I was recently on vacation (to Singapore & Malaysia (beautiful countries)), and rarely had access to wifi, and using/buying mobile data would utterly break the bank. I was planning on counting calories, but I had totally forgot to check if the app works offline. It doesn't.
So I have returned with a feature request!
Please add the ability to use the app while without access to the glorious internet.
Let the app store data on my phone when offline, then the next time I am lucky enough to have a connection, sync whatever data I might have recorded, back into your servers :P