Hi Natalie and welcome.
Coke zero is a good substitute.
If you are going to cut out carbs cut out the white stuff and go wholemeal... bread, rice, pasta and mountain bread. Carbs is actually the fuel that our body needs during exercise.
I only have wholemeal bread etc and dont ave carbs after lunch time...
I started the year at 109 kgs and am currently in the low 80's.
The trick is to find what works for you, take bits of advice from hear and there and make your own weight loss formula.
We are here to support you all the way matey!!