The thing is that if you drastically lower your calorie intake, eventually you will lose weight; that's why people die of starvation. BUT, for the short term, I find that I lose more quickly if I keep my calorie intake up around 1500 a day.

And anyway, Dr. A is not talking about just 1000 calories, he is talking about a fat fast, which is 90% fat. That's different than what most of us would be eating at 1000 cals a day.