Saturday, December 31, 2011

Cake and cream

Serving suggestions for soured cream not really needed...

The ginger cake (in the last post) isn't really low carb but it helps keep the children (and me) out of ketosis! Nice diluted with butter.

Ginger and Banana Cake ingredients:

3 medium or 2 large bananas
100g total of macadamias, almonds, walnuts
100g ground almonds
2 eggs
100g brown sugar
100g butter
4 tbsp black treacle
1 tbsp ground ginger
1 tbsp baking powder
2 tbsp yoghurt
150g rice flour

Happy New Year


Monday, December 19, 2011


Danish butter is on offer in at least one UK supermarket, currently 10% less than economy butter. Surprise surprise. No better way to eat (gluten free, lowish carb) ginger cake:

Look at that bite. That's my catastrophic tooth organisation! That really is how my teeth developed as a youngster. Not much to be done about that nowadays...

On the baby front the carnivory continues:

And I've largely replaced creamy cocoa with chocolate butter:

One 100gm chocolate bar (85% or 90%), One 250gm block of economy butter, 45ml double cream, 15 or 30ml honey and some vanilla. Melt, pour in to an ice cube tray, freeze, pop out of tray while frozen, keep in fridge until consumed, not very long...

It partly settles out unless you are very careful with temperatures but tastes none the worse for that.

Reading wise it's still all mitochondria and there are a million things to check but it remains interesting in the extreme.

What with the children's birthdays, Solstice, Christmas etc there is not a lot of free time but I'll get some posts up sometime!

Happy mid Winter Festival time to all


Brings back memories of last year's Solstice, driving across the Acle marshes in to a brilliant dawn with a lunar eclipse in the rearview mirror. Lovely to live just above the adjoining marshes nowadays.

Monday, November 21, 2011

Adipotide and the Bad Fat

Just a brief respite from mitochondria:

Adipotide is a drug which targets the blood vessels supplying adipose tissue. It causes impressive fat loss by killing fat cells. Anon posted these two links on the last post.

There are other processes which can produce adipocyte destruction. We've discussed both acquired and congenital lipodystrophes in the past. They produce whole body fat loss with progressively deteriorating glucose tolerance because fatty acids have no adipocytes to enter, so end up accumulating in all tissues, producing pathological insulin resistance and diabetes. This is basic physiology and exactly what you would expect.

Adipotide is different. It produces fat loss with improving metabolic conditions and decreased hunger. How come a dead adipocyte is good from Adipotide and bad from auto immune attack?

Alex emailed me the full text. Here is the snippet from the email conversation which was my initial take on what might be happening:

"How does the drug get any improvement? You'd need to see the data and how they generated it but if the drug preferentially targets abdominal fat there would be an improvement in systemic insulin resistance until enough total [whole body] fat cells were lost for the overall for deterioration in insulin sensitivity due to muscle lipid accumulation to precipitate diabetes.

Of course during lipolysis you would have FFA release acting like an obese fat cell becoming insulin resistant and sending FFAs systemically to most non CNS mitochondria... Reduced need for food and increased ATP for activity from the metabolic flexibility perspective..."

Look here: Surgical removal of visceral fat improves peripheral insulin sensitivity (there's a lot I could write about this paper but no time). This paper looks OK, other papers by this group are very dubious.

Visceral fat seems quite important, here's an early brief review.

And here is the only quote we need from the Adipotide paper (thank you Alex for the full text):

"MRI and DEXA imaging confirmed that weight loss in the rhesus monkeys occurred primarily because of visceral fat loss."

Now, that's all hunky dory. What is the question we need to ask? Actually, there are a few:

Why is visceral fat Bad Fat? Why do we make it? If we get rid of the Bad Fat, will health be Good for ever? Did we evolve Bad Fat to kill ourselves? Is there a survival benefit from Bad Fat if we continue to drink >30% of our calories from fructose based drinks? Would having our omentum removed do good or bad things long term if we continue to mainline fructose? Would we need to get rid of our Bad Fat if we poured the Fanta down the urinal rather than down our throats?

I rather like Bad Fat. It opens all sorts of avenues of thought. There's so much about it that fits together but no more time to blog at the moment.


Thursday, November 10, 2011

LIRKO mice (3) The MCQ

**************EDIT - This is serious**************

It has been pointed out that this post is a deliberate intention to mislead. I would like to deny this categorically. The allegation is based around my personal error relating to the renal glycosuria threshold of rats. I have never treated a rat for diabetes. Apparently they do not become glycosuric until blood glucose exceeds around 400mg/dl, somewhat above the glycaemic level of LIRKO mice and waaaay above the cat, dog or human threshold.

They are still functionally diabetic, despite the lack of glycosuria, in terms of hyperglycaemia. But it appears that YOU CANNOT MAKE JAM from their urine.

I would really like to say I hope Dr Guyenet did not waste too much time trying to get his rather watery jam to set. But I just can't. I guess he spent a lot of hours.

Mea culpa.

Sorry to anyone other than Dr G who tried this. Better buy your jam ready made.

******************END EDIT******************
I see the LIRKO mouse has resurfaced as a destructor of the role of insulin in obesity yet again. I've posted on the LIRKO mouse in the past so this little quizz should be quite straight forward. I skipped the questions about leptin because I felt like it.

WARNING some of the questions may have more than one correct answer.

Q1. What is the blood glucose of a LIRKO mouse after a mouthfull of chow?
a. 400mg/dl
b. 400mg/dl
c. 400mg/dl
d. WTF, no one told me LIRKO mice are intensely diabetic.

Q2. What is the urine glucose concentration of a LIRKO mouse?
a. Some
b. Quite a lot
c. More than quite a lot
d. Obesity researchers boil it down to make jam.

Q3. The liver of a LIRKO mouse has no access to glucose. Where does it source it's energy?
a. Not from glucose
b. Definitely not from glucose
c. Absolutely, definitely not from glucose
d. Where's the fat?

Q4. How much fat is there in mouse diet F9?
a. Not a lot.
b. Not a lot
e. Not a lot
d. 10%, just about enough to run the liver on, rather badly, giving early onset cirrhosis and death.

Q5. How much de novo lipogenesis (DNL) from glucose is done in the liver of a LIRKO mouse?
a. None
b. Zero
c. Zilch
d. LIRKO mouse liver can't take up glucose for anything because it has no insulin receptors. Ha ha, gotcha, this is a trick question.

Q6. If the dietary fat is used to run the liver and there is no DNL, where does the fat in adipose tissue fat come from?
a. Thin air.
b. Spontaneous generation
c. Beamed in from The Enterprise
d. A small nuclear reactor
e. It doesn't, you can't put in what you haven't got. OK, there is a smidge of DNL in adipocytes.

Q7. If a LIRKO mouse at the gym is losing more calories down the urinals (where glucose is collected for making jam) than it burns on the treadmill, why doesn't it eat more?
a. Blood glucose is 400mg/dl
b. Blood insulin is 80ng/ml
c. Both.
d. Yeugh, is that really how they make jam?

Q8. The LIRKO mouse is hyperinsulinaemic. By how much does this lower plasma free fatty acids?
a. By 40%
b. By 40%
c. By 40%
d. By only 40% because adipocytes, like the rest of the mouse, are intensely insulin resistant.
e. WTF, no one told me they had depressed FFAs.

Q9. How would the LIRKO mouse cope with a saturated fat based, intensely ketogenic diet?
a. Well
b. Really well
c. Really, really well
d. Don't ask, don't even think about it.

Q10. Obesity researchers trot out the LIRKO mouse because:
a. They want to share
b. They want to share
c. They want to share
d. Shut up and eat your carbohydrate. You need insulin to get slim. Mmmm LIRKO jam...


Friday, November 04, 2011

Metabolic flexibility and the identical twins

This post is highly speculative. It doesn't have any answers. Here is a nice quote to begin with:

"If you want to retain your sanity, don't try to read a textbook on mitochondrial diseases"

This is from Nick Lane on page 281 of Power, Sex, Suicide. I was going to copy out the preceding paragraph but I guess everyone has their own copy of PSS. If not, you know what to do.

Now think about your sanity if you are dealing with a problem like obesity and you don't accept it's mitochondrial... Also think about the likelihood of successful intervention.

So I'm putting this up as a one-liner-which-grew because Liz dropped this paper me a few days ago and I got chance to open it today (OK, over a week ago!).

