I'd like to know what you're doing to "burn at least 600-1000
calories".
Fit factoid: Average
calories burned running a marathon: 2,624.
You would have to be running the equivalent of a half marathon every day to be burning 1000
calories.
As another poster pointed out, it appears you are over estimating.
That aside, what works in mathematics doesn't apply evenly to
weight loss.
There's just too many check and balances and different systems in the
body that don't know the first thing about math.
For an explanation why this is, try Googling something like "whoosh effect
weight loss".
Here's one link that gives an explanation Lyle McDonald wrote on the subject -
Explanation for the 'whoosh' effect
Essentially what he's *theorizing* is that
fat cells fill with water for a period and then your
body releases that water ("whoosh??") at a point and you see a decrease on the scale.
Not too sciencey, but seems to to be an explanation of what happens in real life.