According to the University of Maryland Medical Center (UMMC), trans fatty acids are also called hydrogenated fats. When you add hydrogen to liquid vegetable oil (a process called hydrogenation) and then add pressure, it results in a more solid fat, like what is found in a can of Crisco. Hydrogenated oil is found in a wide assortment of foods and is broken into two categories; fully hydrogenated and partially hydrogenated oil.
Health & Hydrogenated Oil
According to the National Institutes of Health (NIH), tran fats raise your LDL or "bad" cholesterol; levels and lower your HDL or good cholesterol levels. The Mayo Clinic says this combined effect increases your risk of heart disease, the number-one killer of men and women. The UMMC says public health experts warn that hydrogenated fats can cause clogged arteries and lead to obesity.
Hydrogenated vs. Partially Hydrogenated
The Mayo Clinic says you can determine whether food contains trans fats by looking for the term "partially hydrogenated" vegetable oil on nutrition labels. The Mayo Clinic says contrary to expectations, there are no trans fats in "completely" or "fully" hydrogenated oils. If a food label simply says "hydrogenated" vegetable oil, it's possible the product has some trans fat.
Deciphering Nutrition Labels
Some food manufacturers reportedly attempt to "hide" hydrogenated fats in nutrition label. According to the UMMC, one tactic consists of breaking up the components of the food (coating, filling). Such a detailed description can take up half of the ingredient listing, thus burying the second ingredient which is frequently hydrogenated fat. The UMMC says if hydrogenated oil is one of the first three or four ingredients listed, it probably means there is a large amount contained in the product and you should pass on it.
Fast Food Claims
The UMMC says it's also important to understand that when fast food restaurants proclaim that their food is cooked in vegetable oil, that can mean liquid or hydrogenated oil. When a fast food outlet says there is no cholesterol in its product because it contains only vegetable, that may be considered false advertising. The UMMC says vegetable oil can increase your cholesterol if it is a hydrogenated or partly hydrogenated vegetable oil.
Foods that Contain Hydrogenated Oils
The Mayo Clinic says since trans fats are more solid than oil, they help foods stay fresh longer. Among the food items that may contained hydrogenated or partially hydrogenated oil include commercial baked items (crackers, cakes, cookies) and fried foods (French fries, donuts).