Fat Tissue Regulation ~ Part VII: Changes in Fat Cells with Weight Loss

I came across this one a while back and found it fascinating.

In this study, 8 overweight/obese individuals (4M/4F, 30-60 y.o.a., BMI ≥ 27, otherwise healthy) were treated with a very low calorie diet (500 cal/day shakes + unlimited veggies) for 5 weeks followed by a weight stabilizing diet for 3 weeks.  Abdominal subcutaneous fat biopsies were taken before and after the 8 week intervention.  

There's a lot more here than what I'll address in this post.  I hope to return to this at some future date, but in keeping with this series, I want to focus on the fat storage portions of the study.  I have quite a bit in the pike regarding fatty acid transport and storage in various cell types.  While fatty acids can be transported into (and out of) cells by passive means, it became apparent to me a while ago that the relatively rapid clearance of fatty acids into fat cells after a meal likely involved some active transport mechanism.  As it turns out, uptake of fatty acids by adipocytes is facilitated  by a fatty acid binding protein, FABP4.  Triglycerides are stored in adipocytes (and other cells) in what are called lipid droplets, LD.  Although the name implies something like a glob of fat, the lipid droplet is "coming of age" of sorts being recognized as a metabolically active organelle within the cell in much the same way as fat tissue has long since come to be recognized as so much more than just some passive depot for caloric excesses.  This study looked at a protein known as vimentin which is possibly associated with lipid droplet formation/organization.  More on this in a bit.

The table below summarizes the metabolic markers which were assessed in Week 6 immediately following the 5 week VLCD.  

So the subjects lost an average of 9.5 kg or just over 20 lbs body weight, 7.1 kg (almost 16 lbs) of which was fat.  Now I'm sure we'll get the usual "well, the diet was so low in calories it was effectively low carb" spiel as to why this diet worked, but such shake diets often do contain more carbs than some low carbers eat in a month.  In any case, let's focus on that dastardly hormone insulin.  Imposing a significant energy deficit on the adipocytes resulted in a more than 25% decrease in fasting insulin levels (the p-value of > 0.05 would not be statistically significant) and a 7% decrease in fasting blood glucose (the p-value of about 0.01 is statistically significant).    Check out those NEFA/FFA!!    Circulating free fatty acids were almost dropped in half!!  You see, when the 8 subjects were weight stable at approximately 20 lbs heavier weights, their blood was swimming with free fatty acids -- you know, those NEFA the low carb shills claim are being locked away in your fat cells by your carb-induced insulin baths.  

Here's what else they found:
... the uptake of fatty acids seems improved because on average there is a 40% increase in the abundance of FABP4 after the intervention. ... this provides evidence that weight reduction, in particular loss of fat mass, stimulates the basal function of triglyceride storage by adipocytes.
Note the adipocyte proteins were assessed after the full 8 weeks (3 weeks energy balance) so that the effect of an energy deficit was eliminated (or at least mitigated).  From a formerly obese point of view, this is somewhat depressing news as always.   At first glance, it seems that losing weight only primes the fat cells to gain it back.  But let's pan back a bit and look at this whole picture of the purpose of our fat cells:  to store energy for when we need it and keep excessive levels from circulation.  So this is actually good news!  Just 5 weeks and adipose tissue is dramatically transformed from overfilled and dysfunctional to doing it's thang protecting your non-adipose tissue from metabolic damage!

But here we see yet another contradiction in the woefully misguided TWICHOO.  Yes, folks, what happens when you lower insulin, as was done in this study?  The fat cells seem to have established a more fat-accumulation friendly environment upregulating FABP4.  But something else also happens, what is described as "a reduced intracellular scaffolding of GLUT4"  Hmmmm.  So fewer glucose transporters but more fatty acid transporters.  Remind me again what we store in our fat cells?   Perhaps some comedians should stick to their day jobs rather than formulating garbage theories about how our fat mass expands to accomodate glucose.  Sigh.  But to sum up:

  • Before:  Higher insulin, higher GLUT4 scaffolding (to support glucose transport), lower FABP4 (to facilitate fatty acid uptake), elevated circulating NEFA.
  • After:  Lower insulin, lower GLUT4 scaffolding, higher FABP4, lower circulating NEFA.
Fat cells don't go wild accumulating fatty acids, rather they're fed up and just can't take it anymore!  OK, sarcasm aside, this is yet another study that shows some rather dramatic changes in metabolic health with relatively minor changes in weight.  I believe the findings here are important with respect to hormones and circulating metabolites.  Although not statistically significant (probably due more to the small sample size and variation in levels than anything), the observed drop in fasting insulin levels of 25% is physiologically significant, and yet this was accompanied by an only 7% reduction in fasting glucose.  What, yet again, seems to have changed the most?  Those NEFA.  

