I can only repeat what dee has said that's exactly what I have found,
Portion sizes are a big one- it's not complicated just don't over do it
I know this sounds daft but talk to yourself when you are choosing something to eat and really think about if before just diving in.... That will give you time and space to make a better decision.
I.e do you really want that chocolate cake or would a low fat chocolate mousse do the job just the same! (I promise it does). So substitute! When shopping also make low fat low carb choices etc .
On the occasion where you don't want to substitute... It's give and take .... You want the cake..... Get your backside out for a run or a swim .... That's the pay off and it balances out! I still have treats and take out but I also work damn hard to make sure I get rid of it.
If you can find an exercise you enjoy that will make it so much easier because you will want to do it! (I'm considering doing a Jodie marsh!) haha! that's all I have done I've replaced an addiction to food with an addiction to exercise!
These are just new rules we have to learn to live by, we all come from a background of having no rules regarding food where if we wanted it we had it..... And I think we can all agree it just doesn't work. In my opinion I have worked too hard to F**k this up now... I like how I look and how I feel and must admit I am scared of going backwards... But I like that the fear is keeping me in check!
One last thing if you learn the basics of good nutrition and don't devote every waking minute to thinking about food and planning your next meal and weighing portions and obsessing about it .... It all really just comes down to resetting good habits xxx