Ectopic Fat

A nice overview I just thought I'd share here.  Ectopic Fat Depots and Cardiovascular Disease

Waist circumference was one of the earliest means of quantifying body fat distribution, and some clinical guidelines have recommended measurement of waist circumference to provide additional information regarding cardiovascular risk.
4 However, waist circumference consists of both subcutaneous adipose (SAT) (classically nonectopic) and visceral adipose tissue (VAT) (classically ectopic). This is important because VAT is associated with more adverse levels of metabolic risk factors compared with SAT.5 In addition, seminal work in mice has shown that transplantation of SAT, but not VAT, to an intra-abdominal site resulted in beneficial effects on metabolism.6 Taken together, these findings suggest that information about body fat distribution beyond waist circumference may provide important insights into metabolic and cardiovascular disease risk.
There's much more but one of the issues that is confusing is the role of abdominal fat in disease/risk.  Not all apples are the same apparently.  This reminded me of a post Stephan wrote a while back:  Is it Time to Re-write the Textbooks on Insulin and Obesity? Part II.  It contained this picture and caption.  
This is a photo from a paper titled "Insulin-sensitive Obesity" (2).  According to the paper, that gentleman has a low insulin level similar to a lean person, and normal insulin sensitivity, despite having a body mass index of 45.2!  This is true of a significant fraction of obese people, and it has been replicated in other studies  (3).  What differentiates insulin-sensitive from insulin-resistant obese people?  Inflammation (2).  Imagine that!


There was a fellow from the raw-vegan camp (yes, high fruit by way of 80-10-10), who posted up a video of his DXA scan. On the surface and through conventional gym-based measurement methods, he would've easily been sub-10% body fat with a very lean waist and visible musculature. However, the DXA scans showed that he had a lot of body fat that was hidden beneath the toned body, especially around the abdominal region. His actual body fat level was around 18% as a result of this scan.

I don't know whether the textbooks require an absolute re-write, but popular conception most certainly requires more depth and discretion that goes beyond this intellectually stunted nonsense about 'skinny fat' and 'pot bellies'; neither of them being relevant to the individual that I speak of in the paragraph above.
Sanjeev Sharma said…
I think I saw that: the DXA was wrong in his case.
carbsane said…
How did I not recall James' article on DEXA!!! Sure does put Jimmy's claims of building all that muscle in 2 months (during which he reinstated regular lifting) in perspective ;-)
carbsane said…
Stephan's title referred more to the hyperinsulinemia/IR chicken/egg debate than the fat distribution, just I recalled that image when I was reading this paper.

I guess obesity is now a disease so it's too late I suppose, but the truth is that while most obese suffer some health complications, it is more those with a particular type of fat. I hate that my health is considered "at risk" merely because of BMI. If I had whacky lipids and such that would be a different story ...
I thought that he had resolved to gain muscle mass. Now I'm starting to wonder if we are talking about the same person.
Yes. I think BMI is a very general tool and means nothing beyond that point. It fails to account properly for ectomorphs, bodybuilders or even individuals with a stocky but otherwise healthy physique with no negative metabolic markers.
Karin said…
I notice the person in the above picture has what looks like soft fat and if you pushed on his stomach it would feel squishy. My dad has type 2 diabetes, and has had it for at least 15 years. His stomach is huge, but it has always felt as hard as rock. When I hug him it's like he has a basketball under his shirt. I read somewhere (Eades maybe?) that the squishy fat is SAT and the hard as a rock fat is VAT. My dad's situation seems to bear this out since he has diabetes. Is that observation true across the board? If so, it seems it would be fairly easy to if an obese person has mostly SAT or VAT.
carbsane said…
I think the VAT is hard to see if there is substantial SAT, and there was that British series on The Men Who Made Us Fat or something where the rather slim reporter had a scan done that showed a lot of visceral fat. But yes, the hard "beer belly" is the worst kind of fat, metabolically.
Myron Schwarzennecker said…
I'd like to see a photo of the entire person as that might be revealing. If he is got skinny or fat or stocky/muscular arms, e.g.
Myron Schwarzennecker said…
All in all, it's pretty much saying that the towel has been thrown in when it gets down to whether one type of fat from habitual overeating is good and another is bad, instead of eliminating the overeating.
Myron Schwarzennecker said…
From this week, "People eat less after harder workouts: small study"

After the sessions, the men ate 764 calories after resting, 710 calories after the moderate exercise, 621 calories after the high intensity workout and 594 calories after the very high
intensity workout.
Myron Schwarzennecker said…
Question 1: is fat ever accumulated outside of cells? What about in so-called marbling in meat? How about fatty streaks in the liver (is that extracellular or only in hepatocytes or maybe macrophages/Kuppfer's)?.

Question 2: if you looked at VAT versus SAT using only a microscope, could you see the difference? What about with staining to see intracellular components? What about with immunostaining to see surface proteins?
Sanjeev Sharma said…
> What about in so-called marbling in meat

most of the fat there is fat cells outside the muscle cells but within the muscle tissue.

> is fat ever accumulated outside of cells?

I think almost all of these are disease processes ... fatty arterial plaques would be the only significant fat outside of cells ... maybe in fatty liver?

I don't know if lipomas ever occur extra-cellularly.
Sanjeev Sharma said…
I don't have the studies handy and it's probably impractical to use this effect but I think it's fairly well established that when one goes into calorie deficit trans fats are preferentially mobilized for energy first, polyunsaturates next and saturates next.

Or more accurately, of the fraction of fat that's being oxidized, the fraction of trans fats being oxidized is very high relative to how much trans fats exist in the body. If one stays in calorie deficit The body's trans fats will disappear long, long, long before the other types.

the fraction of polyunsaturates being mobilized relative to how much is stored is lower than for trans and higher than for saturates, and so on
Myron Schwarzennecker said…
So fasting might be a good maneuver to burn off possibly harmful TFAs? I know there has been controversy on whether even the naturally occurring TFAs are medically harmful or not (with Paleos insisting that 'natural' can't be bad, of course).

But sorry, I was unclear, I meant that the distinction of fat *stored* as VAT or SAT being good or bad (or neutral), was just throwing in the towel. Though some will say that it's impossible for them to lose weight.

Question: in all the hypocaloric metward studies, was any
subject ever released due to a medical urgency from their not being able
to handle the calorie restriction? In other words, many will say that undereatiing makes them sick, but is there a basis to that other than mere self-perception? Can practically all people just tough it out, or is that medically impractical?
Sanjeev Sharma said…
> might be a good maneuver to burn off possibly harmful TFAs?

That's an idea that would need to be tested.

I could imagine that "force-feeding" or "fire-hosing" a bunch of TFAs into your blood/liver/brain/whatever and through your mitochondria in a short time, which fasting may do, may not be as healthy as going into slight calorie deficit and letting the TFAs trickle out (assuming a small deficit will allow a trickle, not a dump)
carbsane said…
This is something I often wonder about, re: marbling. If it's in fat cells within muscle tissue as Sanjeev suggests, how did the fat cells get there? And yet I don't think it can be fat in a muscle cell or that a muscle cell can de-differentiate and become a fat cell. I'd think it has to be in some cells but dont know for sure.

I saw a lot of VAT in my days of animal research and it does look different to SAT that I also saw a lot of in cadavers. Could be species but I don't really think so. It's a texture thing.