Tescos (same stuff, made by the same company) Appleade has about 20 calories in a 2 litre bottle, so even if you drank 2 litres a day (after you got your water in) it isn't going to damage the weight loss process. I am sure it doesn't help abstinence and the discipline learning process though.
I only ever drink about 200mls at a time and even then, not everyday so it really isn't enough calories to fret about. I just finished a 2 litre bottle I bought 2 weeks ago so that says how little I drink of it. I mainly have it around for when I am in between shakes and need to "taste" something. Not ideal, I know, but if it stops me reaching for something more damaging I will live with it.