The easiest way to make a healthy choice stick is to make it a habit. Habits are easy because, by definition, you do them consistently and without thinking about it. And since I brought up definitions, here's another habit specific: nowhere in the definition does it say that a habit must be a bad thing.
In fact, a lot of yours aren't. You brush your teeth in the morning out of habit. You hang up your coat when you walk in the door because of habit. You wash your hands after using the bathroom because it's a habit. All great things.
We are not born with habits. We create them.
Good and bad, they are our habits because we made them. We are influenced by others, our parents for example, but it is our own repetitive actions that create a habit. Give yourself a hand, you are super powerful.
Now that you know you are so powerful, use that power to create new, positive habits that will help you reach your goals.
Form a healthy habit, make a lasting change.
Choose a healthy habit that supports your goals. For example: "I will not eat sweets after dinner at home because I'd like to lose 5 pounds".
Cut out sweets after dinner when at home = HABIT
Lose 5 Pounds = GOAL
This is a great choice, because this desired habit, is SMART. It is:
You've defined the parameters. You know WHO will (not) be doing this, WHAT you will (not) be eating, WHEN you will (not) be doing it, and WHERE you will (not) be doing it. You've also defined WHY (your goal).
You can track your progress. If you eat a sweet at home after dinner, you haven't made progress that day.
You've just had dinner, so you aren't eating sweets because you are starving. You can get rid of all temptation. This is totally achievable.
You want to lose 5 pounds. You know that you can't "lose 5 pounds after dinner at home" but you can certainly create a habit, like cutting out sweets, to get you there.
This is a habit that you will focus on after dinner. You aren't cutting out sweets all day, all week, or forever. That would be an almost unachievable habit to form and you would be setting yourself up for failure. Instead, you will create this habit at one, specified time every day. When you go to bed without raiding the fridge for a cookie or a brownie, you have achieved success.
Attach your healthy habit to a prompt.
Your prompt should be a real action that you take, not a note written on your calendar or a picture of your dream body on the fridge (although you can do that too).
When you feel the impulse to grab a brownie after dinner, make tea instead, grab your book and hop in the bath. Do this every time you have the impulse to grab a sweet.
Form a different, HEALTHY habit instead of the unhealthy one you've become used to.
Again, this is SMART. You know exactly what you will do and when you will do it. You can track your progress - every time you take a bath instead of having a sweet, you've succeeded. It's achievable, it's relevant (tea, a bath and a book are all healthy habits that are great to make), and it's time-bound.
Celebrate each success.
Each time you take a bath instead of eating ice cream, you've chosen the healthy habit. That means that every, single, day, you succeed.
That is motivation in itself. It's hard to stay motivated to lose 5 pounds if the scale doesn't drop each day. That's why your goal is the WHY and your habit is everything else. You know that this habit will help you lose 5 pounds, so you can and should pat yourself on the back when you succeed each night.
Make a conscious effort until the day you forget to think about it, and yet you still take a bath.
It seems wild now to not have a sweet. That's insane, you think, that's my thing! What's insane is that you haven't stopped to think about how irrelevant that sweet is to your life. It doesn't have meaning. It's simply a habit. And at this point, it's not even making you happy!
There was a time in your life when you couldn't imagine going to a job every day, or having kids, or taking yoga 3 times a week. Now you can't imagine life without those things.
It doesn't take as long as you might think.
You have the power to create a habit. It's one of the only powers you've been practicing since childhood. Now, use it.