weightloss💪🏻✊🏻

I'm 5'2 and about 165-166 lbs if I went carb,dairy,and gluten free (paleo diet) for at least 3 weeks eating lots of fruits, veggies, and spinach with chicken for meals and lots of lemon water and gallon of water a day and at least a hour of excersize a day how much weight will I lose  in those 3 weeks ?? Looking for a fast fix with a lot of research I heard it works