How many calories usage to burn 1 pound fat?

food component	energy density
	kcal/g	kJ/g
fat	9	37
ethanol (alcohol)	7	29
proteins	4	17
carbohydrates	4	17
organic acids	3	13
polyols (sugar-free sweeteners)	2.4	10

Human fat tissue contains about 87% lipids, so that 1 kg of body-fat tissue has roughly the caloric energy of 870 g of pure fat, or 7800 kcal (9kcal/g x1000 x 0.87). Therefore one has to create a −7800 kcal deficit between energy intake and use to lose 1 kg of body-fat. In U.S. customary units, that is about 3500 kcal per pound. [2]