I'm going to save my analysis of Keith Frayn's latest review paper for the new year, but the findings here dovetail nicely with Frayn's more recent thinkings on fatty acids.  Specifically, that adipocyte IR on the release side (inefficient suppression of  HSL )  may be less important in the etiology of metabolic syndrome and diabetes, but rather that the defect occurs at the uptake side of the equation.  This leads to inappropriately elevated basal circulating free fatty acids as well as inappropriately elevated postprandial NEFA with the composition of said fatty acids being potentially troublesome.   Both lead to too much fatty acid storage in inappropriate places.   Metabolically healthy lean individuals would have highly responsive fat tissue, presumably with sufficient FABP levels to whisk fat out of the bloodstream when called upon.  That the obese have less fat accumulating proteins than their leaner selves is also in contrast to TWICHOO.  The leaner "after" folks here had a more fat-trapping milieu than their "before" situations.  The lean generally trap fat very  efficiently (though some with insufficient adipose tissue do not).  Clearly, the individual components of what drives fat uptake/esterification and lipolysis/release, do not regulate the NET accumulation of fat.   This study adds to the evidence in support of this statement.

Before I go ... speaking of Frayn ... If you're relatively new to the Asylum, you may hear his name bantied about here often, but I've not blogged all that much on his work of late.  If you don't know what I was talking about just now, may I suggest the following older blog posts (in reverse chronological order):  Fatty Acid Trafficking , Adipose tissue as a buffer for daily lipid flux ~ Keith Frayn 2002 , Non-esterified fatty acid metabolism and postprandial lipaemia , Insulin Resistance ~ Taubes v. Frayn.


bentleyj74 said…
Very interesting. It sort of looks like regardless of macro ratios...being metabolically lean will help the body do it's job more efficiently. Am I reading that correctly?
Sue said…
The modifast 3 serves = 500 calories has about 58g carbs and 52g protein. Plus the unlimited veg will add to the carb count.

A good amount of fat loss with not too much muscle loss. probably good macro percentages for such low calorie. I wonder if it was mostly composed of protein and ver low carb whether there would be more muscle loss?
Lerner said…
If you're not all aware, there's a new kid in town, PrimitiveNutrition on youtube with a long series of fairly well-made videos:

which prompted a long post by Minger:


It seems the myth of Keys the Great Deceiver is partly crumbling... but then all becomes advocacy again in her post - as always on both sides.

Also here:
CarbSane said…
Hi Lerner ... I wonder if someone could run the narrator of that YouTube series through a voice analyzer with Don's voice ;) I wondered "aloud" on Twitter if he was behind that series. I don't really have the stomach for 71 videos! Yikes!! But have listened to a few parts. Whoever PN is, makes some good points.

Thanks for that info Sue. At some point I don't see how low carb low cal (thus limited protein to some extent) wouldn't cause more LBM losses. No way glycerol from fats can provide all the glucose needs so some protein's gotta go!

Yeah bentley I think you're reading right if I'm reading you right! It's an interesting paradox that the most metabolically healthy would be the most prone to obesity if Taubes' theories were correct. In theory there shouldn't be any metabolically healthy lean people, as they would all get fat and eventually unhealthy ... hmmmmm.
Sue said…
Yeh saw all that. Did you see Don's B12 post.

He is a vegan now:
Sue said…
"At some point I don't see how low carb low cal (thus limited protein to some extent) wouldn't cause more LBM losses. No way glycerol from fats can provide all the glucose needs so some protein's gotta go! "

yeh, that's what I think.
bentleyj74 said…
I hate to engage in macro comparisons because in the bigger pic it looks like it probably doesn't matter but I have heard that carbs are protein sparing. If that's true carbs would be the way to go for low cal preservation of lbm.

