How often do restaurants (non-fast food) use trans fat?

It used to be fairly common, but it's being phased out. Trans fats are good for deep-frying because they're stable at high temperatures. Plus, they're solid at room temperature, which makes them easier to handle. Oh, and they're cheap. read more

It's just not done anymore. All of this is to say, it is not something you really need to give any thought to with regards to restaurants. The places where trans-fats are still an issue is in processed foods. Many of these producers are having a hard time getting rid of trans-fats because they are inherent to the texture that their brand is known for. Recent FDA rulings will change that very quickly. read more

Since then, Massachusetts, Connecticut, California, New Hampshire, and New Jersey have also introduced bills to ban trans fats (often used for baking and frying) in restaurants. Some fast food restaurants, like Wendy's, are now using trans fat-free oil. read more

Last year, the Food and Drug Administration “declared war” on trans-fats, putting pressure on food manufacturers to phase out their use of the fat, and many are taking heed (for example, margarine and shortening used to be full of trans fats, but now the content is down to near-zero). read more