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If we eat fat:

Does the fat go into heart, arteries and fat cells.

OR

Is the fat digested, following which our body creates fat that goes into heart, arteries and fat cells.

Which one is right?

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2 Answers 2

up vote 6 down vote accepted

Fat is, in molecular terms, triacylglcerol. In order to be absorbed in the small intestine triacylglycerol molecules are broken down by lipases into fatty acids and monoacylglycerols. Once these have got across the enterocyte membrane they are reassembled into triacylglycerols and packed up into a special class of lipoprotein particle, a chylomicron, which enters the bloodstream via the lymphatic system.

The triacylglycerols in the chylomicrons are then able to be passed around through the system of lipoproteins (LDL, VLDL etc.) and pretty much can end up anywhere, including fat cells (adipocytes) or they can be metabolised as fuel molecules

So, because of that initial digestive step I would say that a single intact dietary fat molecule cannot end up as a body component directly, but complete metabolism of the components of the fat molecule is not necessary for these to contribute to body fat.

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It's more of somewhere between then. So they are broken and then reassembled into the same molecul? –  Jim Thio Mar 11 at 3:32
    
Yes, but the pieces that are reassembled are unlikely to have been derived from the same original molecule. It must happen occasionally I guess, just by chance. –  Alan Boyd Mar 11 at 5:57

Fat is digested just like any other food you consume, and eventually the energy you do not expend ends up as an energy reserve in shape of fat cells.

So, the second statement is right.

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