IDENTITY DRIVES BEHAVIOUR.
I am "BLANK", so I do what "BLANKERS" do.
Think about your many identities (Mom, Dad, CrossFitter, Skier, Biker, Workaholic, etc) and think about how those identities drive how you act, the things that you do, the decisions that you make, your automatic response to different situations.
If you want to stop drinking beer because it makes you feel like shit but you continue to identify as being a Beer Drinker, how will that affect your ability to stop drinking beer?
I will tell you right now, it will make it harder.
So how do you change that?
Well, it doesn't happen overnight, but if you can be consistent with creating new identity statements that align with new behaviours, those behaviours will be far more likely to stick in the long run.