Enrol monozygotic twins in Finland. Hunt out BMI discordant identical twins (they are very rare) from the study, ie pairs of genetically identical people where one gets fat and one doesn't, despite their identical nuclear genes. Do lots of studies, get a Nature publication or ten out of it and decide obesity occurs because folks eat too much and move too little. Go to the top of the class as obesity researchers. There's a lot of it about.

Let's pick through the discussion and look at some of the conclusions from the metabolic flexibility point of view:

"a slightly higher birth weight (193 g) was observed for the twin that developed obesity during early adulthood, but this difference disappeared by age 6 months and the growth patterns of both twins were virtually identical until the age of 18 years, after which BMI differences between the co-twins became statistically significant (Figure 3)."

Pre-obese half of the pair of twins were heavier at birth, ie heavier in-utero. They must have been sneaking out to Macdonalds while telling their mother they were off to the gym. Amazing what some pregnant women will let their foetuses get up to. Next:

"After age 8, the pairs who later became discordant for obesity were heavier than the population mean, raising the possibility that genetic or environmental factors predisposing to obesity may be present in both co-twins of the discordant pairs. It therefore remains an open question as to whether the lean or the obese co-twin actually is more closely following the genetic predisposition."

Both twins have identical nuclear genes. These may or may not predispose to obesity, who knows? The obese twin has more defective mitochondrial genes than the one who remains slim. Each followed their need to produce adequate ATP. The one with worst mitochondria had to become obese to get there. Even the "slim" twin was heavier than average. His mitochondria might not have been so hot either, but not bad enough for serious malfunction. Next:

"The results suggested that physical inactivity in adolescence strongly predicted the risk for obesity (OR 3.9) and abdominal obesity (OR 4.8) at age 25, even after adjusting for baseline and current BMI."

Physical activity in adolescence is difficult if you have inadequate ATP production, so is minimised. At this age the affected twin is pre-obese. Obesity is necessary for elevation of FFAs to a level which will normalise ATP production to allow normal physical activity with sub normal mitochondria. Insulin will raise fat depots to an adequate size to elevate FFA supply due to adipocyte insulin resistance, once childhood growth has ended. Next:

"At age 25, the obese co-twins were only half as active compared with their lean co-twin as demonstrated in the 7-day accelerometer measurements.31 However, the total energy expenditure and activity-induced energy expenditure from the doubly labelled water did not differ between the co-twins. This discrepancy may be explained by the fact that the obese twins, while moving on average less, do expend more energy when they do because of their higher body weight."

THERE IS NO DIFFERENCE IN ACTIVITY OR CALORIE INTAKE BETWEEN TWINS ONCE OBESITY IS ESTABLISHED. An obese person moving from standing to sitting to standing again is doing a much weightier squat than the equally-idle-but-apparently-active skinny person with no fat to lift. Fatties may look idle because they don't get up from their chair if they don't have to but THERE IS NO DIFFERENCE in energy expenditure AT ALL compared to those equally "lazy" skinny twins who get up a few more times to burn the EXACTLY the same calories. OK, I've stopped shouting now. Doubly labelled water. Next:

"The basal metabolic rates (as measured by calorimetry) were considerably higher in the obese co-twins, presumably for the same reason."

Repeat shouting from previous paragraph. Plus, oops, they could have been talking about the Pima and forgot to mention that post prandial thermogenesis was depressed by almost exactly as much as BMR was increased.... Heard that before? I've not gone in to the logic of what is happening to BMR vs post prandial thermogenesis but it will undoubtedly come down to mitochondrial function. It just amused me that these established stars of obesity research were so familiar in their technique of citation. Next:

"The prospective Norfolk study of 20 000 men and women showed physical activity to attenuate the genetic predisposition to common obesity by 40%, as estimated by the number of risk alleles carried for 12 recently identified obesity predisposing loci.34 In the same study, the genetic risk score was positively associated with weight gain in inactive subjects, but negatively associated in physically active subjects."

No no no no. This appears to be saying that certain nuclear genes are associated with obesity if you are lazy. HOWEVER exactly the same genes are associated with you being THIN if you are active. I've not chased the EPIC paper because it's pure observational stuff but that's what this quote appears to claim EPIC is saying. Correct me if I am wrong. One explanation is that they are looking at the wrong set of genes. Obesity is a mitochondrial disease. It doesn't matter too much what your nuclear DNA says. You need good mitochondria to allow you to be physically active without needing you to be obese to improve ATP production. Duff mitochondria only allow you to be active if you have accumulated enough adipose tissue to trickle out FFAs. Next:

"However, the more objective measures via doubly labelled water revealed a substantial reporting bias by the obese co-twins: the under-reporting of energy intake (3.2±1.1 MJ per day) and over-reporting of physical activity (1.8±0.8 MJ per day) in the obese twins equalled to as much as one Big Mac hamburger, a 16-oz bottle of soft drink and almost 90 min of walking (3 m.p.h.), respectively. Interestingly, however, when asked to compare their own eating habits and physical activity to those of their co-twin, both co-twins openly reported that the obese co-twin had an unhealthier lifestyle with overeating, snacking and an irregular eating pattern as well as less physical exercise (Figure 4)."

This is a lovely paragraph. I think I have to accept from doubly labelled water that fatties lie about their caloric intake. This is very surprising. By doubly labelled water fattie twins do NOT eat any more than slim twins. They do not exercise less. Calories in and calories out are IDENTICAL in the obese and slim halves of the pair. Why should the fatties lie and claim to eat less than their skinny twin? Because they're fat...

I think it is also worth saying that the obesity-destined twin was noted, by all and sundry, to be "overeating, eating badly and eating irregularly" from an early age, with a preference for fatty foods. However I would comment that they did not even begin to become obese until 18 years of age and by 25 years of age doubly labelled water showed... etc etc etc. This moral failing as youngsters might just be translated as the pre-obese half of the pair were HUNGRY at that time. Life is hard when the world views your moral failings at the snack bar as evidence of your lack of will power. Being hungry is no fun. Being hungry because your adipocytes are not fat enough (yet) to ignore your hyperinsulinaemia and let you, grudgingly, have a few FFA molecules from their hoard is somewhat unfair. Your skinny twin is not hungry. He has mitochondrial ATP to spare. He sniggers at your third helping of pizza at your 18th birthday party because he has no gnawing hunger. He knows that you lie about how much you eat by your 25th birthday party. But by then he is eating EXACTLY the same as you are... At the gym, where he is well known, he only burns as many calories as you do walking up stairs. DOUBLY LABELLED water. Life is unfair. Next:

"Environmental influences independent from acquired obesity on liver fat were evaluated based on questionnaires and food diaries. Alcohol consumption from detailed questionnaires of the obese (3.7±0.9 doses per week) and non-obese (3.9±1.1 doses per week) co-twins did not differ and intra-pair differences in alcohol intake did not significantly correlate with differences in liver fat (r¼0.30, P¼0.14). Analysis of data from food diaries showed that the percentage of energy from fat (r¼0.37, P¼0.02) and saturated fat (r¼0.38, P¼0.005) did correlate with liver fat.5"

OMG it's the FAT (see end note), and it's the arterycloggingsaturatedfat (©Mary Eades) too. Phew. Fatty liver is due to (oops, I mean associated with) saturated fat intake. Not with Fanta. The ref for this is free to view. They, surprisingly, never did check the sucrose (or trans fat) intake against fatty liver. I don't suppose anyone thinks sugar has anything to do with fatty liver. Certainly it's not worth a line in the food breakdown table, even though it's probably just a click of the mouse away in the food analysis software... I seem to remember an obesity researcher pointing out that the obesity rise in the USA is associated with a fall in starch intake over 100 years and forgetting to mention the concurrent rise in sugar intake. There's a lot of it about. Excellence in obesity research, that is.

It gets better. The same group looked at fat preference. They really looked at fat preference. Not Fanta preference. They ONLY looked at fat preference. Perhaps there was no Fanta preference, it's not needed if the damage is already done. But the abstract gives no suggestion that they looked at anything other than fat... What answer did they set out to find? As I mentioned, there's a lot of it about.

Here's the scenario. Both twins get home from school. Pre-obese is hungry. Sneaks in to pantry and finds... Dadahhhh, a block of butter! You believe he skipped on the cookies sitting there?

Monozygotic twins have identical nuclear genes. They normally have very similar mitochondrial genes. But if there is mitochondrial heteroplasmy in the oocyst and one twin gets a bigger share of the decent mitochondria while the other gets a duff lot as they separate in-utero, things will be different. There will a discordance in BMI which develops in the attempt to normalise ATP production in the obese twin. The pre-obese twin is pre-obese in utero.

