To lose one pound per week, an individual needs to reduce calories from their intake each day (either by eating less, exercising, or a combination of eating less and exercising).

500 Calories

Explanation:

One pound of fat is made up of 3,500 calories. To successfully lose such pound in a week, one needs to lose 500 calories every day by either exercising, eating less or a combination of both methods. If followed religiously for 7 days (a week) one would have successfully lost the 3,5000 calories that make up a pound of fat because 3,500 divided by 7 is 500 calories. 

500 to 1,000 Calories

Explanation:

To lose one pound per week, an individual needs to reduce 500 to 1,000 calories from their intake each day .

In order to reduce the intake of calories an individual needs to burn 3,500 calories to lose 1 pounds because 3,500 calories intake equal about 0.45 kilogram of fat.

Therefore if the person reduce about 500 to 1,000 calories a day from his or her diet, such person will eventually lose 1 pounds a week.

This can be achieved by eating 500 fewer calories per day either by eating less, exercising, or a combination of eating less and exercising which will equal 500 calories.

Therefore 500 calories burned in a day will lead to reduction of calories in the body.