Is hydrolyzed soy the same thing as partially hydrogenated soybean oil?
No; “hydrolyzed” means that a chemical compound is split into smaller units in the presence of water; for example, sucrose is split into glucose and fructose. It’s a benign process, even though it sounds similar to the “hydrogenation” we warn against. You’ll see it primarily referring to additives such as hydrolyzed soy protein, which are harmless and used in such small quantities that they are not a significant factor in your diet.
Hydrogenation is the addition of hydrogen atoms in place of the double bonds between carbon atoms in fat molecules. “Hydrogenated” or “fully hydrogenated” means all the double bonds have been replaced; “partially hydrogenated” means some, but not all have been replaced with added hydrogen atoms. Fully hydrogenated oils are solid at room temperature (like Crisco) while partially hydrogenated ones are softer. Many processed foods and margarines use partially hydrogenated oils. Which is worse? Fully hydrogenated vegetable oils resemble ordinary saturated fats, while partially hydrogenated oils have a chemical structure that is found nowhere in nature, so your body doesn’t know what to do with them. I avoid both types.
New US labeling laws requiring listing of trans fats have encouraged manufacturers to remove them from many products. Check the list of ingredients. Zero trans fats on the label does not always mean no trans fats.