It's perfectly do- able to lose a lot of weight here....... Stage one will help you to get sick of eating junk and ready to move on, a preparation stage if you like, don't worry if you don't lose much then. Stage two is fasting all day...... You might struggle with this if your job is very physical, so you can graze a little if you need to . Your portion sizes will come down which will help with your weight too.
Keep posting with how you're getting on, and ask any questions if you get stuck

Welcome and good luck !