What's the density of fat and muscle?

LumberJacck

Greetings all. Someone recently posted in another thread a photo similar to the photo below. You may have seen similar photos before.



Looking at the photo, you'll see muscle and fat with different densities next to each other. Maybe the fat is 3 times bigger than the muscle, as a guess.

That seems to contradict what I've read about the different densities, there being only about a 15-20% difference. I'm curious whether anyone can explain the difference between what I've read (0.92g/cubic cm vs 1.07g/cubic cm - via Wolfram Alpha) and the above photo. One possible explanation is that there are air pockets in the fat, but apparently there are not air pockets with the body excepting the lungs and digestive system. Any "holes" or "gaps" between things are filled with liquid having a density roughly equal to water, 1g/cubic cm.

Any ideas?

Sued0nim

What were the conditions under which the density was measured ..can you link your source?

Might it be something to do with water?

Sued0nim

That is the common visual representation of the two

LumberJacck

http://www.wolframalpha.com/input/?i=density+of+muscle

http://www.wolframalpha.com/input/?i=density+of+fat

Wolfram Alpha is a computational engine that uses journal papers to gather information and data.

I'm not sure whether water would have any effect, its density is halfway between fat and muscle.

yarwell

Might be adipose tissue, rather than fat. As you say the density of oil / fat is just under 1.0 g/cc which is why it floats.

Perhaps the photo it's just another bit of broscience. Some actual science says " Assuming that adipose tissue is composed of 84.67% fat, 12.67% water, and 2.66% proteins (27), the density of adipose tissue was calculated to be
0.9196 kg/l. " and then goes on to compare imaged volumes with mass of tissue in cadavers.

EvgeniZyntx

yarwell wrote: »

Might be adipose tissue, rather than fat. As you say the density of oil / fat is just under 1.0 g/cc which is why it floats.

Perhaps the photo it's just another bit of broscience. Some actual science says " Assuming that adipose tissue is composed of 84.67% fat, 12.67% water, and 2.66% proteins (27), the density of adipose tissue was calculated to be
0.9196 kg/l. " and then goes on to compare imaged volumes with mass of tissue in cadavers.

This. Conflate that with the fact that muscle tissue can volumetrically change by 20/30% over a few days due to normal water absorption (an positive effect of carbs in the diet) - a lot of the discussions about weight gained / lost due to changes in muscle to fat ratio are nonesense.

For example - I lost 7 lbs this week at about the same muscle level. Maybe a lb of that was fat - did I suddenly become denser? (Wait.. Don't answer that). Variable water weight is just a huge factor.

yarwell

http://www.ncbi.nlm.nih.gov/pubmed/8148928 "Adipose tissue volume was determined by hydrostatic weighing of all portions of the dissected adipose tissue. For the six cadavers, whole body adipose tissue density ranged from 0.925-0.970 g/ml." Ha. Busted !

EvgeniZyntx

yarwell wrote: »

http://www.ncbi.nlm.nih.gov/pubmed/8148928 "Adipose tissue volume was determined by hydrostatic weighing of all portions of the dissected adipose tissue. For the six cadavers, whole body adipose tissue density ranged from 0.925-0.970 g/ml." Ha. Busted !

Cadaver tissue might not be the best quality tissue...

yarwell

they were quite fresh ;-)

Let's face it lean competition swimmers don't sink to the bottom like this muscle density picture implies.