Is there such thing as burning too many calories each day when fat loss is a goal?

My BMR is about 1,700, I'm guessing I consume 1,200-1,500 calories a day, and I burn anywhere between 700-900 calories at the gym each day.

Is there such thing as burning too many calories? Or is it always beneficial? For example, is having a net -800 calories each day going to produce better and faster results than having -300 calories each day?