You make thousands of choices everyday. You either choose to do something or you choose not to do something. Each of those choices are prompting your behaviors, good or bad.
Somewhere along the way a single choice can become a habit if the choice continues to be made and some choices require more willpower than others. For example, attending an early Sunday morning worship service may be a behavior that sits on the fence between being a choice and becoming a regular habit. For some the lack of willpower or enthusiasm will keep it on the choice side of the fence rather than forming a strong habit.
You can give up on a choice ever becoming a habit if it requires a lot of willpower, but you should be aware of what you are giving up. Placing yourself in a good environment on a regular basis may have more benefits than you are aware of. Using the Sunday morning example, by going regularly, you're triggering yourself not to stay up too late on Saturdays, not sleeping in on Sundays, and you're rubbing shoulders with people who in most cases want to be and do good in the world. It stretches you socially, spiritually, and perhaps intellectually. None of these things are bad, but to get the value each week you may need some willpower.
Remembering the "why" behind something that is difficult to do is key. If you can't come up with a good list of why's, then it may not be worth the effort. However, one of those why's ought to be considering what bad habits you might pick up if you weren't filling the space with a healthy, hard-to-do habit.
If you are struggling with a good choice becoming a habit, improve your odds by making an investment in your preparation. See if you can't make some smaller habits that help you rest and eat better in order to feed your willpower.
May you find the strength to choose good behaviors that turn into healthy habits.