This would all be hunky dory if the mitochondrial heteroplasmy existed, with differing mitochondrial mutations between the twins. It doesn't, apparently. We find this snippet towards the end of the review paper:

"A novel finding of great interest in our obesity-discordant MZ pairs was the dramatic reduction of copies of mitochondrial DNA in the adipose tissue of the obese co-twin.12 Although the sequence of mitochondrial sequence was identical between the MZ twins (no evidence of heteroplasmy), the copy number of mitochondrial DNA in the obese co-twin’s adipose tissue was only 53% of that of the lean co-twin."

Sorry about the odd sentence in exactly the place where we want clarity, that's just how it is. Anyway, no evidence of heteroplasmy. But let's go and look up Ref 12.

This gives us this line:

"The mtDNA sequences of fat showed no evidence for heteroplasmy in co-twins, nor potentially obesity-associated sequence changes between obese and non-obese co-twins in fat or in leukocytes (Figure S1)."

I guess this might mean (as originally cited) that the sequences were identical between obese and normal twins, but it actually says there were no "potentially obesity-associated sequence changes between obese and non-obese co-twins", which may or may not be the same thing.

The next move is to another supplementary document which gives us this text (you don't have to read it if you don't want to):

"Analyses of mitochondrial sequence and copy-number

Known mitochondrial DNA sequence variants were extracted from MITOMAP database ( and variant information was annotated to the selected reference sequence AC000021.1 (GI:58615662) from GenBank. PCR primers were selected and re-optimized among those presented by Sigurdsson et al 7. Sequencing primers were designed to avoid known variant positions using The PCR Suite 8. The mitochondrial genome was PCR amplified in two overlapping ~9 kb fragments. PCR amplification was performed using 20-30 ng of DNA, 14 pmol each primer, 200 μM dNTP 1,4 U of DyNAzyme EXT DNA polymerase in 1X DyNAzyme EXT buffer (Finnzymes). Thermocycling consisted of denaturation of DNA template in 94ºC for 2 min followed by 30 cycles of 94ºC for 20s, 60ºC for 30s and of 72ºC for 4 min (extended for 10 s / cycle) and final extension of 72º for 15 min. Correct amplification was verified by agarose gel electrophoresis. PCR products were ExoI / SAP purified and sequencing was performed with BigDye3.1 chemistry on an ABI 3730xl DNA Analyzer. Mitochondrial consensus sequences and sequence variants were determined with SeqScape Software v2.5 (Applied Biosystems). Oligonucleotide sequences used in PCR and sequencing are presented in the Appendix of Supplementary Methods (vide infra)."

This is, to my rather limited experience, a standard PCR and sequencing protocol and is essentially guaranteed to produce mtDNA homoplasmy. Why? The number of abnormal mtDNA sequences is low amongst a huge number of normal copies. If you want to find heteroplasmy you have to individually sequence lots and lots and lots of mtDNA strands. Running a standard sequencing machine will not hack it.

The situation is clearly explained here. As they say:

"Here, we describe digital sequencing of mtDNA genomes using massively parallel sequencing-by-synthesis. Though the mtDNA of human cells is considered to be homogeneous, we found widespread heterogeneity (heteroplasmy) in the mtDNA of normal human cells. Moreover, the frequency of heteroplasmic variants among different tissues of the same individual varied considerably"

I've struggled with the methods to this paper and I'm not sure how many mtDNA strands they sampled from a given tissue. I think they might have done quite a few. This paper adopted a similar approach. Looking this hard you tend to find heteroplasmy if it is there.

It's there.

There are some interesting ideas in both papers about how heteroplasmy gets in to various tissues at various levels but they didn't go so far as to consider identical twins with mismatched phenotypes. A pity, because I think they know a great deal more about this than I do.

An obese twin has only 53% of the mtDNA of the slim one in their adipocytes. How about muscle cells? We know from the EMs of insulin resistant offspring of diabetic parents that their muscle mitochondria are grossly abnormal. We find from the twins study that lots of mtDNA (and presumably the mitochondria which might have originally contained it) simply isn't there.

It must be rather hard to find the mtDNA of mitochondria which are not there. Or mtDNA which is only there in very small copy numbers in the surviving mitochondria.

I personally doubt the mtDNA was homoplasmic in the obese twins. The unanswerable question is whether the heteroplasmy is responsible for the decreased mtDNA count...

There are a whole stack of ideas from the twins papers which need looking at from the mitochondrial selection pressure perspective, what controls mitochondrial number and how mitochondria control nuclear genes for their own synthesis...


BTW, compare these two abstracts, both from Finland Twins studies group:

Obese people love fat, always have done, 2002

Obese people now eat "avoiding fatty foods" while still indulging in "restrictive eating, frequent snacks, eating in the evening"... Same group 2007. Not snacking on blocks of butter after all then!

Both obese twins are considered, by these researchers, to have identical homoplasmic mtDNA in 2011. When will they change their minds on this? Soon I hope.

Wednesday, October 12, 2011

The Adipostat balloon

Right, back to links from Mary Rogge's paper on the role of impaired mitochondrial fatty acid oxidation in the obese.

She links to Ruderman's mini review, which we will come back to in some detail in future, and there we find this excellent graph:

I rather like this graph, although it could theoretically be reduced to one line of text. The bit I like best about it is that you can play Pin the Donkey Tail on it. We'll play later.

The graph shows that lipid oxidation, as indicated by respiratory quotient, is well below normal in both pre-obese and post-obese people.

But not in the obese.

No, the RQ of an obese person is, from the graph, somewhere around 0.825, ie an obese person actually runs their whole body metabolism slightly more using fat vs carbohydrate than a non obese person, who has their RQ at around 8.5 when on a mixed diet.

It is only the pre-obese or post-obese who run their metabolism on carbohydrate (poorly) and fail to oxidise fat, their RQ panning out up at 0.875.

If we ignore causes of mitochondrial dysfunction for the time being, we can look at these situations logically. I'm loathe to use analogies but they are useful on occasions. Here's one, highly factual and probably quite relevant:

Take a type 1 diabetic with complete failure to produce any pancreatic insulin. Ask them to volunteer to skip their exogenous insulin, become both profoundly hypoinsulinaemic and markedly hyperglycaemic. Then use a tracer to measure their glucose metabolism. Can they use glucose? Of course they can. This was done back in 1978 and the results are quite clear cut. Acute hypoinsulinaemia can be compensated for by acute hyperglycaemia.

Now, the question is whether there is a situation existing at the mitochondrial surface, as relates to fatty acids, which is analogous to that at the cell membrane surface as regards glucose. Glucose uptake is controlled at the cell surface. Fatty acid uptake is (predominantly) controlled at the mitochondrial surface.

Can we increase intracellular free fatty acid derivatives to the point where energy production can be forced back up to a semblance of normality in the abnormal mitochondria of a pre-obese person?

The graph of RQs suggests to me that this can indeed be done.

However it requires an increase in FFA delivery to the tissues well in excess of what a normal person might oxidise. There needs to be enough of an increase in FFA delivery to the tissues to reach the point where FFA derivatives can be "pushed" down an adequate concentration gradient in to mitochondria to restore adequate ATP production.

The cost of this maneuver is in increased FFA intermediary-derived insulin resistance and even greater failure to use glucose.

If you are having even more problems using glucose because you have managed to get your fat oxidation up by increased lipid derivatives within the cytosol, where would you expect your RQ to be compared to someone who has free choice in metabolic substrate utilisation? More fat, less glucose. So the RQ will be.....

Lower of course. Somewhere around 0.825 I would guess, looking at the graph.

You can see why I like this graph...

So we know that the pre-obese and post-obese have problems burning fatty acids in their mitochondria. We know the currently-obese have corrected this defect by increasing fatty acid delivery to their mitochondria at the cost of worsening insulin resistance.

How do we increase fatty acid delivery to the cytosol? Fatty acid delivery is primarily controlled at the adipocyte level. Insulin, acting on normal adipocytes, inhibits lipolysis. Have I ever said that before?

Adipocyte insulin resistance is the direct equivalent of relative hypoinsulinaemia. If we simply stretch our adipocytes to the point where they no longer listen adequately to insulin we can increase FFAs delivery to the blood stream and so increase their delivery to cytosol and get to work pushing them in to whatever mitochondria we have.

In the state of established obesity energy production is, in fact, normalised.

