Predicting portion size is something we’re actively looking into. One of the reasons for getting Bitesnap out to a larger audience now is to be able to collect more training data for doing this. We’re also experimenting with allowing users to specify portion sizes in more natural units -- for example by comparing a serving to the size of their fist -- and we’ll automatically convert these to conventional units. Finally, we’re also building more tutorials and help content into the app to educate people on better estimating portion size (among other things).