This is probably the most common question I get asked whenever people come to know that I've quit all of my bad habits. Ironically, it's also the question I have no idea how to answer.
Here's the thing: I don't consider myself a very disciplined person.
Most think that you require a huge amount of willpower to resist urge after urge, but that's really not the case for me.
Well, discipline is built with consistent practice (doing things that are 'difficult', including cold showers, exercise, resisting urges to eat junk food, etc.) and although the initial stages of habit quitting definitely required me to become a more disciplined person, I now I understand that there is a way to ensure that cravings do not arise in the first place.
You do this by REFRAMING YOUR MINDSET.
People fail while on their diets because they still look at junk food as a reward.
Instead, what I did was I looked at junk food almost as if it was poison, and every time I'd eat it, I felt sort of disgusted at myself (don't take this too far though!)
In this way, the REWARD FEELING OF BAD HABITS DISSAPEARED for me.
And when there's no reward, there's no craving, and thus you do not need discipline, or any type of motivation, to be the healthiest and happiest version you can be.
I cover all of this in the MINDSET course in the classroom section.
Hope this helps.