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Transfats vs. monounsaturated fats

  1. Feb 16, 2007 #1
    with all the health advisories against consuming transfats, how can monounsaturated fats be good for you then? I would think that monounsaturated fats would be mixutures of cis and trans isomers, this cis being the healthy version. So why are foods that are rich in monounsaturated fats still considered as being healthy? do foods that are labeled as containing monounsaturated fats only have the cis isomer of the unsaturated fat?
  2. jcsd
  3. Feb 16, 2007 #2
    Because most fats are cis and not trans...

    also, unsaturated fat is more healthier than saturated fat...
  4. Feb 16, 2007 #3
    so if monounsaturated fats are mostly cis, why is there a preference for nature to produce cis fats instead of the trans version?

    yes i know.
  5. Feb 16, 2007 #4
    Most likely because cis (c-shape) is a more efficient geometry to stack together than trans (s-shape) to form complex molecules--see here for one explanation:
  6. Feb 16, 2007 #5
    It all comes down to how much energy the body can derive from the fat molecule. Our body is able to derive more net energy from saturated fats then monounsaturated fats. This is due to monunsaturated fats having a double covalent bond some where along the fatty acid chain that saturated fats dont have. Saturated fats contain fatty acid chains that contain only single covalent bonds, which makes it easier for our body to break down. Trans fats are unsaturated but there chemical structure makes these fats behave more like saturated fats than like unsaturated fats. When you are trying to lose weight obviously you would want less energy from fats, hence monounsaturated fats are better for consumption.
    Last edited: Feb 17, 2007
  7. Feb 17, 2007 #6


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    Where did you get that information, that saturated fats are more fattening and thus unhealthy?

    It all comes down to the melting point of saturated vs unsaturated fatty acids. Unsaturated fats are more liquid at body temperature and thus are less likely to deposit on your arterial walls etc.
  8. Feb 17, 2007 #7
    From a human nutrition course I took. Supposedly when unsaturated fats are broken down for energy, it requires more ATP to power all the enzymes then a saturated fat due to the double covalent bond located along the fatty acid chain. Since fats provide the same overall energy but it takes more atp to break down unsaturated fats, the body recieves less net energy from unsaturated fats.
  9. Feb 23, 2007 #8
    I must be really out to a saturated fat lunch! My layman's understanding is that i) unsaturated fats are easier to break down because the double bonds are more fragile than single bonds, and ii) cholesterol acts as a detergent to help break fatty chains down into more digestible bits. Therefore saturated fats, being more stable, cause the body to produce more cholesterol, some of which ends up in the arteries.
    I thought this was something I understood - - at least at a simple conceptual level. But I llike being being shown where I'm wrong. So if someone can set me straight, please do.
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