How much weight would i lose per week if i eat 1200 calories of only protein shakes, fruits, vegetables, and?

yogurt? the protein powder i use is low carb with less than 5 grams of sugar. i'm also going to be exercising at least an hour a day, mainly cardio with some strength training too. anyways, how much weight do you think i'll lose the first week? i'm already a vegetarian so i don't eat any meat, so basically i'm just cutting out breads, pastas, cheeses, and sweets and i'm going to start exercising more. i'm planning on doing this for at least 2 weeks, and then maybe gradually adding in some whole grains.