Trans fats (partially hydrogenated oils).
These fats occur naturally in meat, but their main dietary source is packaged baked products such as cookies, cakes, breads, and crackers, as well as fast foods and some dairy products.
Trans fats were artificially created in the laboratory to provide cheap alternatives to butter.
Food chemists found that they could solidify vegetable oil by heating it in the presence of hydrogen.
As a result, the structure of polyunsaturated fat (a good fat) becomes more like saturated fat.
Thus, solid vegetable fats such as shortening and margarine came into being.
Today, trans fats are found not only in solid foods such as these, but also in foods that contain “partially hydrogenated oil.”
Trans fats are even worse for you than saturated fats.
Not only do they increase your LDL cholesterol, but they also reduce your beneficial HDL cholesterol.
There is no safe level of trans fats.

Companies like using trans fats in their foods because they’re easy to use, inexpensive to produce and last a long time.  Trans fats give foods a desirable taste and texture.  Many restaurants and fast-food outlets use trans fats to deep-fry foods because oils with trans fats can be used many times in commercial fryers.

Before 1990, very little was known about how trans fat can harm your health.  In the 1990s, research began identifying the adverse health effects of trans fats.

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