The number of calories needed to maintain body weight depends on many factors, including gender, age, current weight and activity level. There are formulas and calculators online that can help determine the appropriate number of calories based on individual needs.
People looking to lose weight should be familiar with ratio of calories to body weight. It takes approximately 3,500 calories to gain or lose a pound of body weight. A person looking to lose weight needs to create a calorie deficiency in order to do so. For example, a person normally consuming a 2,500 calorie diet could restrict their calories by 500 each day to lose 1 pound per week.