Don't do this to yourself. Eat properly, at proper times. Eat more than the measly 1000-1200 cals you are eating. You can't keep that up. You will just lose weight, then put it back on as your resolve dwindles and your hunger kicks in. And then you will feel bad.
Instead:
Work out how many calories your body needs in a day.
As a woman this is your weight in kilos multiplied by 0.9. Then multiply that figure by 24. Then multiply that 0.2 - 0.5 depending on how active you are. So 0.2 if sedentary, 0.5 if active.
To lose weight you need to have a calorie deficit of 3500 to lose a pound. So work out how much less to eat per day, or decide to burn some of it off with exercise, your call. Don't believe how much exercise machines say you burnt off. They lie, check out a good website and be honest with yourself about how hard you worked. Dont set too hard a target, even if you stick with it for a few weeks, being under by 500, 800 calories a day makes your body fantasize about all the quick and easy ways to get those calories back.
Divide your calorie intake up over the day in a way that means you are eating roughly every 3 hours. Only weigh yourself once a week at most, ideally first thing in the morning.
Thats it, thats all there is to it. Obviously proper food will help you make the most of your daily calories and junk wont.
All those diet books, GI-this, low fat-that, are just variations on how you create a calorie deficit without feeling too shitty. The truth is you will feel shitty if you have too much of a calorie deficit and eventually you will crack and binge and undo all your good work. Dont be a mug, be patient, be clever, dont fall for this quick diet nonsense. You need to put less calories in than you burn off. Basta.
Also
Set some realistic goals and when you get there celebrate with something that isn't food.
PS: a realistic goal is one that's in your control. So say to yourself my goal is to exercise x amounts of times per week for x number of weeks. And when you achieve that you celebrate. Or I will drink 2 litres a day for 4 weeks or whatever. Dont make it a goal you have little control over like 'I will weigh X'.
If this doesn't work have a look at your self, your life and your friends and see who wants you fat. Maybe its you. Being fat is cosy, its friendly, gets you sympathy and lets you dodge tricky issues. Figure it out and you can work on getting thin. Otherwise decide to stay fat and enjoy it. Or even realise that you are fine as you are. Who knows? But this thing you are doing now is a waste of time.