1200 is minimum. Don't eat any less than that, EVER. And if you are on 1200, you NEED to eat your cals back from any exercise.
If you are going along fine, counting EVERYTHING properly, and still losing (yes half a pound a week is slow, but its still losing and still managable) its all good.
If not you can try a few things:
- eat a clean diet, cut out processed crap, and salt.
- eat more protein, less carbs, and a moderate amount of fat.
- drink lots of water - dehydration leads to water retention
- eat small more often or change the ratio... if you have the typical breakfast:lunch:dinner 1:2:3 ratio, then change it around, eat more in the morning or at lunch.
- don't eat the same kind of food day in day out.
- ALWAYS eat back your exercise calories.
- exercise more - get a good training plan - more lean muscle mass means your basal metabolic rate will be much much higher and will make it easier in the long run to lose fat.
Now this comes with a caution, as its not always a success with everyone, but its worth a try if you are desperate. The thing with people on a smaller number of calories per day is that their metabolism often starts to drop after consistently eating 1200 calories. Your body isn't designed to survive on weightloss calories long term and can crash to help cope with the lack of food... i dislike the "starvation" theory thats bandied about an awful lot, but its a similar theory.
What I find is that sometimes your body needs an increase every now and then. for 1200rs - saying you weigh in in the morning; that day of your weigh in - have maybe 1400 calories. Then go back to 1200 for the week. Honestly 200, even 300 calories over the week will not have you automatically put on weight. Don't be scared of a few extra calories! If you are on -1lb a week loss rate, it would take 3500 for you to maintain, so still well under that. I've come across cynics of this method but I personally find it to be the best, and most effective way of getting out of a rut/plateau.
HTH