Even after you delete foods from your favorites, you can still use them. Hit "Search" and right next to the Enter food not listed is a " more " button. Put cursor over it, and 4 options become available. Click " Search foods I've manually entered ", and then just type it in like a regular search. The only things that will pop up are the foods you manually entered that include those words. So you may get 3-4 options, and just pick it and use it for that day. You don't lose the info entered just because it is no longer on you favorites list.
Hope that helps. My favorites list is about 40 foods, but my foods that I manually entered is over 100. Most of it I don't eat weekly though.