Q: I understand how to identify trans fats as “partially hydrogenated.” But I sometimes see “fully hydrogenated” —for example, on Reduced Fat Jif Peanut Butter. Can you please explain what “fully hydrogenated” means and what, if any, impact it has on our health?
Answer : To understand the difference between “partially” and “fully hydrogenated” oils, you’ll need a short chemistry lesson—bear with us! In saturated fats, all the positions for hydrogen on the carbon atoms are filled. Monounsaturated fats have one pair of carbon atoms per chain that are connected to each other instead of to hydrogen atoms this carbon-carbon bond is thus “unsaturated”); so oleic acid, a monounsaturated fatty acid, which has 18 carbon atoms per chain, is