Learn To Stop Listening To Yourself and Start Talking To Yourself
When you have those thoughts like "My weight has always been a struggle" or "its so hard for me to eat healthy" or "I have a crazy sweet tooth", stop listening to those thoughts. Immediately replace them with more useful thoughts like "I eagerly fuel my body with healthy foods", "Healthy foods satisfy me and make me feel amazing", "every day I am leaner and stronger"
You don't have to let those old tapes play in your head. Replace them. Learn to stop listening to yourself and start talking to yourself.