Trans fats are bad news. If your ingredient label lists partially hydrogenated oils, you know you’ve got trans fats. But what about fully hydrogenated oils? Or when an ingredient label lists partially hydrogenated oils but claims “trans fat free” on the front?
Let’s start with a little explanation on what hydrogenation is. Fats like butter and animal fat are solid at room temperature. Most oil is liquid, although some tropical oils like palm and coconut are semi-solid at room temperature. The more solid a fat or oil is at room temperature depends on the percentage of saturated fats. This is because saturated fats contain more hydrogen atoms than unsaturated fats which allow them to stiffen up.
If you’re a food company, you like saturated fats. They have a longer shelf life in baked goods and provide a more creamy mouth feel. The problem is that saturated fats are both expensive and feared. Cheap oils like soybean and cottonseed are liquid at room temperature, which poses a problem if you want to use them to make shelf stable items like cookies, cakes, and nut butters. So you hydrogenate them- blast the oil with hydrogen atoms until is becomes solid at room temperature, but still spread able. Hello margarine!
If you only partially hydrogenate them, you get trans-fatty acids (if you’re an organic chemistry fan, you’re changing the Cis confirmation to a Trans, hence the name) If you hydrogenate all the way, you get a saturated fat.
Although saturated fats are no angel, if seems that trans-fats cause serious health issues. Always check the label. If it says “partially hydrogenated fats” it contains trans fats. Companies can use the wording trans-fat free if it contains 0.5g or less of trans fats per serving. The daily maximum is 2g. So, if you’re eating 4 or 5 foods labeled trans fat free, but still contain partially hydrogenated oils, you’ve more than likely gone past your daily max.
What to do at the grocery store: Avoid products with partially hydrogenated oils, because of the trans fats. Limit products with high saturated fat values, whether naturally occurring or through full hydrogenation.
Which brings me to the age old question- butter or margarine? Neither. Try a spread like Earth Balance which is made from expeller pressing unsaturated oils.