My gf has lots of problems with various foods and manages to keep on top of it fairly well - although she has very little concrete evidence about what it actually is that is causing the problems.

I could see her trialling a comprehensive ($30 a week) package for a few weeks, then dropping to a less intensive (~$10 a week) package that kept her on the right track.

I personally don't think she would pay $30 a week unless the service gave her a significant material difference in lifestyle (which I certainly imagine it could have the potential to do).