The best food is the food you can get the most of! 20 minute crops are great for rapidly increasing your food supply. That's Corn, Pumpkins, Leeks... And you get more per harvest if your crops are watered and composted by harvest time. You can check out the Gardeners Guild if you need help with snacks, so Bigs and Tiny will mind your fields. :)
Fishing is a good place to start, too. Pay Koda and fish by hand, then take your fishy friends to Thumbs in the cooking profession to increase their stamina recovery. Raw meats heal less than cooked!
It is tough to support yourself solely on food you collect from running through Campaign, so you'll want to get your other professions up and running in the meantime. I can also send you some raw meat to get started with cooking. Good luck!
If you're at level 12 farming, I personally believe broccoli is the best crop to grow for energy. It grows fairly quickly, gives a decent yield once fully leveled, and 10 stamina. Cooked fish is the best recipe to cook. Another thing I do is buy all the food in the mole market every time I go, if that's something you can afford right now. Start investing in lots of wolves, level them up through campaign, and equip them with leveled companions. You can play with them periodically and get a good chunk of pebbles! And some companions reward food as well.