Let's just set this out:

Mitochondrial dysfunction leads to cytosolic fatty acid derivative accumulation.
This leads to chronic hyperinsulinaemia via insulin resistance.
This leads to adipocyte distension.
This leads to adipocyte insulin resistance.
This leads to increased plasma FFA delivery at a given level of insulin.
This leads to increased cytosolic FFA derivatives.
This leads to mitochondrial ATP production being normalised.

The cost is increased insulin resistance. Oh, and the MECHANISM for improved ATP production is OBESITY. Call this a cost if you wish.

BTW: Of course there is a second set of discussions related to adipocyte mitochondrial dysfunction but I'll leave that out to keep it simple here.


Time to play Pin the Donkey Tail.

Everybody needs a drawing pin (thumb tack?). And a piece of string attached to it to represent the donkey's tail. It is traditional to have a picture of a tail-less donkey taped to a cork board and to try and pin the tail in the correct place, while blindfolded. I'll let everyone off of the blindfold and we can have this nice blue balloon as a substitute for the picture of the tail-less donkey.

It would be very helpful, if you are doing this at home, to write "Adipostat Hypothesis" on the balloon, most easily done before you inflate it. I couldn't be *rsed to do this, as always.

Now pin the tail, using the thumb tack, on to the balloon.


Oops. Did you just pop the set point hypothesis of obesity? Clumsy of you, but easily done.

Obesity is a method of normalising ATP production. The concept of an adipose tissue "set point" is an artefact of how much adipocyte distension-induced insulin resistance is needed to normalise tissue ATP production at a given level of mitochondrial dysfunction.

Confession time. I never meant anyone to pop a real balloon. You don't have to actually do it. What I really wanted everyone to do was to pin a hypothetical donkey tail to the graph at the top of the post.

You need to guess what the respiratory quotient is for a person who, for the last seven days, has been eating a diet which included less that 20 grams per day of carbohydrate, around 60 grams of protein and as much butter as they like.

All you have to oxidise outside of your brain is fat. Your RQ will plummet to the lowest value possible short of full starvation. FFA delivery to non neural tissue will rocket. Glucose delivery will be irrelevant and the role of insulin in energy production will be sidelined. Cytosolic FFA derivatives will sky rocket too, to keep you alive using physiological insulin resistance, dontcha-no.

Perhaps you will normalise your ATP production?

Might you normalise your appetite too as you normalise your ATP production? It happens for many who try it...


I think ATP, AMP and AMPK might be an interesting subject to move on to next.

Thursday, October 06, 2011

Adipocyte insulin resistance

It was in late 2007 that I first blogged about the concept of adipocyte insulin resistance and of course it is back in my mind while I work through ideas on metabolic flexibility and insulin resistance in general. It is a very simple concept that the fatter adipocytes become (using whatever delivery system you like, ASP if you must) the harder it becomes to push more fat in to them. And certainly the harder it becomes to keep it there once it is installed. So this idea of adipocyte insulin resistance limiting fat gain is very intuitive and probably correct. How big adipocytes can get is probably determined by how strong your pancreas is combined with how responsive your adipocytes are to insulin as they swell. A pancreas of steel and relatively insulin-resistance resistant (no typo) adipocytes combine to get you to the over 200kg mark. This came up in comments on the last post. Is this true?

A rather nice paper was published back in the 1960s showing this very clearly. I have seen it cited as purporting to show that elevated fasting insulin is a consequence of obesity, rather than a cause. This is a fascinating and rather counter intuitive concept, so you just have to go have a look see at the paper. Luckily it's free access.

It does show, very convincingly, that adipocyte size correlates with adipocyte insulin resistance on the adipocyte cellular level. I rather like that.

It also demonstrates quite clearly that forced, brutal adipocyte size reduction by a couple of months on a 600kcal/d diet improves adipocyte insulin sensitivity as adipocyte size shrinks.

There are two core concepts which need to be taken away from this paper.

The first is that as adipocytes swell they become progressively less able to respond to insulin. This obviously translates in to insulin resistance of adipocytes ultimately limiting fat gain within the limits of the pancreas to secrete or hypersecrete insulin. That is if you accept that insulin is in any way involved in fat storage.

Now. What does this mean for the carbohydrate hypothesis of fat gain?

It is the RESISTANCE of adipocytes to insulin which limits fat gain.

And the corollary is??? Sensitivity to insulin drives fat gain. You can't have one conclusion without the other.

Anyone telling you that adipocyte insulin resistance limits fat gain and yet insulin per se has nothing to do with fat gain... Well, you decide. I have.

Although the group measured many, many things the only information we get about fasting insulin levels and post challenge insulin levels are these five paired graphs:

There is nothing in the text or tables giving any numeric data about insulin levels in obese individuals and no details at all from the normal groups. I don't mind this too much as the study was really aimed at adipocyte size and adipocyte glucose metabolism in response to exogenous insulin. This was the main drive of the paper. Note that they didn't look at adipocyte beta oxidation, no one had any idea this might be compromised back in the 1960s, so we get no idea about the ability of adipocytes to carry out this essential function.

Look, fasting insulin in five obese people is not generally elevated, it's reported as being only slightly elevated in two out of the five obese patients. This obviously implies that elevated fasting insulin does not predict weight gain. There we go. Time to pack up and go home.

Ah yes, but which fasting insulin are we looking at? Remember that group of starved obese folk we chatted about previously who had three different fasting insulin levels? One level on their normal (obesogenic) diet, one on a calorie and carbohydrate limited diet and another on the full starvation non-diet (ie complete carbohydrate restriction): 45 or 38 or 15-20 microIU/ml.

In obese people (but not in people who have normal metabolic flexibility) you can simply dial fasting insulin by carbohydrate intake. The question we cannot answer from Hirsch's study is what the fasting (and the 24h AUC) insulin values were for the five obese participants while they were free living on their normal obesogenic (high carbohydrate, you can bet) diet and slowly gaining weight? Remember we only need an average of 5g/d adipose tissue accumulation for long term obesity.

We are given an insulin value during phase I on a weight stability diet with a carbohydrate intake fixed at 45% of not-quite-enough-for-comfort calories. This is not what a given individual would normally choose to eat. In real life these people would not be on a weight stable diet. They certainly would not have been limiting their carbohydrate to 45% of calories. So we have no idea what their fasting insulin level would have been before stabilisation on phase I, but is certainly going to have been higher than the graphs show.

After massive weight loss during phase II of the study (on 600kcal/d for several months, probably only bearable because carbohydrate was limited to around 50-55g/d and the doors were locked [jk!]) we go in to phase III and get our second set of curves. Here we are now maintaining weight stability at a markedly reduced body weight with a smaller portion size of a still 45% carbohydrate diet, so total carbohydrate intake will be a bit lower. Hence the slightly reduced fasting insulin... But of course none of this represents the life which led to the enrolment in the study.

Subjects will be hungry.

While ever they stay hungry and limit carbohydrate to 45% of their never-quite-enough calorie intake, their insulin levels will stay low and they will, hungrily, stay slim.

Four of the five patients managed this for quite some time. Kudos to them and their willpower. You have to wonder about the fifth patient. Lost to follow up? Not lost to follow up but fatter than pre study? Just got fed up with people sticking needles in their butt?

How effective for long term weight control is chronic caloric restriction? Answers on a postage stamp to...

Are these people fixed? Their adipocytes certainly have scope to respond better to insulin and will inhibit lipolysis more effectively than during obesity. This limits FFA leakage due to insulin resistance which decreases FFA delivery to muscles and so allows muscles to take up glucose better, so both glucose and insulin curves improve. But are they really, really fixed? Will they will simply regain their lost weight, unless they enjoy being hungry all the time? Especially if they increase their total carbohydrate intake? And why are they hungry? Another post in this series there.

Addendum: Running through the methods section of Petersen's paper it is actually worth noting that fasting insulin and simple derivatives of fasting insulin plus glucose, such as the HOMA score, are rather blunt instruments for picking up insulin resistance. The more complex insulin sensitivity index is better but even this failed to pick out two out of twelve apparently insulin sensitive participants who turned out to be insulin resistant on the hyperinsulinaemic clamp, the current gold standard for picking out insulin resistant subjects. So, while insulin resistance is core, simple fasting insulin has to be accepted as a blunt instrument. Clamps, unfortunately, are not simple to perform. End addendum.

Of course you cannot dial fasting insulin by carbohydrate intake in normal individuals. So all you have to do is include enough normal people in your longditudinal studies and there will be no significant correlation between fasting insulin and subsequent weight gain. What would you expect?

