What is Trans Fat?

[mrmitchell]

I grabbed the wrong bag of chips the other day--usually I get Lay's Barbecue, but this time I got "Baked! Lay's Barbecue". The difference, aside from one being baked obviously, is that "Baked!" has 0g of Trans Fat in it (enough, though, to put the thing there.)

An asterisk after "Trans Fat" reads "* You should consume as little Trans Fat as possible."

Well, that's great. Pump my food full of **** and then tell me not to eat it.

I've heard that it is bad for you, and it's also in microwave foods and fast food, but what is it? Why is it bad? I'm talking about specifics.

[Provost Harrison]

A trans fatty acid is a form of unsaturated fatty acid that possesses stereoisomerism across one or more double bonds in it's hydrocarbon chain. As a crbon with a double bond forms a trigonal planar structure and pi bonding orbitals prevent rotation around the double-bonded carbon-carbon bond, the structure of the chain can be locked into two configurations...it can either be directly opposite on the corners of this C=C structure and be linear (trans) or be on the same side (cis) causing a kink in the structure of the fatty acid. Now enzymes are sensitive to this stereoisomerism and it makes the difference whether the cell can metabolise this chain or not.

[Provost Harrison]

(PS, you should know better than to ask a biochemist a question like that )

[SlowwHand]

http://www.enig.com/trans.html

[KrazyHorse]

That almost made sense to me.

[mrmitchell]

So basically they **** up your metabolism?

[Japher]

basically, it's fat you can't digest

[Boris Godunov]

Thank goodness "trans" doesn't stand for transitional, because then I would demand complete fossilized evidence of one kind of fat transitioning into another.

[/creationist]

[Dinner]

Trans fats are hydrogenated oils. Junk food makers love them because they taste and act just like but legally they don't have to be listed as fats on the food label.

The process of hydrogenation uses many chemicals and has been linked to cancer in several studies, yet, the major junk food companies continue to pack them in because they are cheap and fool consumers into thinking they're eatting healthy.

[mrmitchell]

Fat you can't digest? Does that mean it all goes to your lard or do you just **** it out unchanged?

And if it does all go to your lard, is it worth the loss of unhealthy stuff? For example my regular bag of chips had 15 grams of regular fat; the trans fat bag had 3 grams of regular fat

[KrazyHorse]

Junk food makers love them because they taste and act just like fats but legally they don't have to be listed as fats on the food label.

Probably because you don't digest them, therefore they don't add to caloric intake.

They should be listed, but separately from fats.

[mrmitchell]

But isn't this worse? They listed it as "Trans Fats" with a full asterisk. I've never seen an asterisk telling you to quit stuffing yourself full of regular fat.

[Japher]

It will just take longer to actually digest, raising cholestoral and other crud...

[gunkulator]

PH's excellent contribution aside, trans fats are unsaturated fats that are partially saturated to increase stability at room temperature and beyond. They are always man made.

Crisco is a good example of a trans fat product. It started as regular liquid vegetable oil and through a process called hydrogenation, was made into a semi-solid material. The extra stability gives it a long shelf life. It also allows you to cook it high temperatures without it breaking down into other chemicals.

Now the bad news. They are terrible for you. They raise LDL (bad cholesterol) and lower HDL (good cholesterol). You'd be better off consuming any kind of fat rather than trans fat. More bad news. They're everywhere. Any time you see "partially hydrogenated" oil in the list of ingrediants, you have trans fat. Food companies prefer them since they extend the life of food products that contain fat.

When the last round of changes to nutritional labels was put through in the US, companies were required to list total fat and saturated fat. Trans fat is not required to be listed. This should change.

[Provost Harrison]

They can be absorbed into the body but can't be utilised. They are dehydrogenated not hydrogenated...and here is a diagram to illustrate the point. Bear in mind that all enzymes work in a 'lock and key' manner - although in classical catalytic chemistry this isomerism will make very little difference, to an enzyme it is vital as it will not fit in the close fitting active site.