If not, nevermind ;)
Lerner said…
As I'd just posted at Masterjohn's, Minger's article seems to give the impression that accounting for a country's prosperity wrt mortality is something new. But that was all thrashed out years ago, e.g.:

Dietary Factors and Coronary Heart Disease

Masironi 1970


wrt per capita income and per capita
energy consumption
Lerner said…
Sue, I skimmed the B12 post (most blog articles around are getting too long, but that's probably related a lot to defensively anticipating criticisms). It was illuminating about B12 requirements - if true.

(I'd wish for all blog posts to have a summary box at the end, btw.)

wrt LBM and weight loss, bodybuilders are nothing if not dedicated - that includes devotedly experimenting with everything. I'd say their practice through the years when dieting before a contest was to eat lean chicken and maybe broccoli or other non-starchy vegetables. The ingested protein would also serve for gluconeogenesis - rather than burning muscle. Most important is to send the signal to "keep this muscle because I'm using it" via exercise.

Naturally, mesomorphs and steroid users retain more. That includes the steroid users who swear that they don't use steroids, but only use their magic routine or feeding patterns.

Last but not least, there must inevitably exist a magical guru on the internet with a magical approach and hence lots of followers... aka Martin Berkhan & his "leangains".
bentleyj74 said…

I wonder if he'd like this [it is pretty funny but not g rated]. I'd have an easier time taking her seriously if it weren't for the obvious boob job and trendy clothes :)

Still, that grain of truth is as true as any other.

CarbSane said…
@Sue (and all really): I found Don's podcast with Jimmy rather enlightening (it aired alongside Durian Rider's). I hadn't really followed his blog much but did read the occasional post someone would link to. It was distracting and disturbing how he kept turning to his new wife for answers. He never explained his change of heart from an evidence standpoint -- well, he writes rather convincingly of his positions at the moment, but he didn't clarify why he no longer holds positions he once did, e.g. here's my new evidence sort of stuff. If memory serves he says he started to experience negative things within the first year of his former diet, but he persisted for like 14 years? And he still has the book for sale?? I don't gettit.
bentleyj74 said…
Ha! So I wasn't the only one going..."didn't his wife used to be called Rachel?!"

There is a new wife! A new day! A new Don rockin' the new year vegan style baaaaaaybeeee.

Guess he's not getting any repeat invites though.
CarbSane said…
@Lerner: I feel compelled to apologize for my lengthy posts now! LOL. I can't speak for others, but I just sort of start typing. I probably spend too much time doing this as it is, so I just "let'er rip" and don't do too much in the proof-reading and consolidating department. A summary at the end, however, sounds like a good idea. I might give that a whirl in the New Year. :)
Lerner said…
oh boy, I had commented on PN's youtube #36 to this effect: @3:10 he shows on the screen words from Keys about controlling calories and fat - yet the voice-over only mentions the fat. I compared this to the way that Paleos disregard Lindeberg's conclusion about "leanness" the Kitavans being a big factor in their health.


Somehow that comment didn't make it past the censor. But my other comment posted afterward did.

So I suddenly lose all interest in that crap.
Lerner said…
Evelyn, the length is fine if you have a summary :)

Even my comments get longer, as before I hit 'send' I now typically analyze what someone might interpret differently from what I actually meant - then I add more to clarify.

Sometimes though I just hit send without editing and then somebody usually thinks I was criticizing them :)
Lerner said…
I did see Durian (30-bananas) videos for the 1st time yesterday. Because of his genetics and activity level, he'd be lean no matter what he ate. If he ate lots more protein and calories and lifted weights, he'd likely be beefy.

The thing of interest from him was that he doesn't require much protein - but then he isn't building new muscle, he's just maintaining. He does, therefore, put a pin in the dogma that everyone who exercises needs exorbitant amounts of protein just for repair and maintenance.

I do like the accents they all have.

Speaking of genetics, see a "myostatin negative" whippet:

There are also net photos around of bulls and even a human toddler.
bentleyj74 said…
He looks dreadful but he is lean, I'm totally with you on the accents though.
LeonRover said…
It's your New Year's ReFrayn

How 'bout them NEFAs?

Keep up the good work.
Keenan said…
You need very little protien to preserve lean mass, this is why big guys(muscles) can go on raw vegan diets and maintain pretty much all there mass. Actually gaining muscle is a whole nother story
Sue said…
Lerner I just think the bodybuilders will probably be having a lot more protein during the cutting stage and not so low calorie as in this study. I don't think in this study the amount of proteins and calories would be sufficient to avoid muscle mass breakdown if it was mostly protein and very low carb?
Mzlittlekitten said…
Hi on youtube i have come across a raw food vegan who recently set himself a challange to gain 30lbs of muscle in 100 days.So far he says he is very close to his goal but will need to burn off any extra fat he has accumulated during the challenge.Of course,his results would need to be independently verified but judging from his various weightlifting workout and one armed pullup videos his strength is definately real.

