A pervasive dieting mantra is that a cumulative reduction of caloric intake of 3,500 will result in a weight loss of 1 pound. This dieting rule popularly states “because 3,500 calories equals about 1 pound (0.45 kilogram) of fat, if you cut 500 calories from your diet each day, or burn 500 calories extra per day from exercising (or a combination thereof) you’d lose about 1 pound a week (500 calories x 7 days = 3,500 calories) and 52 pounds in a year.
This simple weight loss rule continues to be cited on weight loss websites as well as authoritative nutrition textbooks [1, 2], scientific articles [3-6], and expert guidelines. It is even common among health care professionals to believe in the 3,500 calorie rule , and the Patient Page on “Healthy weight loss” at The Journal of the American Medical Association website states in the first sentence on “What you need to know about weight loss” that… “A total of 3,500 calories equals 1 pound of body weight. This means if you decrease (or increase) your intake by 500 calories daily, you will lose (or gain) 1 pound per week (500 calories per day × 7 days = 3,500 calories).” 
However, is this really true? Most people who have ever been on a diet are probably skeptical. And rightly so. In this article I will highlight what’s wrong with the 3,500 calorie rule and present a more accurate calculator that you can use to more precisely predict how much weight loss you can except in real life from a given daily calorie reduction.