Anyhoo, back to adipocyte insulin resistance. Stretching adipocytes appears to have effects on their sensitivity to insulin. As adipocytes stretch this translates in to progressive pathology as the adipocytes are running out of their ability to function normally. As they get fatter they leak more FFAs at a given level of insulin. This is important. Very important.

Before we go on to the next post: Is there any other form of adipocyte insulin resistance, other than that due to fat distension?

I rather like physiological insulin resistance. It keeps me alive. Simple carbohydrate restriction or a couple of days of frank starvation produces whole body insulin resistance to spare glucose for brain use. You know what I mean. Take a young fit healthy human and starve him for three days and he will immediately become intensely insulin resistant on a whole body basis. If not he would become intensely dead. Are adipocytes part of this physiological insulin resistance response, in the same way as muscle cells are?

We get a partial answer to this when Hirsch cites Tucker's study and suggests that the reason she found no difference between the adipocytes of obese and slim rats was because both were maximally insulin resistant after a 20 hour fast, even those from skinny rats...

"However, these studies were performed upon tissue from animals fasted for 20 hr, a manipulation known to decrease the insulin response of adipose tissue in vitro."

Ad hoc number 3523, but highly plausible. Every body knows this... Physiological insulin resistance mimics pathological insulin resistance. The mechanism through FFAs is likely to be the same.

This would again be logical as you do not want rats in starvation hanging on to their adipocyte energy stores or to be allowing precious glucose in to adipocytes (however little glucose adipocytes use) and so allowing it to be "wasted" when needed by the brain.

Is there a third factor affecting adipocyte insulin sensitivity?

Well, of course adipocytes have mitochondria. Are they breakable? Probably.

If you break them I would assume that they behave much like those in muscle tissue and they do the best they can with pyruvate while leaving the FFA derivatives in the cytosol, ie adipocytes should become insulin resistant if they have broken mitochondria. But this insulin resistance is not stretch related and it's not physiological. It's a mitochondrial break and could happen at any stage of distension of adipocytes. So mitochondrial failure should lead to adipocytes leaking FFAs when glucose and insulin are elevated. Possibly at minimal distension size, ie while you are still slim.

This would worsen whatever state of insulin resistance the muscles were in from their own mitochondrial problems. If the pancreas is not up to overcoming the supplementary FFA-induced insulin resistance (due to its own mitochondrial problems as suggested by Petersen et al) then hyperglycaemia will result and you get that label of T2DM... Possibly while still slim.

The plateau in your weight here might be mistakenly attributed to the satiating effects of insulin on your brain finally kicking in, somewhat belatedly, after 50 years or so of hunger.

If you have an unbroken pancreas of steel you can still argue with the broken adipocyte mitochondria and you can still get even fatter. Ditto if you have T2DM due to insulin resistance and some joker gives you a bottle of injectable insulin plus some syringes. Especially if they also tell you to eat a ton of bagels and cover the hyperglycaemia with a ton of exogenous insulin. And chide you for overeating.


Summary: Adipocytes become fatter under the influence of insulin. Resistance to insulin by adipocytes limits fat storage and hence eventually limits weight gain. It also elevates FFA supply. Important.

Tuesday, October 04, 2011

Denmark purchased using Flora profits?

Ali prompted me to put up this link and I see Barry Groves has something up about it too.

I think it was Iain Banks who wrote about corporate interests or massive personal wealth buying up a small country in the Himalayas, can't remember which novel it was. Fiction anyway.

Unilever appears to have bought Denmark. Where next for corporate take over? Hint, probably the UK, we're dumb enough. Probably not Hungary. At least the worst aspects of the Hungarian tax can be corrected with the shake of a salt cellar.


Saturday, October 01, 2011

HOW MANY bananas a day?

Our daughter eats everything. Her ultimate favourite food so far is a purée of pig heart casseroled in red wine. We tried her on a banana, head to head with 90% cocoa chocolate. My wife filmed the encounter.

The vocals at 19 seconds from the start sum it up.

Help was needed with the chocolate as it glues itself down to the tray, especially when well sucked!


Friday, September 30, 2011

Insulin resistant and slim. How slim?

This Figure 4 from the paper by Shulman's group on mitchondrial dysfunction in the offspring of T2DM parents, the one the EMs came from in the last post. It gives a nice outline of the way they are thinking:

and this is a summary of some of the points which came up in the comments (there is a lot of information and links from the comments about possible causes and management for those interested) added to the figure:

While I was raiding this paper I thought I would also put up Table 1, the characteristics of the control and diabetic offspring groups:

Now you have to be very, very careful with these groups. They have been exceedingly carefully preselected. Fortunately the pre selection process is laid out in some detail in a previous paper from 2004:

"All subjects were recruited by means of local advertising over a two-year period (2001 to 2003) and were prescreened to confirm that they were in excellent health, lean, nonsmoking, and taking no medications. A birth weight above 2.3 kg (5 lb) and a sedentary lifestyle, as defined by an activity index questionnaire,(21) were also required. Qualifying subjects (more than 150 persons) underwent a three-hour oral glucose-tolerance test (with a 75-g oral glucose load), after which two subgroups of subjects were consecutively selected to identify extreme phenotypes for insulin resistance and increased insulin sensitivity.

Insulin-resistant subjects (3 men and 11 women) were defined as having an insulin sensitivity index (22) of less than 4.0 (indicating insulin resistance; lower values indicate greater insulin resistance), at least one parent or grandparent with type 2 diabetes, and at least one other family member with type 2 diabetes. Insulin-sensitive control subjects (five men and seven women) were defined by an insulin sensitivity index of greater than 6.3 (with or without a family history of type 2 diabetes)."

As I read this it looks like over 150 people were screened for insulin resistance. Of those 150 those with the best and worst insulin sensitivity were selected as controls or subjects respectively. BUT you were only allowed in to the insulin resistant group if you did have a relative with T2DM. We get no idea of how many people had awful ISI and no diabetic relatives, ie if there were any index cases who might represent the red scrible on the second picture. Maybe there were loads, maybe not. I can't find that information in the paper. So we have to be very careful, the T2DM-relatives aspects MIGHT be a complete red herring. The insulin resistance is not.

Soooooo, with that caveat in place, we can see that (completely observationally) the insulin resistant group had, by definition, elevated insulin (and poor ISI) and the control group didn't. The control group weighed 61kg, the insulin resistant group weighed 66kg. Hmmmm. Observational, cross sectional. Fascinating.

You could simply say that the insulin resistant group were only hyperisulinaemic BECAUSE they were 10% porkier than the svelt control group. Indeed, if you consider porkiness to be a result of simple overconsumption of calories, for whatever reason, this would have to be an effect, not a cause.

Shulman's group extend the concept of mitochondrial failure in muscles to a potentially related mitochondrial failure in beta cells during the discussion. That's an interesting idea. Let's go one further and think about mitochondrial failure in adipocytes... I know it's odd to think that adipocytes (or indeed their mitochondria) might have anything to do with obesity, but stranger ideas have been floated.


BTW they also mentioned genes which control mitochondrial biogenesis:

"In this regard it is of interest that a common Gly482Ser polymorphism of the peroxisome proliferator–activated receptor γ coactivator 1, a transcriptional regulator of genes responsible for mitochondrial biogenesis and fat oxidation, has been linked to an increased relative risk of type 2 diabetes in Danish populations as well as to altered lipid oxidation and insulin secretion in Pima Indians."

I just noticed that the alpha form of peroxisome proliferator–activated receptor γ coactivator 1 got an honourable mention back in one of the Fiaf posts on the control of host metabolism by the gut mircobiota...

Thursday, September 22, 2011

Did you over eat yourself in to obesity or T2DM?

I have read Mary Rogge's paper on the concept that impaired fatty acid oxidation leads to obesity. This post is not aimed as a criticism of her ideas but modifies them somewhat, simply by following references she cites in her text and maintaining an insulocentric viewpoint. Obviously the failure of beta oxidation is strongly challenged by the success of low carbohydrate dieting and supported by the success of (extremely) low fat dieting. Is it correct?

There are a fantastic number of pieces to the jigsaw puzzle of obesity in this paper, many of which are probably very important and I'll run through them as soon as I can get my head around which ones matter most.

The basic concept is that there are excessive fatty acid derivatives in the cytosol of muscle cells (and probably other tissues, the main thrust of the paper is toward muscle metabolism). Why I view this as supportive of the carbohydrate/insulin hypothesis of obesity is yet another post. This particular post is on some of the problems I have with the concept of a simple defect in fat metabolism as the cause of the accumulated fatty acid derivatives.

