(Apologies if you're an OCR guru and this is a stupid comment, but...) I wonder if it would be easier to get an MVP together using Amazon Mechanical Turk. A quick Google search reveals that there are lots of commercial products providing OCR on nutrition labels, but getting open source OCR to work reliably with phone-quality images (poor lighting, curvature of containers, etc) is tricky.
Either way, I think OCR-as-a-service would be really useful, and nutrition labels are probably a great place to start. I think there's lots of room for improvement in the nutrition/meal planning space.
I know FoodEssentials used to do this on mTurk. I did them myself on that platform. They haven't been around in a while, though. I'd be more than happy to enter nutritional label information on mTurk should that method be chosen.
Either way, I think OCR-as-a-service would be really useful, and nutrition labels are probably a great place to start. I think there's lots of room for improvement in the nutrition/meal planning space.