Hi,
What I did was enter several days food into the app.
That gave me a baseline of what I had been doing.
Then I tweaked the ratios until I came up with a balance that I felt was sustainable.
One thing worth doing when you are dealing with my fitness pal - check that the foods you select from the database actually have the correct nutrients entered into them.
Most of the entries have been created by members of the public, and they often just put fat and calories into the fields. So make sure each entry you use has fat, protein and carbs entered - plus calories, if you want to track them too.
Hope that helps!