Discipline is formed out of habits, habits can be good and habits can be bad. The good ones will lead you to become a better person, the bad ones lead to layiness.
Life’s too good to be wasted. So just don’t waste it. Discipline leads to a raised awareness. You need dicipline to change your eating and drinking habits.
You just need to start and not plan to start. When going into the kitchen waste a little more thought on what your going to eat. It helps in many regards. You don't have the right ingredients, well make a list and buy them at first occasion.
Those changes will make a difference after a short period of time. A week if sensitive more if not that much.
Many famous and succesfull people try to get a message thru: Just listen to them.
If you don't you better start, there is no other me available. There is so much you can change by picking up sports. It changes the way you carry yourself. Just as an example.
Discipline makes you reach more. Thus you gain a little awareness. Awareness is needed to deepen discipline. Discipline helps to save expenses, you see more and waste less. A good beginning.