Weight loss simulator

http://www.pbrc.edu/the-research/tools/weight-loss-predictor/ is somewhat simpler / less sophisticated than Hall's model.

It shows how a 500 calorie initial deficit, the one that is supposed to be 1 lb/week of weight loss, gives a loss of 2.9 lbs in the first month, 2.4 in the second, 2 in the third etc etc.

Explains its math at http://www.pbrc.edu/the-research/tools/weight-loss-predictor/about/

Enjoy.