Context, Antonia, give us context! The expression is not familiar to me (your current book must be British.) A wild guess - something like margarine or mayonnaise that you spread on everything in your kitchen?
Cooking spread does mean margerine, as Khoff suggested.
He did well 'cos I was racking my brains for what 'kitchen spread' could be. There is no such phrase. It's a lot easier if you ask for a translation of the real words A!
Butter is definitely not low-fat. Margarine is not especially low-fat either, but they say it's better for the health than butter. Then you may have a third kind of cooking substance which is low-fat (I've seen some in my supermarket).
I've found it on the Internet: it's a kind of spread used for cooking and it's low-fat. I was confused because I never cook on butter or margarine, we almost always use olive oil. I don't see butter as kitchen/cooking spread. I eat butter with fresh bread and home-made jam. this is what comes to my mind when I hear butter, not cooking.