have to do a post listing all of Rosedale's erroneous statements. Sure seems every time we turn a corner in this debate, the old myths come roaring back. This postprandial insulin causing IR myth is a hard one to shake.

@Galina: One thing I note is that metabolically (e.g. blood lipids/glucose) the mice seem to fare well. It may be that they've never tested them for fatty liver. Long term followups are hard to find, but most do not stay on the diet very long. I wonder what the incidence of obesity, IR and/or diabetes is for adults who were on keto diets as kids.
Anonymous said…
Then there's this:
A high-fat, ketogenic diet causes hepatic insulin resistance in mice, despite increasing energy expenditure and preventing weight gain.
Jornayvaz FR, Jurczak MJ, Lee HY, Birkenfeld AL, Frederick DW, Zhang D, Zhang XM, Samuel VT, Shulman GI.
CarbSane said…
I'm getting more and more surprised I hadn't come across some mention of this before euler!
James Krieger said…
I'd like to note that this has already been looked at a number of times in humans and there is simply no evidence that a ketogenic diet elevates energy expenditure in humans. Only a high protein intake has been found to elevate energy expenditure by maybe 80-100 calories. Here I discuss one of the studies on humans:

Anonymous said…
One difference is that study done on rats allowed them access to food and water but did not control calorie intake. In the study discussed by James Krieger, calories were determined for 'energy balance' and controlled.

There are more differences - aside from the obvious, that one study is of rats and one of humans - but this one does seem important... if anything, giving greater weight to the study discussed by Krieger (which seems to focus on appetite).

Given uncontrolled access to food and water, the rats (whose food was a ketogenic 'mix') ate less food in terms of actual grams weight, yet ingested similar total calories. They ended up with more body fat from their diet.
CarbSane said…
Hi James, I think it's time to dust off my Mice v. Men posts in my draft hopper, tidy them up and publish. Because, as you say, many of the adaptations in mice have not been shown in humans. I think a huge part of that is the contribution of thermogenesis for small animals to the energy expenditure equation.

@euler: Over and over again it seems that the lower the carb the more the body partitions excesses or even what it's given into fat. Fattier, not fatter, but in the end we don't want either.