Just needs a little polish. Either the ability to add foods (kale, beef/chicken/vegetable broth, hot sauce, etc) or have a submission list. The whole "slide to add/check" could be replaced by a single tap instead. Other than that, I love it.
Oh and I'd pay up to $5 to get rid of the periodic ad that pops up, especially while actually shopping. Annoyingly tiny little X you have to tap whenever it shows up.