I'm not sure about thw second question but this is PERFECT to help you keep track of how many calories, carbs, and fat you ate as well as how many calories you've burned and tells you how many calories you eat when you give it a specific time limit and you want to be this specific weight. The only bad thing is is that if you don't fill out breakfast lunch and dinner then it won't show you weight weight you should be in a month.
I've had good luck over the last year using the online and diet diary app. I know what I'm eating and it makes me think before eating. I actually reached the goal that I'd originally set - which was a good realistic goal. At that point I decided I want to loose more weight (to get down to really not overweight instead of just not obese). Not sure it will keep working, but so far so good.