Are you fed up with losing weight and then putting it back on again?
Do you find it a struggle to maintain a healthy eating 'regime'?
That word - 'regime' - may be the culprit. It can have the same effect on you as the word 'routine'. These words suggest being hard on yourself. Making rules. Punishing yourself if you go 'off the rails'. It makes the whole business of getting to and maintaining a healthy weight seem like so much hard work. You can keep it up for a while, but then you just get exhausted!
And once you have fallen off, you are more likely to say to yourself, "What's the point? I'll never manage it!" And then you swing in the opposite direction and over-indulge yourself. Unfortunately, the consequences of that don't exactly make you happy either, do they?