I believe you would need to put them into a particular day, unless you are just referring to making custom foods. If you make a custom food, you can just click on "create this food" but not "add to food log" and it saves it.
"If you drop an egg, you don't say, 'Oh, shoot' and drop the other 11, do you?"
-Source unknown, but obviously brilliant
Reached goal 4/16/2010...but kind of afraid to look these days