2800 calories is simply your intake. Anyone can force themselves to consume that much, whether they are Shaq, a smurf, or you. It's what you choose to eat, not at all what you're actually burning.
And you're on a malnutrition plan by starving your body of the nutrients it desires. I understand the desire to lose weight. I also share the same desire. Just make sure you take measures to prevent injury while starving your body.
If you with to simply maintain all your muscle mass without forcing your muscle to resort to feeding off internal energy stores, then you'll need around 6000 calories.
That said, it's VERY difficult to consume 6000 calories a day under any conditions. I've been working on shakes to allow me to down over 3000 calories a day without much effort. The rest would come from meals and snacks. Unfortunately these shakes are rather expensive, at least to me. Roughly $5 a day just for the shakes.