As so often there will be a series of stolen diagrams, scribbled over using Powerpoint, which probably break every copyright rule in the book... Oops. Here we go.

Okay, here is the basic concept as a straight copy-paste:

Uptake of long chain fatty acids in to the mitochondria is mediated through carnitine palmitoyltransferase 1 (CPT1, green box upper left hand side). This is suggested as the failed step.

But there are problems with the diagram. Look here:

Here we have citrate being exported from the mitochondria and converted to malonyl-CoA via "fatty acyl-CoA". I think it would have been much better to actually specify acetyl-CoA at this point rather than "fatty acyl-CoA", but that may be nit picking on my part. But it is ONLY acetyl-CoA which is liberated by the citrate shuttle. The function of the citrate shuttle is to get acetyl-CoA out of the mitochondria and in to the cytosol for fatty acid production...

Next we have this feature:

I'm not sure whether this arrow suggests that fatty acyl-CoA, straight from triglycerides, facilitates or activates the citrate shuttle (I can't find any suggestion of this being the case) or is being cited as a source of citrate, which it is not. For fatty acids to form citrate they have to under-go beta oxidation:

And this is not supposed to be happening because the malonyl-CoA is inhibiting CPT1 mediated transport of fatty acyl-CoA to the site of beta oxidation. Hmmmmm.

So where might the cytosolic malonyl-CoA be coming from? Is glucose supplying so much citrate that the obese can use it for malonyl-CoA production?

If we flick to this fascinating reference we can look at the TCA cycle itself, to see whether glucose is producing enough citrate to export for conversion to malonyl-CoA as the spanner in the works.

From the paper we can see that if you have a very complex magnetic resonance spectroscopy machine, which you are willing and able to home-modify (read the methods text!), some exceedingly complex computer models and a supply of carbon 13 labelled acetate tracer you can actually work out how active the TCA cycle is in normal vs insulin resistant muscle tissue. This paper is so cool.


The offspring of diabetic parents have crap TCA cycle activity in their muscle tissue. It will not be producing the amounts of citrate which might be exported for fatty acid synthesis. This is not a failure of beta oxidation. It is a failure of the TCA cycle in its entirety. The fact that obese people run their metabolism on glucose does not mean that they run it well on glucose.

Why is the TCA cycle so compromised?

This study has some excellent pointers. Look at this picture, it could be from an obese or diabetic individual:

These folks have odd muscle tissue.

a) They don't have many mitochondria, b) many of their mitochondria look crap and c) many of their mitochondria are dying.

They don't have a simple failure of fat oxidation, they have a failure of mitochondria full stop. It simply shows most clearly in the failure of beta oxidation.

I'll take a break now and put this post up. There are, of course, a whole stack of follow-ons to this. If you have duff mitochondria you accumulate fatty acid derivatives in your cytoplasm. They cause insulin resistance. Once you have insulin resistance you will be chronically hyperinsulinaemic and, in all probability, go on to develop obesity as a direct consequence of that hyperinsulinaemia. Let's make this plain. Mitochondrial dysfunction is present before obesity develops and does not revert to normal on forced weight loss.

Over eating is not causal. Whatever anyone tells you.

If you are an undamaged human being and you force overfeed yourself with FOOD, say in some tribal ritual, I would suggest that you will not do this to your mitochondria. You will continue to burn fat easily. You will not develop chronic hyperinsulinaemia. You will lose weight automatically after that cultural binge is, thankfully, finished and you can get back to life within your normal appetite.

Humans do such weird things to themselves! Culturally and accidentally.


Saturday, September 17, 2011

Back on line

Well that's me back from the AVA meeting in Liverpool. Highlights: Arterial blood gas sampling at the top of Everest, all rough quotes from memory:

"The peak was a bit 'peakier' that we had anticipated so we dropped down a few hundred feet to a more level patch before dropping out trousers in a 20 knot breeze at -24degC to stab each other's groins for arterial blood samples".

Getting to the top of Everest? "I never train" linked to "it's all mitochondrial" and "Ground level athletes really struggle on the big mountains, Ranulf Fiennes took three attempts to get to the top and it was very hard for him".

Reinhold Messner is STILL ALIVE (obviously he has remarkable mitochondria). OMG I thought he'd have made a single small mistake at some point before now. Having read some of his earlier achievements I'd never expected him to make old bones. But he must be older than me...

And the RN battlefield anaesthetist from Iraq/Afghanistan. "These guys come in needing one, two or even three amputations from an environmental temperature at up to 40 degC. One of the worst prognostic markers is hypothermia. We think it's mitochondrial".

A good friend (with an excellent brain, yes she has already read Power Sex and Suicide while moving from anaesthesia to obesity research) chatting about DMT2 in horses "It's all mitochondrial".

One of her co-workers on cartilage degeneration in arthritis "It's all mitochondrial".

I had a great meeting.

I got, without net access, to read through and analyse some of the implications of the downloaded papers on mitochondrial dysfunction in obesity from JS's page on metabolic flexibility. Needless to say these links are good but you HAVE to read the papers, follow the secondary links then read the methods. Needless to say there is a lot to say and I'm still not about to go carb loading.

Time to get the Baba-breakfast ready. I'll try to get to emails and read comments over the w/e, but life really is very busy.

Quote of the century: "It's all mitochondrial".

Oh, and it's not quite as simple as failure to burn fat.


Monday, September 12, 2011

A defect of fat metabolism and a few thanks

I have, in the past, been given a key piece of information, put it in my pocket and left it there.

This is unforgivable, I know. But if the key is important enough you will have to either go through you pockets or be given another copy.

I am grateful to the rather unpleasant episode with Stephan as it allowed someone to supply me with that replacement key.

Metabolic flexibility is a slight misnomer, it describes a defect in fat metabolism.

I thank Stephan for getting me off my arse.

I thank Nick Lane for Power Sex and Suicide.

I thank M. for getting me to mention metabolic flexibility in comments.

I deeply thank J Staton for doing all of the work for me, reading Hyperlipid and taking the trouble to get the key cut then posting it to me via the comments. Go read.

There is no need to re invent the wheel. After reading the yellow box warning you can read this perfect quote

"This is a long and detailed article, but it’s very important".

And from elsewhere, if the post hasn't been taken down:

"A defect in fat metabolism?" Cracking quote, that one.

This fits with so many things which have become very, very obvious to me over the years. Neatly, logically, tidily.

Thanks all

Peter, the shoe-horner with the inappropriate prefix.

Sunday, August 28, 2011

Should we abandon the carbohydrate hypothesis of obesity?

I have read Good Calories Bad Calories. At just under a kilogram there are minor points within it with which I disagree. But, for the majority of the people who have read it, it is basically correct.

One of the most recent critical appraisals of the carbohydrate hypothesis of obesity was posted by Stephan over at Whole Health Source. Obviously, I disagree with Stephan's appraisal. That's fine, to disagree is perfectly OK. We'd get nowhere if we all sang from the same hymn sheet. This post is basically my take on the evidence used to destroy the carbohydrate hypothesis. It's depressing to have to do this but reassuring at the same time.

So why do I cling to this apparently incorrect and outdated hypothesis? Let's look at the points in approximate order as taken by Stephan.

A defect of fat metabolism?

Taubes ignored leptin to concentrate on insulin; this appears to be the main conclusion in this section. Stephan cites a neat paper by Leibel et al which demonstrated that in four healthy, never-obese humans the fall in metabolic rate induced by 10% weight loss could be reversed by physiological leptin replacement. That's cool if you want to be a young, fit, healthy, never-obese experimental volunteer desperate to live comfortably at 10% below your normal, slim weight.

If you are currently morbidly obese it may be of some comfort to know that leptin might be able to help you correct your hypometabolism should you manage to lose some weight.

If you are ex-morbidly obese and have managed to lose a few hundred pounds of fat you will still own a set of injured adipocytes. These injured adipocytes refuse to produce physiologically appropriate levels of leptin for their fat stores. Now THERE is a role for leptin. It might even reverse the persistent hyperinsulinaemia present even during starvation in the morbidly obese...

If you are currently morbidly obese and think leptin will help you lose weight, think again.

So do I think leptin is unimportant? Of course not. Does this invalidate the carbohydrate hypothesis? Shrug.

What about the morbidly obese ob/ob mouse, which cannot make leptin? There are a handful of human families on the whole of the earth with this problem. They need leptin and it will work for them.

The population of the USA is around 300 million. Of the adults in this population, as of 2008, 34.2% are overweight, 33.8% are obese and 5.7% are morbidly obese. They are not going to benefit from leptin supplementation to lose weight.

