Sounds excellent.
It would also be super useful for people with IBS/FODMAP like dietary issues.
It could show you what ingredients may be causing flare ups (fructans and galacto-oligosaccharides and polyols)
The main issue I see though is that if you're going to include processed foods, things will get complicated.
The names for various ingredients change in some countries ie: Sorbitol is also known as glucitol, D-Sorbitol, Sorbogem and Sorbo .
I use this example because Sorbitol is a sugar alcohol that affect FODMAP types.
You might do well having a chat with the Monash University, they have done a lot of work on this and have even published an app for people to check and see what sensitivities particular foods might have.