Human nature is to focus on a negative. Without intentional effort behind developing positive habits, we will develop bad habits naturally.
You can find this within your own thoughts and your inner dialogue.
A lot of people that set out to lose weight will say "No more candy" "no more pizza" "no more XYZ"
This is developing several bad habits in their mind.
Firstly, I believe there is benefit in thinking towards abundance. Rather than depriving yourself of something, focus on what you get to do. Rather than thinking you don't get the tasty sugary food, think about how you get to find a way to enjoy healthier foods.
Secondly, the brain will naturally become obsessed with what it thinks about. 90% of your thoughts every day, primarily subconscious thoughts, are all the same thoughts day after day. They're the habits, rhythms and routines your mind goes through to operate day to day. If you're constantly thinking about how you don't get to have a type of food, and you miss that type of food, and it would be great to get to the cheat day of having it, you're going to set yourself up for failure and eat the food because you'll become obsessed with it.
So look at the positives. Rather than taking something away from your life, add something to it that will create a positive change.
You can alter your articular reactivating system in your brain (those 90% of your thoughts) by reminding yourself to have the right thoughts about the right things several times a day, until it's a subconscious obsession.
You'll see examples of this at a simple, every day level. If you think about how you never see yellow cars, and you can't think of a recent example of a yellow car, I promise next time you're out driving you'll see a yellow car.
You can make your mind obsessed with the positive habits that will make you the person you want to be. It takes intentional, daily effort, to build the habit until it's on auto-pilot.