Is it the same as the volume of a pound of lard or butter that you buy at a store or does bodyfat have more water than store bought fat.
It depends if you actually mean “fat” or “adipose tissue” Adipose tissue is composed of fat cells - called adipocytes, which store fat, but also contain quite a bit of water, and so is slightly more dense than pure fat alone. What most people mean when they say body fat is adipose tissue.
So, I’ll go ahead and do the math for fun:
Water is 62.4 lbs/ft^3 so 1 pound of fat is:
x ft^3/1 lb * (1 ft^3/62.4lbs) * 0.91 (note: I used an average) * (1728in^3/1ft^3)
= 25.2 in^3 (approximately)
This equals a cube of about 2.9 inches per side or a sphere with a diameter of 3.6 inches. Sigh, doesn’t really seem like all that much does it?
Also, given that the surface area of your skin is about 1.8 square meters (2790 square inches), it would be a layer of fat .009 inches thick all over.
That doesn’t make sense to me, I just saw something on TV where a kid was trying to lose weight and a nutritionist gave him a latex model of 5 lbs of fat and it looked like a large loaf of bread ie this . Five 2.9" blocks wouldn’t come near the size of that. It specific gravity would be less than 1 though since fat floats.
Well, I’m pretty sure my math is correct (maybe someone could double check). Too bad there’s nothing to use for scale in that picture you linked. I think five 2.9" cubes would be the size of a small loaf of bread which is kinda what that picutre looks like.
Lesse, I’m guessing the average loaf of Wonder Bread is something like 4"x4"x12" which is 192 in^3. Five times 25.2^3 is 126 in^3, about a third smaller than the loaf. Isn’t bread usually sold in one pound loaves? I can’t find a site that lists the average density of bread tho’…
Looks good to me.
Here is a scale picture. The original site says the dimensions are 15x6 (it says under the ISBN and price in the right column). 15x6 sounds similiar to the size of the 5 pound fat log that the kid on TV was holding. If you took four 2.9" cubes and put them together you’d get a square that is 5.8x5.8x2.9. Add in the volume of the fifth cube to the 5.8x5.8 square and you get something that is 5.8x5.8x3.625. This isn’t close to the 15x6 that the 5 pound model claims. I have no idea what the 3rd dimention for that model is but looking at the picture
Your math is correct, I just don’t believe that bodyfat is as dense as the numbers astro listed because if they were those models would be wrong and those models are likely alot closer to the actual volume of fat and were probably designed by health professionals since they are sold by legitimate companies that deal with models for anatomy and physiology.
You also have to take into account the volume of things like blood vessels to supply the fat. I once heard (I don’t know how true it is) that every pound of fat requires 2 miles of blood vessels, so adding in the volume of capillaries as well as other cells and tissues which may be necessary to assist the adipocytes could give a bigger volume.
In my Weight Watcher’s class, the teacher always had us visualize sticks of butter. According to astro’s cite, butter and human fat have approximately the same density. So wouldn’t a pound of fat look pretty much like four sticks of butter? That’s 2.5" x 2.5" x 4.75" or about two cups of fat.
Next question, from billshakespeare:
How much does a pound of flesh weigh?
(Merchant of Venice)
Umm… not to burst your bubble, but that yellow cheese log o’ fat model is being sold primarily as a novelty item, and I’m going to bet that less math went into that model’s “best guess” construction than termorviolet went through in his/her calculations. Plus the model is full of valleys and twists. Get an empty gallon milk jug and fill it with 5 lbs of water then add 10% to the height. I think you’d be surprised how compact it is.
Finally here is another reference for human fat listing it as .903
Engineering reference tables- constants of oils and fats
(pdf file)
Human fat :
Fat or oil Solidification point, = 15 °C
Specific Gravity @ (15°C/15°C) = .0903
Refractive Index = 1.460
Saponification Value =193-200
Iodine Value =57-73
You would be surprised just how little volume two miles of (primarily) capillaries will take up. Remember, capillaries are extremely thin, and they’re packed in such a way to make the total volume per unit length very small.
I’m not gonna argue (beyond this post, anyway 
) about it but if you go to the My Pet Fat website (what a weird concept, BTW) and look at the bigger picture, it looks to be about the size we figured (that’s definitely smaller than a loaf of Wonder bread). The one pound model looks to be about the size (3.6" in diameter) calculated, as well. I’m satisfied anyway…
Ok you guys are right. I saw a 3lb jar of crisco, which is 12g/tablespoon. A tablespoon is 15ml so that is a little less dense than bodyfat at 0.8 but still a 3lb canister is very big and I can see how 1.7 of those containers could have the same size as the novelty item I keep referring to.
tremorviolet
Using this online calculator:
http://www.1728.com/density.htm
the volume I got was 30.417 cubic inches
I’d say you multiplied by .91 instead of dividing by it.
If a cubic foot of water weighs 62.4 lbs then 1728 cubic inches of water also weighs 62.4 pounds.
Dividing we get: water = 1728/62.4 OR 27.69 cubic inches per pound.
Since fat is less dense than water, it would take a greater volume of fat, to equal 1 pound.
27.69 / .91 = 30.43 cubic inches which is in fairly good agreement with the online calculator.
I’d say the small variation between 30.43 and 30.417 is due to the fact that a cubic foot of water weighs 62.428 pounds.