According to Stephan many, if not most, of these few million people will benefit, for reasons which are not entirely clear, from carbohydrate restriction. But it's not due to lowered insulin levels... Fascinating conclusion.

How can anyone be so sure that it is not from a reduction in insulin levels?

Here's why, watch very carefully:

You may think you have seen this clip before but no, although the child is the same the chocolate is different. This is 90% cocoa chocolate, none of your boring 74% sugary stuff...

If your baby is going to self feed chocolate you are going have to bath her. Bathing babies is dangerous. We also have one of these:

I always try not to throw out the baby with the bathwater. You can't be too careful...

The big problem with insulin, as any obesity researcher will tell you, is that it is a satiety hormone. I've said it before, all you have to do is have it injected in to your brain and you won't feel like eating a steak for the next few hours. Let's get a nice juicy quote from this paper by Velloso and Schwartz, hot off the press in 2011:

"A major and persisting source of confusion surrounding the hypothesis that insulin action in the brain reduces food intake and body weight while also lowering hepatic glucose production and increasing thermogenesis stems from evidence that following systemic insulin administration, the subsequent fall in glucose levels potently increases food intake while also increasing liver glucose production and reducing sympathetically driven thermogenesis. Thus, insulin-induced hypoglycemia potently overrides virtually all of insulin’s central effects, an observation that for many years has confounded research in this field."

Did you see the baby go? Here it is again:

"Thus, insulin-induced hypoglycemia potently overrides virtually all of insulin’s central effects".

That's it: Baby, bathwater, gone. How can anyone be so careless? Oh, did you miss it?

The baby is the peripheral effect of insulin on lipolysis, which is discarded without mention. Because hypoglycaemia in your brain (a central effect) makes you hungry, the fact that hypoglycaemia can steamroller insulin's central effects appears to have allowed the discard of insulin's peripheral adipocyte effects. Insulin's inhibition of lipolysis, in a normal human being, occurs at concentrations which do not even budge muscle glucose uptake. Infuse it directly in to the arterial supply to the fore arm and the systemic hypoglycaemic effect is lost. All you get at low infusion rates is inhibited lipolysis. This is the baby in the bathwater. Up the rate a bit and potassium uptake is increased. Bugger glucose uptake, this needs far more insulin that inhibition of lipolysis or promotion of potassium translocation. To summarise, if abnormally high insulin levels are needed to deal with unwanted hyperglycaemia then lipolysis will be inhibited until such a time as fat cells become so distended they refuse to listen to this excessive insulin, ie when they have become insulin resistant.

There are certain other spectacularly obvious problems with this accidental baby loss. Once we have all accepted that insulin is a satiety hormone it becomes perfectly obvious that people on low carbohydrate diets, with their chronically reduced insulin levels, should be hungry. After all, I have seen it suggested by Stephan that insulin might assist weight loss. I'm still trying to get my head around that one, while eating low carb and trying to remember what it felt like to be hungry. Trouble is it's all so many years ago... Of course, as Stephan points out, hypoglycaemia is a potent appetite stimulant. Again LC eaters, with their chronically low blood glucose levels, should be ravenous. I'm also trying to get my head round that one too. Reality occasionally gets in the way of great theories. Sigh.

I'm not quite sure where to put in the neuronal insulin receptor knock-out mouse. It's fat, so the conclusion appears to be that brain insulin receptors are important to satiety. I'm sure they are. However, these fat mice are also hyperinsulinaemic and will be lipolytically challenged. I love these particular KO-mice... They do not have me mainlining insulin as a weight loss drug. I love the impaired spermatogenesis and ovarian follicular maturation too. I still would not decry leptin here but these hyperleptinaemic mice don't do reproduction terribly well. Dare I use the I-word when talking about fertility?

Insulin inhibits lipolysis. Don't forget that when we come to talk about the Pima.

Before we move on let's look at the satiating effects of foods. Stephan's refs 4, 5, 6 and 7 suggest no macronutrient matters much and ref 8 shows protein is more satiating than carbohydrate. But reference number 9 is the absolute beauty.

Satiety is proportional to the insulin response to protein. Wow! Must be the anorexic effect of insulin.

But there are problems, wouldn't you guess. I don't have the insulin/glucose data following ingestion of any of the proteins mentioned in the abstract but let's look at the effect of casein, which I do have data for. The principle is identical.

Casein raises blood insulin level from 39pmol to over 100pmol and it's still at 90pmol by the three hour mark when sampling stopped.

Amen, RIP the insulin hypothesis.


But just a minute.... There is no sugar in casein, any more than there is sugar in beef. If we took these same seven volunteers and, without feeding them, injected them with enough exogenous insulin to raise blood level to 100pmol and peg it there while simultaneously locking the canteen door, they would die in hypoglycaemic seizures somewhere around the 10 minute mark. We could even throw in a little amylin (which obese people happen overproduce, odd that) to stop them being hungry as they die.

But elevating insulin to lethal levels using glucose-free casein, beef, whey, eggs etc all produce acute, severe, unremitting, paradoxical normoglycaemia.

I can't blame Stephan for not mentioning glucagon as it doesn't help destroy the carbohydrate hypothesis. Explaining the physiology seems to be my problem.

In healthy people eating neat protein there is a rise in glucagon which slightly under compensates for, as far as blood glucose is concerned, the rise in insulin. There is normally a slight fall in blood glucose.

Does glucagon increase lipolysis? It certainly does in pharmacological doses, as any physiology text will explain. In real life people seem rather unwilling to publish the data. You would have thought that 30 seconds on pubmed would have shelled out the effect of isolated protein on lipolysis but there you go, the insulin hypothesis, while defunct, discourages dabbling...

In this study they fed children consistent meals of mixed formula for a couple of weeks, then they switched them to a split meal protocol with most of the carbohydrate in the morning meal and all of the protein in the afternoon meal, fat being held constant for both meals.

The morning high carbohydrate meal suppressed FFAs as you would expect because insulin inhibits lipolysis. The afternoon meal of reduced carbohydrate, high protein content spiked insulin all right, but also increased FFAs. As dietary fat was held constant those FFAs almost certainly came from lipolysis. The group didn't measure glucagon but normoglycaeimia in the presence of insulin smells of glucagon to me.

Whenever someone does a hatchet job on the carbohydrate hypothesis using the insulinogenic index of beef without mentioning glucagon I am left wondering why they were carrying an axe in the first place. I find this thought very uncomfortable.

As a complete aside, people may enjoy this snippet on glucagon receptor deficient mice. You can eliminate the diabetic phenotype induced by massive streptozotocin overdose so long as glucagon cannot act. Interesting stuff but off topic really. But you cannot have death by lipolysis under hypoinsulinaemia without the lipolytic action of glucagon...

We next have two excellent studies correctly showing that resting energy expenditure is higher in both Pima Indians and schizophrenics in direct proportion to their hyperinsulinaemia. Oddly enough they don't simply melt away to size zero supermodels under the anorexic effect of insulin because their post prandial thermogenesis is depressed to almost exactly the same amount as REE is increased. Neat huh? Did you realise when you read the citation?

There comes a point at which fat cells become sufficiently insulin resistant that they cannot hang on to the their fat content. You can still put fat in there with minimal insulin and minimal insulin sensitivity. Once adipocytes are sufficiently insulin resistant and they are leaking sufficient free fatty acids to match input, obviously weight gain stops. The inappropriate spilling of FFAs causes palmitate deriviatives to be produced which worsen insulin resistance, whole body, and obesity flips in to diabetes.

I am in complete agreement with Stephan here. What I object to is citing a situation where insulin is failing to progress obesity, when it is doing its best to, as evidence it did not cause it in the first place. Insulin is trying and FAILING to make the adipocytes fatter. The more impossible the task, the more insulin is produced.

So we have a muscle cell, for example, which is wondering what the hell is going on as it sits in a sea of glucose and free fatty acids which is physiologically completely inappropriate. As we have been told by Stephan:

"Let me explain what the primary role of insulin is. It is to coordinate the metabolic shift between burning primarily fat, to burning primarily carbohydrate. Any time insulin suppresses fat oxidation, it increases carbohydrate oxidation by an equivalent amount. That is what it is designed to do."

In morbidly obese people, as they flip in to diabetes, this is EXACTLY what insulin is NOT doing. If you make fat cells more insulin sensitive (or generate some new, insulin-sensitive adipocytes), say with with PPAR alpha agonists, you will correct the elevated FFAs as insulin starts working on fat cells again and diabetes will abate slightly until the ability to store fat under the influence of chronic hyperinsulinaemia is once again lost, but at a higher fat mass.

