Miso Stew. It's easy to trigger and gives a lot of capacity EXP. Just make sure to set another food that triggers when your Eleth Mixer goes below 50% capacity so that you know that you need to refill it and you can get some EXP from it. I forgot the name of what I used for less than 50%, but it was a food that doubled SP and gave a fair amount of EXP.

https://docs.google.com/spreadsheet/lv?key=0ArlFQrhowhdZdFJkMEYza1p4cklUZUQ3bm10YWRWeHc&rm=full#gid=0