Relevant or Outdated? The 3,500 Calorie Weight Loss Rule

12 April 2016 In 1958, a now infamous study concluded one pound of body fat was equal to 3,500 calories. It's been conventional diet wisdom for over half a century: a 3,500 calorie increase or decrease, above or below maintenance levels results in a one pound change in weight. Most diets base their weight loss targets on this old rule: spread 3,500 calories over a week to see a gain or loss of one pound. Given the advances in our understanding of how the body works, does this 3,500 rule still stand today?