I'm a personal trainer here in NYC and have used this app a lot! I find this app really helps me stay accountable and helps me stay on track with my nutrition! As I used this app more and more I discovered some of its awesome features! My fav is the Macro pie chart (you can get to it at the bottom of your diary).
The app already pre-sets your percentage breakdown and as you get more educated on nutrition you can start to play with those percentages. In order for your body to function properly your carbs should be between 40-60% of your food intake of course you want keep your carbs down but if you deplete your body of the necessary carbs it will go into starvation mode (not good for the metabolism).
The best results I've seen so far using this apps has been through monitoring my Macro pie chart throughout the day and it helps me with my meal choices too! For example I usually try and keep to have balanced meals but in the mornings I tend to be more carb heavy... Not a prob for a snack I'll just have a protein shake or have more protein for lunch and cut down on the carbs (remember fruits count as carbs!) I've seen some amazing results in my body

try using this method for a week and see how it works for you!!!