I used it for a while. It does not work if you put your exercise into it. The website overestimates how many calories you burn in physical activity and if you put them into the app you end up being allowed to eat way to much. Not to say that exercise shouldn't be a part of your weight loss routine. It will boost your weight loss results a lot! But just use the app for counting calories not for logging workouts.
I have the app. I DID have to tell my daughter that she could not add any 'exercises' to the exercise log that were part of her daily lifestyle. For instance, I am a housekeeper, and I selected a moderately active lifestyle. So if I put in 4 hours of housekeeping as an exercise, my calories burned would be overestimated because that housekeeping is my lifestyle, make sense? If the only activity you do daily is your 3 mile run, but you choose a moderately active lifestyle because of that, and the rest of the day you sit in front of a desk, then counting that activity as exercise will exaggerate the number of calories you can have and still lose weight.