I'm with SuKi. In the U.S., we use "packaged" as the adjective that describes anything that has been put into some type of wrapper/container: packaged food is the prime example, but packaged ingredients, packaged goods, even packaged facts (to refer to a selected group of information) "Packed" as an adjective usually means that something is filled to overflowing or tightly compressed: that room is packed with people. The dirt is packed down in that hole.

I don't know where you've got this distinction from, but I don't think it's right. As far as I know, 'packaged food' is used in both the UK and the US. 'Packed' food doesn't really mean much, unless it's the food that you've packed in your backpack to take hiking, for example.

I cannot speak for British language usage, but as a native American, "packed" and "packaged" have two different meanings for me. "Packed" is the past tense of the verb "pack", although it can also be used as an adjective, as in "packed [noun]". That noun could be anything that can be packed (including food). However, "packed food" does not make me think of commercially prepared food, as does "packaged food". Instead it makes me think of food that someone packed into a certain space or container. Example: When we went camping our packed food included lots of healthy snacks, some commercially packaged and some packed into our own containers. "Packaged food", in my mind nearly always refers to commercially prepared food. These kinds of food would be sold in packages designed to give them the best shelf life.

i agree with Larry. packaged is more about a commercial sense.

Although people in England have somewhat different names for things. ( yard, garden) ( trunk, boot). Packaged food means the same thing; food that is put in a package. " A packet of crisps" in England is a " Bag of chips" in America. Packed is the past tense of " pack". If you have " packed" something, you have already done so in the past.