FORGET ABOUT BEING ON OR GOING ON A DIET
In order to successfully lose weight & keep it off you HAVE TO forget about being 'on a diet'.
Being 'on a diet' implies that at some point you will be 'off a diet' & that is one of the biggest reasons people are unable to stick with healthy eating and leading a healthier lifestyle to lose weight and keep it off forever.
The more you focus on being 'on a diet' the harder everything will seem, because even the thoughts that surround 'dieting' are negative & imply you will have to go without things you enjoy & exercise hard to shed those pounds.
Instead focus on creating a healthy style of eating & way of living that you can enjoy & therefore sustain. One that will promote weight loss, but without you having to eliminate all your favourite foods & drinks all the time. This 'style' will become your new habitual way of eating.
If you're not sure what this new healthy style of eating and living looks like, take some time to consider what you need to learn to be able to do this, think about areas where you may need some help and don't be afraid to ask for that help or where to find the information.
To help with this new 'mindset' it may also be better to approach your goals & targets in a different way. Obviously most people have an overall target weight, clothing size or fitness level that they would like to achieve & this is the ultimate goal, but it can be more successful to look at the way the goal is reached, in a slightly different way.
Rather than setting weekly or monthly targets for weight loss, try keeping your goals focused on the habits you want to change or develop which will get you to your ultimate goal.
So instead of having a goal to lose, say 5lb in the first month, you could set a Week 1 goal to complete a full week's menu plan of healthy meals & snacks in the right portions & stick to it. If that goes well, introduce another small goal in week 2, maybe something like adding 20 minutes of walking/running (or activity of your choice) 3 times during the week, as well as continuing with the success of week one with the menu plan. Write this exercise activity into your weekly plan so it's booked in for a time convenient to you - a fixed appointment.
Then carry on each week building in new small goals as you go and see what effect that has on your progress, rather than thinking about the number on the scales all the time. (make sure you take your measurements to compare to over time)
The reason this can work better, is because for some people, it can be really disheartening if a goal to lose 'X no of lbs' is not achieved. It can lead to feelings of failure, cause de-motivation & increase stress levels, which are all major barriers to staying on track.
Setting goals and targets this way can really help you to move away from the 'being on a diet' mindset & get into the 'creating a healthy style of eating' mindset.
The whole process is geared toward positive things to DO rather than negative things to try & stop doing.
Always focus on what you 'want' to be doing rather than what you don't want to be doing, because the more you think about what you are trying to stop doing, the more you actually focus on that, making it really hard to stop doing it!
Maybe this little explanation will help explain what I mean
If I tell you NOT to think about a pink elephant
You HAVE to think about a pink elephant
In order to be able to try and NOT think about a pink elephant
and the more you try NOT to think about that pink elephant, the more he pops into your head?
The same is true for food... the more you try not to think about it, the more you think about it
So focus on the foods you want to be eating and the habits you want to be doing only - and the other stuff will quite literally 'fall out of your mind' in time.
I hope this helps in some way.