As far as the third one is concerned, there are many apps that do that already for the iPhone. E.g. Lose it! (http://itunes.apple.com/us/app/lose-it/id297368629

As far as the third one is concerned, there are many apps that do that already for the iPhone. E.g. Lose it! (http://itunes.apple.com/us/app/lose-it/id297368629?mt=8 http://itunes.apple.com/us/app/lose-it/id297368629?mt=8) which comes with a big database of food with nutritional info, preprocessed meal from brand names… It's well done, but it gets pretty cumbersome to enter what you ate.