In today's marketplace, most consumers have learned to examine the nutrition labels on products before they buy. On the labels, you may see terms such as hydrogenated oils or _partially hydrogenated oil_s. Though similar in name, these two types of oil are very different. The process of creating partially hydrogenated oils produces trans fat, which experts caution against because of its negative health implications. It can raise your bad cholesterol (LDL) and lower your good cholesterol (HDL). In fact, it was recently banned by the FDA, and the date January 2020 was established as the date for final compliance with the ban. Trans fats became popular in the 1950s for two reasons: It extends food's shelf life; and it's cheaper than solid animal fats.

While small amounts of trans fats occur naturally in foods such as meat and dairy, most of it is found in processed foods. Fully hydrogenated oil contains very little trans fat, while the same can’t be said for partially hydrogenated oil. However, even though fully hydrogenated oils are better, they are still high in fat and should be enjoyed sparingly.

Fully Hydrogenated Oils

Peanut oil is also called groundnut or arachis oil. It's made from the edible seeds of the peanut plant, which grow underground, hence the term “groundnut.” Peanut oil is a source of unsaturated fat, and, depending on how it's processed, its flavor can range from sweet to strong to nutty. Peanut oil is available in refined, cold-pressed, gourmet or blended varieties. It’s often used in the preparation of Asian-style dishes and has a high smoke point, making it ideal for high heat cooking.

Corn oil is produced via a complex method that renders it into a refined vegetable oil. The kernels are pressed to separate the oil, and the oil then goes through additional processing to remove impurities, undesirable smells and tastes. Unfortunately, during that process, many of the naturally occurring vitamins and minerals are destroyed. If you’re concerned about genetically modified foods, keep in mind that most corn oil is considered a GMO food as a result of efforts to make the corn plant resistant to insects. Although corn oil is used in cooking applications that require high heat, such as deep frying and sauteing, it’s also found in liquid soaps, cleaners and lubricants.

Cottonseed oil is derived from the seeds of the cotton plant. It must be refined to remove the naturally occurring toxin, gossypol, which is responsible for its yellow color and to protect the plant from insects. While refined cottonseed oil is used for cooking, the unrefined version is sometimes used as a pesticide. Cottonseed oil works well in baked goods to make them moist and chewy.

Partially Hydrogenated Oils in Foods

Partially hydrogenated oil is often found in many food products, including margarine, premade baked goods (cookies, piecrusts and crackers) chips, fried foods, refrigerated dough, creamer and vegetable shortening. These types of products should be consumed as little as possible. Often, manufacturers substitute tropical oils, such as coconut, palm kernel and palm oils, but they are high in saturated fat, which can raise your body’s total cholesterol count. Check nutrition labels and choose foods that contain olive, peanut and canola oils; they contain monounsaturated fat, which is a healthier option.