I’ve heard that there are a finite number of fat cells, you have what you have and you can’t lose them unless you have liposuction.
If so, how does one “burn” fat? Are you just decreasing the size of the fat cell? Is there a limit on how big a fat cell can get? How do they determine %body fat? Is it a volume vs. quantity thing?
I am not a doctor so this should be qualified. I beleive you are generally correct. I think that it may be possible to lose fat cells with extremely hard work. I think that gaining fat cells is easier.
You have a certain number of fat cells. They can get fatter, but the number does not increase.
There are 3 different tests used to measure the % of fat: skin caliper, bioimpedance, and water immersion. Water immersion is the best, but most difficult and most costly. Skin caliper is the easiest and usually free. Bioimpedance is also easy.
Skin calipers and bioelectric impedence each carry a fairly big margin of error. One should take results from either of these tests with a grain of salt. Water immersion (hydrostatic weighing) is the most accurate. Some universities that are equipped for it will perform the test for a modest fee.
I underwent hydrostatic weighing once, and it’s a neat procedure.
Adipose cells look a lot like a signet ring from the side: round, with the nucleus squished up against the edge, and the center all full of fat. Lose weight, and these fat cells just empty out, and are always waiting there to fill up quickly with any fat they can get, unless you remove them thru liposuction. This is one reason weight is sooooo easy to put back on.
But you can grow more fat cells! This takes more energy of initiation, and generally only happens once all current adipose cells are full, but once the anabolic process of adipose cell replication is underway, they reproduce quite rapidly. Then they can’t be got rid of either, only emptied out!
Qadgop, MD
For a good look at what Qadgop is talking about with the shape of adipose cells, check out:
http://www.pathguy.com/histo/064.htm
Paperbackwriter’s link shows that there are two kinds of fat: white and brown. Since brown fat is rich in mitochondria, it is not bad fat, but a source of energy. Perhaps Quadgop the Mercantan can expound on that.
I just wanted to break in here and say that Ed, the guy who runs http://www.pathguy.com, is my fraternity advisor here at the Univ. Mo Kansas City. He’s a really nice guy, and a certifiable genius.
–Tim
The human body has a very small amount of brown fat, and does not produce any more. It is often quickly used up when your first born.
Thanks for all the replies.
So, IS there a limit on how big fat cells can get? Qadgop says that you can make more once the ones you have are full but what, exactly, is full?
Tell him he’s welcome to come fight ignorance with us anytime on the SDMB. I found his site a year ago and I love it. I especially like the bit about Virchow, who is a bit of a hero of mine.
I would just add that they can measure body fat by dual X-ray absorbance and it’s more accurate than water immersion. Not my area, but I recently participated in nutrition research study by the USDA.
Simplistically, lean muscle and fat absorb X-rays differently; my body fat was measured by laying down and having the ‘X-ray scanner’ pass over me. Given my height, weight, bone density, and ect., my body fat can be accurately calculated. Or at least more accurately than calipers or water immersion.
I was measured at 18% by this method (which is in normal, healthy range for a male). I’m no longer an active sports playing teenager or 20 something and I’m beginning to deposit fat (or my fat cells are getting larger) as I get older; but most people would consider me fairly lean (I still wear the same waist size jeans I did in highschool).
You have to take into consideration how your body fat is measured. I hear guys at the gym that claim they have 8-10% or even less body fat and they’re no leaner than me. You hear about pro athletes having like 3% body fat. That’s BS.
Of course if you’re intersested in knowing your body fat, it’s nice to get somebody like the USDA to pay you for a nutrition study instead of you paying some commercial company.
If I’m wrong about the dual X-ray compared to water immersion, I’d like to hear it; because that was specifically asked of the researcher at the subject screening. I hope I wasn’t BSed (and I haven’t bothered to check for myself).
I heard Frank Shorter had 4% body fat. I’ve had mine measured by calipers and bioimpedance at 16%, but people say there’s no way I’m over 10%. I think 4% is the bare minimum you can have without getting into trouble.
I’m not sure–barbitu8-- about values measured by other methods; that was sort of my point…
Now I have to go search, but 4% body fat? I still think that’s BS. There’s a difference between subcutaneous fat and total body fat.
You hear values of body fat of guys like Jordan and Shaq that are low single digits. How was it measured?
In my own experience, there’s a guy at my gym who’s a Olympic class rower (I don’t know rowing, but supposedly he’ll be competing at the next Olympiad, whatever…). He claims to have something like 5% body fat and he told me I looked like I had 8%.
I told him I had just been measured at 18% by the USDA study and he didn’t buy it. He told me if I had 18% body fat, I would be quite pudgy. Well, as the researcher at the USDA put it, most people overestimate their heigth and underestimate their weight–that’s why we were measured for the study and our word wasn’t just taken.
Nobody wants to hear that their body fat is a lot higher than they thought.
Like I said, now I’ll have to go do a search, but I’m real skeptical about these single digit body fat measurements.
People have a misconception of percentage of body fat. 18% would not be pudgy. The lowest “normal” % is 17. Anything under that is considered low,which, as you know, is not bad, unless it gets too low.
In females, if they get too low, they lose their periods. They need more fat than males, and I would guess that in females anything under 12% is bad. I read once that 5% is the lowest for health. As you know, even males need a certain amount of fat for various reasons: cushioning organs, etc.