DEAR MARK: Fat Cells / Muscle Cells page

[chazglen]

I have heard that exercise and diet will change fat cells into muscle cells. Is that true? Counter to that, I have also heard that once a fat cell is created in the body, it NEVER goes away. It just stays there dormant and waiting to be fed again. The first condition, like the existence of Santa Claus, sounds too good to be true... while the second sends me into a purgatorial funk. Say it ain't so!

[lizch]

My name isn't Mark, but...

You cannot change a fat cell into a muscle cell through any mechanism--that would be like turning an arm into a leg.

My understanding is that you have a (mostly? totally?) fixed number of fat cells, and gaining fat weight causes each individual fat cell to increase in size. So losing weight is about shrinking fat cells and building new muscle fibers.

[BigRed]

I thought fat cells increased in size until they reached a critical mass at which point they divided. You are then stuck with them in a shrunken state crying out for food

The best answer to this is liposuction, that gets rid of them.

[Adrianag]

The best answer to this is liposuction, that gets rid of them.

Slightly OT but has anybody read the cover story in Wired magazine about the number of stem cells in lipo fat and the fact that they are using them to create breast tissue for reconstruction and to repair damaged heart tissue? Truly fascinating.

[lizch]

Fascinating, BigRed. Wikipedia says the same thing: "If excess weight is gained as an adult, fat cells increase in size about fourfold before dividing and increasing the absolute number of fat cells present"......"After marked weight loss, the number of fat cells does not decrease (the cells contain less fat)."

What a crappy system!!!

Still, no way I'm letting anyone near me with a medical-grade submersion-blender/vacuum combo.

[Lojasmo]

You can produce more fat cells, but cannot produce new muscle cells. Fat cells shrink when weight loss occurs, but cannot be changed into muscle cells. Diet and exercise will decrease the sizeof fat cells, but will not eliminate them.

[naiadknight]

NO! NO NO NO!
Fat cells do not turn to muscle. They turn to flat fat cells. If you create more musculature, it's created from scratch ingredients. You do keep the fat cells on hand, but if you don't fill your body with crap, you don't fill the cells.

[lizch]

Interesting, Wikipedia agrees that you can't necessarily increase the number of muscle cells either, but an individual muscle cell is unusual in being able to have more than one nucleus, and the number of nuclei CAN be increased. Fascinating stuff!

[Indiana Joan]

I would think, logically speaking, that unused fat cells would eventually disappear. Cells do not live on forever. All die eventually. And if an unused fat cell died, why would the body feel the need to replace it? Just a thought.

[BigRed]

I would think, logically speaking, that unused fat cells would eventually disappear. Cells do not live on forever. All die eventually. And if an unused fat cell died, why would the body feel the need to replace it? Just a thought.

I felt that way too. Unfortunately it seems that the body remembers how it was when it turned adult and in the same way that your height doesn't change (apart from stooping, compression of spinal column etc.) the number of fat cells doesn't change. See http://www.nature.com/news/2008/0805....2008.800.html

I don't know if all of these shrunken fat cells make you predisposed to gain weight easier, but it seems a fair assumption. Would liposuction affect this as I suggested earlier? I have no idea, I guess it depends where your body shape memory resides.