How to loose weight 1st time?

After breaking my back 4 years ago and being limited to exercise (walking with crutches) iv gained to ME a massive 20kg i used to be 67kg. i am mentally depressed also do to my life changing disability and getting help for that but with weight gain also its making me even more depressed and worthless. So i have set a date for this Saturday to start my first ever diet. I am going to be trying out Arbonne feelfit protein shakes for breakfast and lunch and am looking around at recipies for my dinner. I am going to start my phyisio exercises again to get a bit energy burnt.
My biggest probelm is i get massive sugar cravings at around 3 and 9pm and would like sum sugestions on what i could try to prevent these from happening please.
TIA