There is at least one site on line that will give nutrition labels for different raw foods (even produce, and many specific brands of an ingredient) so if you want to get totally OCD about it (which I have done more than once because of how I log) you can go and add all of the info on each nutrient (fiber, protein, etc), add it all up, and enter that total in the label for your custom food.
As I said, it is a very OCD method, but more precise if you are using the same brand of ingredient each time you make the lunch. As for what to name the custom food if you have it on the same day you may call it "Monday's Lunch" or you can use numbers "Lunch Option 1".
The whole process is a bit cumbersome, but once it's done it will make logging infinitely easier. Good luck with your program.