I don't know that foods have those kinds of healing powers yet in the game. There are herbal concoctions you can make by enhancing your herbalism skill.
Little Ms. Sam has some ways to make herbalism easier (or harder, depending on how you look at it)
http://littlemssam.de/tag/herbalism/
Bienchen also has helpful mods, but the site is in German. (google translate works okayyyyyyy, but you may be able to figure out the rest on your own)
http://www.deichschafblog.de/s4/bienchens-mods/
If you just want custom foods to make your game interesting, here are some links:
http://sims4studio.com/thread/2617/...&scrollTo=72754 - look for the crafting enabler to use Leniad's stuff
http://sims4studio.com/thread/6924/leniads-cupboard - read the info carefully - there are snippets you need, and spoils and no-spoils versions.
The fabulous Icemunmun has custom harvestables and craftables as well.
http://modthesims.info/m/4590936
Marion has some custom foods as well - read carefully as they require other scripts to show up
http://modthesims.info/m/7066489
Most of the custom foods are easy to use and install, but they require pieces to make them work correctly - so please read carefully before installing.
I hope this helps.