I dunno, maybe PPAR gamma agonists simply increase food reward??????????????

Why is resting energy expenditure high in the obese? The body hates hyperglycaemia and wants to burn glucose whenever it's high. FFAs are a supply led system. Failure of adipocytes to respond to insulin increases supply. You then have excess glucose from the diet and excess FFAs from leaky adipocytes. You have to do something with the calories.

So does this destroy the "insulin locks fat away and decreases the metabolic rate of hyperinsulinaemic people" hypothesis? This has particular relevance to the multiple observations of utterly impoverished communities were adult obesity co exists with infant malnutrition. I would stress that this does not reflect the situation in the Pima community as studied in the 1990s, where childhood obesity has certainly been an issue and calorie malnutrition is not. Everyone has enough junk food to eat. Everyone can be obese, everyone can have enough calories to run a high REE, keep total caloric output down by decreased post prandial thermogenesis and still manage to gain a few grams of adipose tissue a day until diabetes sets in.

If there is enough obesogenic food for all, a mother will be hypermetabolic at rest and her kids will be fat. The insulin hypothesis predicts that if there is a restricted supply of hyperinsulinaemic food the mother will remain fat due to her hyperinsulinaemia, while the child will remain emaciated while ever she maintains some degree of insulin sensitivity.

Let's do reductio ad absurdum: Mother and daughter have 8000kcal of hyperinsulinaemia generating food available. Mother eats 4500kcal, becomes as fat as her adipocytes will allow her to, then she leaks FFAs from her adipocytes to become diabetic. Daughter eats 3500kcal and does the same. Both are hypermetabolic at rest, the mother more so as she is not growing. Both become obese.

Now lets say mother and daughter have 2000kcal between them. Mother eats 1100kcal, moves as little as she can, drops her metabolic rate, is hungry all the time but stays fat. Daughter eats 900kcal and is malnourished, becomes emaciated.

This is an aspect of the insulin hypothesis which has not been tested for obvious reasons. It will be correct, in my opinion. I am unaware of any evidence base for this.

As I understand the reward hypothesis, the mother and daughter eat a high reward diet, hit their dopamine system, desensitise it by over rewarding and this ups the hypothalamic fat set-point. Mother increases her calorie intake to maintain her set point level of fatness and eats her starving daughter's food to stay there. Fascinating.

The dietary practices of the Pima under severe calorie restriction are a complete unknown to me but I have serious problems with the reductio ad absurdum example I've just discussed. I've never met a mother who appears to behave that way, but maybe I've never met anyone with adipose depots far enough below their bodyfat set-point to behave this way...... Even folks on WeightWatchers seem mostly human.

So looking at modern Pima Indians or schizophrenics fed to satiety in no way tests the insulin hypothesis of restricted metabolism under conditions where insulin remains elevated and people are hungry. In fact Stephan's neat leptin reference suggests if we went in and injected the hungry, obese mother with leptin twice a day we would reverse her hypothyroid state, fire up a few uncoupling proteins and stop her being hungry. We might even drop her chronically elevated insulin levels. She would lose a ton of weight, give all of her food to her daughter and die of a starvation related illness herself. Injectable altruism...

Looking at multiple studies where adipocyte insulin resistance has occurred under ad libitum conditions certainly demonstrates how metabolism breaks under free access to insulogenic calories. I can't see how it refutes the role of insulin in obesity. It utterly destroys a straw man, but you have to actually do some thinking to understand what is going on.

It's all genetic:

Twenty monogenetic obesity syndromes! All in leptin signalling! Unfortunately a) That hasn't given us 20 solutions to help the 200 million overweight and obese people in the USA. and b) In the last 30 years fat people must have instigated a covert "fatties only" breeding program. Think of orgies where skinny people get castrated by fatties as part of BDSM games. We all know it's happening and there is a government cover up. From about the 1970s onwards.

Ultimately life is genetic and if there wasn't variation in response to insult there would be limited ability to select for surviving that insult.

If you want to REALLY look at what a blind alley the genetics of obesity are leading you up just try ref 35 from Stephan. Same genes in Mexican Pima and USA Pima. Only the USA Pima are fed on "D12451" and look like ob/ob mice. Mexican Pima eat Mexican food and blend in to the population. I looks like my BDSM hypothesis on generation of the obesity epidemic might be incorrect. Ah well, back to the drawing board.

Let's look at the natives:

Starch based diets are not associated with obesity. They do not cause hyperinsulinaemia, post prandial or fasting. They do not cause insulin resistance. You can, with significant effort, become obese on starch but only if you force yourself to do so.

I agree with this, in unacculturated people.

I think it might even have applied to people in the USA of 1900.

I disagree with this if applied to the current industrialised world, especially anyone who has become obese. Why should this be?

Obesity was present at a low level in the USA of the 1900s. Rumour, without hard data that I can locate, suggests it affected less than 1% of the population. It increased slowly until the 1970s by which time it was present in around 15% of the population. From 1970 to 2000 it doubled to 30%.

There's a graph on wiki here.

We know form Stephan's neat graph that this gradual rise in obesity between 1900 and 1970 was associated with a fall in carbohydrate consumption and that the rise in obesity after 1970 was associated with a rise in simple sugar consumption.

If you were to include a separate line to show sucrose (plus, as it became available, HFCS) it would rather neatly parallel the obesity curve. Obviously no one wishing to discredit Gary Taubes would do this but, if you are interested in hyperinsulinaemia as a cause rather than a consequence of obesity, I would suggest that you might be rather interested in this line. Once you are insulin resistant carbohydrates become spontaneously fattening. No ritual needed, it happens very much against your will.

The body uses fructose to replenish liver glycogen. There, I said it. The occasional bit of fruit will not make you obese. You only convert fructose in to a fatty liver through denovo lipogenesis when intake is in excess of what humans are remotely able to make use of. Elite athletes consume rather a lot of fructose. It helps them win races. Try breaking your leg by falling off your pushbike and then still keep up the cola consumption needed to keep you in the yellow jersey... You may just develop a fatty liver. OK, you will.

With a sucrose content in the diet averaging 64 lb/year very few people would start on that journey to hepatic denovo lipogenesis in the USA of 1900. At 120 lb/y over a third of the population will go that route. Once you have accepted that dietary fat causes obesity you are then going to eat the replacement carbohydrate which will dial up your fasting insulin and hunger. Official fat phobia kicked in during the 1970s...

Oops, I forgot that insulin is a satiety hormone and facilitates weight loss and a low insulin level will make you hungry. That good old low carbohydrate paradox.

There is a rather stupid saying that "you are what you eat". It is slightly better phrased as "you are what you do with what you eat". You could go so far as to say "You are what your food does to you". I won't go in to epigenetics except to say that you can think about the phrase "You are what the food eaten by your mother and granny did to you". Certainly to your X chromosome(s) and your mitochondria.

In 1900 very few people had grannies who consumed even 64 lb/year of sucrose. More likely less than 30 lb/year. I remember dipping white bread toast spread with margarine and marmalade in to tea sweetened with three heaped spoonfuls of sugar at my granny's house in Bargeddie on the outskirts of Glasgow. And being amazed at how she could actually bring herself to inject her own leg every day with insulin. This was back in the 1960s, I'd have been about 5 years old.

If you are overweight and try going on a starch based spontaneously hypocaloric diet you may as well sign up for Barndard's disastrous diabetes diet. If you are far enough in to metabolic syndrome to find the label "diabetic" has been applied to yourself, going to a high carbohydrate diet will ruin you blood glucose control as soon as you stop losing weight. No one can lose weight for ever.

I was going to say that no one is going back to Kitava from modern Texas but this clearly depends on how permanent the damage done to you metabolism is. The more damaged you are, the more carbohydrate restriction is likely to benefit you long term.

As I read through this post there are two things which come to mind. First is that elevated insulin is core to weight gain. Second is that we have to be very careful about exactly what, under which circumstances, elevates insulin. Discarding insulin as a factor in obesity because there are circumstances in which starch does nor invariably elevate insulin is a serious case of throwing the baby out with the bath water. There are circumstances in which carbohydrate does not elevate insulin. Most of us don't live there, we can tell by our waist lines.

This post has been a long time coming. I've not particularly enjoyed writing it. But I have an insulocentric bias about obesity and its host of associated medical problems. Insulin provides a framework which, so far, paints a consistent picture of the way life works. It has served me pretty well.

Time to hit "post"