Yep. Maybe you could try some kind of a weekly checklist kind of thing? Like your weight and a bunch of yes no questions. So it takes like 1 minute.
I think you need to find a way to make it provide value on an on-going basis. Otherwise the utility of that app is pretty low.
Maybe you guys could find some way to bridge what "regular people" and "maniacs" like. Basically to somehow gather input from people that are wiling to do that without scaring regulars away. The data you gather could be the most valuable thing your company has.
We are looking for a way to do that but we haven't found any quick but accurate enough way to do that for the moment. I am confident we would find one day :)