Here's some examples of a typical meal for me pre lap band:
EX1
1qt Beef Fried rice
10 chicken wings
2 egg rolls
2 cans soda
EX2
1 medium sausage, pepperoni and Canadian bacon pizza
5 bread sticks with 4oz of marinara
EX3
2/3 lb pasta
1 cup Alfredo sauce
1/2 lb chicken breast
3 slices garlic toast
Needless to say that was excessive with that Alfredo clocking in at over 3000 calories. I only really ate once per day, but it was still 3000 calories. So now that I haven't been getting very many calories in a day my weight has been plummeting. But that's going from 3000cal/day to almost nothing, so obviously the huge change will do that. For you, your body is used to weight watchers and has adjusted it's metabolism to receiving that 1200cal/day. You'll still lose the weight. Slowly, but it will go away. Just up your exercise and even 300cal per day will make a big difference in your weight loss plan.