T Nation


What exactly is a trans-fat?, cause we are always talking about them here, I thoguht there only things that said Hydrogenated or Partially Hydrogenated.

Saturated fats are all single bonds and each carbon is saturated completely with hydrogen. In monounsatured and polyunsaturated fats, there are double bonds. The carbons connected to these double bonds have only one hydrogen bonded to them.

At a double bond, you can have one of two arrangements: cis or trans. It refer sto the shape of the chain (without a blackboard, I can't draw it, so head to a bookstore and pick up an Organic chemistry book and look up cis and trans isomers). In nature, all fatty acids are of the cis isomer and this is what we are accustomed to handling. When fats are processed though, sometimes the trans isomer is created. While chemcically the same to the cis isomer, the structure of the compound is different and our bodies cannot handle them.

Hope that helps!

So people are saying stuff like Soybean Oil or Peanut oil is a “trans-fat” is that true or what?

Any polyunsaturated oil can form trans fats when heated to high temperatures. Soybean and peanut oil by themselves do not contain trans fats. The keys words to look for are “hydrogenated and partially hydrogenated”. Also, pay attention to things that are roasted in oils (nuts for example). Often the oil that is used to roast things is soybean and this can lead to trans fat formations.

In regards to the question on soybean and corn oils, which are the most common (because they’re cheap) bulk cooking/baking oils used in about all junk food, etc…they are omega-6 oils - the “unhealthy polyunsaturated omega” due to its inflamation promoting qualities. Omega-3 does all the beneficial things in the body and omega-6 does all the non-beneficial things in the body. You need some omega-6 but the thing is, is that no matter what, with modern foods we eat way to much omega-6 and not enough omega-3. So you want to try and avoid the mass quantities of omega-6 (soybean and corn oils) found in junk foods and try to get more omega-3 (flax, fish and nuts). The other thing about soybean and corn oils is that as a omega-6 polyunsaturated oil, they are not very heat stable. And as such, when used in frying (it’s what is commonly used in the junk food manufacturing to deep fat fry chips and etc) or baking, the heat unstable omega-6 polyunsaturates (soybean and corn) have a tendency to particaially convert to trans isomers or transfats through the heating and oxidation processes. Hydrogenated and particially hydrogenated oils are the artificial man made transfats that are really bad but all the excessive omega-6 soybean and corn oils are unhealthy as well…especially if used in deep fat frying such as chips or party nuts, etc where some conversion to transfats occurs.

So dry-roasted peanuts would still be an OK source of fat?

Thanks for the responses, I guess I’ll have to throw away the rest of my can on Planters Cashews cause the ingredients list Cashews, Peanut and or Cottenseed Oil

In my opinion, if you are going to eat nuts, raw is best. Dry roasting may destroy some of the omega-3’s, but nuts are not super high in these fats anyway (walnuts are about 1/4 omega-3). Anything other than raw or dry roasted is not ok due to trans fat formations from frying the nuts in oil.