Like a lot of people I use MyFitnessPal to track my calorie intake and exercise. I've lost about 6kg since I started and it's helped get my BMI back into the green.
One of the things MFP does is give you a future weight projection at the end of each day (e.g. If every day were like this you'd weigh X in five weeks). This obviously rewards eating less than you burn, which is sort of fundamental to weigh loss.
Earlier on I accidentally completed an entry too early, before I had recorded everything I'd eaten. I got this warning:
This was really great to see. Rather than rewarding or praising people who are clearly not eating enough, the app warns them and provides simple, clear.
Apps like MFP are becoming central to so many people's lives, it's great to see them take the responsibility that comes with that seriously.