I heard you should eat 1, 200 calories a day, and - 500 calories a day to lose weight. is it ok to eat 700 calories a day for 2 weeks ? to jump start.

Yes, but: There is no harm to restricting your calories for a two week period as long as you are getting sufficient nutrients. Make sure you are getting the essential vitamins, minerals, fatty and Amino Acids and drinking at least several glasses of water to keep your urine from being dark yellow. However, when your body gets such little food consistently, your metabolism will slow down.