How fast will I lose?

I'm back at cutting down my intake to a very low amount of cals. 500 to 600 is the absolute max. I am training off about 800 cals by biking to work everyday. And I am running as often as possible, at least 5 times a week, which adds 300 burned cals to my daily usage of cals. About 1.000 cals is what my body needs for maintenance.

1.800 to 2.100 needed
600 cals consumed
= 1.200 to 1.500 negative calorie balance

How fast will I lose when I go on like this?