Sanjeev said…
It's either a joke or something is SERIOUSLY FISHY[0] there.

Lots of absolute beginner weightlifters taking serious roids don't gain that much muscle, that fast, without also putting on lots of fat.

Completely CRAPaliciously, bullsh*ttingly BOLLOCKS. IMHO, of course.

He must think he's completely gulled his target market and they'll now accept anything: towards that video's end he claims 2 to 3 hours sleep per 24 hours over the previous 27 days.

He should have made these claims to the JREF before starting, he's straying so far into that territory I bet they might have been interested.

[0] liar, liar, organic underwear and pants on fire
Sanjeev said…
Ferriss claimed even less than this guy did, and most folks who've been around the weight room didn't take Ferriss's claims at face value for a second; many outlined specific ways Ferriss could have cheated, using techniques Ferriss has written about in the past.
Mzlittlekitten said…
I see what you mean,without an independent observer verifying his statistics and diet, the claims are worthless.I just wanted to show that there are others besides durian rider and doug graham who live off carbs without completely losing their muscles and strength.
CarbSane said…
Welcome Rip & Clip!

Yeah I think this must be true. OTOH, there are those eating VHF VLC doing IF and all that -- in other words not a lot of calories and protein. I can't imagine the rapid losses aren't at least some muscle loss.

Speaking of muscles though, Sisson is big on how he does no ab work. Well, he's lean, he was a well conditioned athlete for decades, and he DOES do isometric contractions.
Key said…

He hasn't gained any weight yet though. I'm seen people try these gain muscle on raw diet dealios, I'm never seen any of them be succesful and in my expierence most just abadon it.

No one gains muscle without eating enough protien, maybe strength but not actual weight/muscle. Strength is more a psychological deal, it has little to do with actual muscles.
Lerner said…
Sue, you are right and I am actually surprised that the muscle loss was so little. AFAIK, carbs as muscle-sparing was always pretty much the rule in times past. I don't know what LCers have concocted as an alternative theory. But IF is said to be muscle-sparing now.


wrt to the 35# gain vegan, the natural inclination is of course to look for tricks. We don't exactly live in the Age of Honesty. I've seen UFC fighters show up on fight day at 10 pounds over the limit - legally so because some are very proficient at cutting weight of 10 pounds for weigh-in day. Just drinking water will quickly get most of that back. Then a person can gain an additional 10 pounds of water with creatine. So now the goal is reduced, to starve and lose merely 15 pounds, then regain, which is easier than initial gaining.

It's still interesting if that can(?) be done on vegan.
Sanjeev said…
> AFAIK, carbs as muscle-sparing was always pretty much the rule in times past
The idea that most LC'ers buy is that ketones in and of themselves (not any side effects of ketones or their metabolism) spare protein.

I think ketones are involved, but not the way they think - from memory, ketones induce some insulin release, and it's the insulin's anti-catabolic effect that's protein sparing for highly ketogenic diets (personal theory, likely wrong).

I believe myself most of the protein loss from very restricted calories is in the delta, not the steady-state maintenance - it's in the body handling the calorie and composition changes, not in the long term maintenance.

> Strength is more a psychological deal, it has little to do with actual muscles
Kind of ... there are physical changes like the brain/spine/nerves/end plates all change the way they fire muscles (called "rate coding"), and the nerves conduct better, and recruit more fibers, and there's improved co-ordination among various muscle groups ... all yielding better strength with no muscle weight gain needed.

But gaining strength without gaining weight requires some specific types of training. I don't think it happens in general ... in general, the bigger you get the stronger you get, and the stronger you get, the bigger you get.

Many folks suggest doing that specific type of training for limited periods - it strengthens muscle faster than tendons, ligaments and joints.
Sanjeev said…
> proficient at cutting weight of 10 pounds for weigh-in
This was one of the specific accusations levelled at Ferriss.
Karen said…
Thot Id try to get on again!
CarbSane said…
Welcome back Karen!
Karen said…
Thank you Evelyn!!