How many calories make 1 lb?

Answer 1

It requires burning approximately 3500 calories to lose 1 pound of body fat.

This is not to say, however, that a 3500 calorie binge will gain 1 pound of body fat, nor that a 35-hour marathon will result in a permanent 1 pound loss.

Rather, this figure describes how small caloric intake/output imbalances add up to weight loss or weight gain over a long term.