Once upon a time, foods that called for saturated fat were cooked with grass-fed animal lard, butter, and tallow. You might think those things are unhealthy, but they aren’t. What we replaced them with, are. 

Quick Chemistry Interlude:

Fats are made up primarily of carbon atoms bonded together. But each carbon can make four bonds. A saturated fat is one that is already bonded to as many hydrogens as it can hold. Like this.


An unsaturated fat is one that has space for more hydrogens. Like this.


Hydrogenation: Partially Hydrogenated Oils or Trans Fats

Then in 1907, Proctor & Gamble devised the process of hydrogenation of plant oils in order to render them solid at room temperatures. Hydrogenation means bombarding the unsaturated (liquid) fat with hydrogen ions to make it saturated.

But it doesn’t work so neatly as that. Instead of a fully saturated backbone, you tend to get trans fats, which have hydrogens on opposite sides of the carbon chain instead of on the same side. Like this.


This is bad because these fats won’t lay flat against each other, the way natural saturated fats do.  If these get into your cell membranes, it means signals don’t get in and out of the cells very efficiently. It also means nutrients and oxygen can’t get in easily, nor can metabolic waste get out. This matters, because toxic buildup is one of the primary causes for the inflammatory diseases of Western culture (such as diabetes, heart disease, autoimmune conditions, allergies, and cancer).

Interestingly these Western diseases began their steep ascent around the same time that Proctor and Gamble released Crisco (vegetable shortening), made from hydrogenated cottonseed oil. (Please note that cotton is not a food in the first place!) Crisco quickly replaced animal products such as lard, tallow, and butter in recipes that called for saturated fats.

These days, not too many people use Crisco anymore—but if you eat a Standard American Diet of processed and fast foods, you still consume plenty of trans fats. The high temperatures involved in frying foods in vegetable oil will create trans fats, and many of the processes involved in creating pre-packaged foods from vegetable oils (such as corn or canola oil, soybean oil, and cottonseed oil) will do the same.

The Take-Home Message:

  • Avoid fast and deep fried foods. They are usually fried in vegetable oil, and the heat will create trans fats because they are unstable at higher temperatures. This is especially true when the same vats of oil are used over and over again.
  • Avoid any prepackaged foods that say “partially hydrogenated” on the label.
  • Avoid Crisco or any other brand of vegetable shortening
  • Avoid anything made with cottonseed oil. Cotton is something you wear, not something you eat.
  • Avoid corn oil, canola oil, and soybean oil in general whenever possible. Aside from the trans-fat issue, corn and soy are almost universally genetically modified in the US anyway.

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