Gaining weight when dieting?

I don't know how to add to my earlier question. For info my diet is 55% carb, 30% protein 15% fat. I use a cross trainer and jog, I'm 50 years old. I record my god and calorie intake as well as my exercise on an iPhone app.

I'm also losing trying to lose weight and I'm succeeding by doing the following;-

Eating low calorie meals, ie like weight watchers
Keeping my calories so that I eat no more than 1, 600 to 1, 700
and doing one hour of dance type aerobics 6 days a week, which burns roughly around 300 calories at my body weight (10 stone 12 lbs)
Drinking low calorie drinks, ie sugar free drinks
I also record everything I eat in a diary so I can keep track.

I suggest maybe looking at your calorie intake. Could it be that you are eating too many calories? Or maybe your not eating enough calories. Believe it or not, not eating enough calories can slow your metabolism down so that you end up gaining weight, or not losing any weight at all. It can make you hit a plateau.

Try to do about an hour of exercise per day, and give yourself one day a week off to give your body a rest.