how quickly will i lose weight if i ate this?

how long would it take to lose weight and get to a size 4-5 if i only ate this.. BREAKFAST -plain oatmeal or -boost protein shake(chocolate) LUNCH -little bag of carrots SNACK -apple or other fruit(grapes,orange,cherries,etc) DINNER -half of whatever my mom cooks i would only be drinking water and those 0 calorie sparkling waters what do you think id lose and how long would i have to eat like this to get down to a size 4-5? thanks :)