What is the density of carbohydrates/protein/fat? [closed]








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As in weight per volume? I mean.. you always see them specified by weight but they have to have a volume, right?


I suppose different fat(for example) molecules would have different densities but then how do they universally have the same energy density? Are they converted to like a standardized type of fat? Thats the fat I'm interested in.




I assume the "energy density" you are referring to are the widely known statistics that:


* fat contains 9 "calories" per gram (actually kilocalories)
* protein and carbohydrates both contain 4 "calories" per gram


How can all fats contain "9" kcal per gram but have different mass densities? Here are a couple of reasons:


* The 9 kcal/g figure is an approximation that assumes a typical dietary blend of fats. The figure would if considering chemically pure fat molecules.
* The mass densities of most common fats doesn't vary that much. The densest "fat" molecules are probably the *extremely* short chain triglycerides like [triformin](https://en.wikipedia.org/wiki/Triformin) and [triacetin](https://en.wikipedia.org/wiki/Triacetin). They have densities of approx. $1.3~ \frac{\mathrm g}{\mathrm{cm}^3}$. These triglycerides have chain lengths of 1 or 2 carbons per fatty acid chain, a value far lower than common in natural fats. [Triolein](https://en.wikipedia.org/wiki/Triolein) is more representative of dietary fats and has a density of 0.95$~\frac{\mathrm g}{\mathrm{cm}^3}$. So the mass density variation among different fat molecules is pretty small: a 30% increase is all that is really possible.


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