A person must burn approximately 49,000 calories in order to lose one stone, or 14 pounds. That figure is according to Mayo Clinic's calculation that each pound lost is about equal to 3,500 calories burnt.
Losing one stone of weight requires a deficit of 49,000 calories, which means that a person must burn 49,000 more calories than she consumes over the same period of time. The calorie deficit can be achieved through any combination of decreased intake and increased energy exertion from additional exercise, says Weight Loss Resources. For example, a person can reduce her intake by 300 calories per day while increasing the amount of calories she burns per day by 200 calories to achieve one pound of weight loss per week, or 500 calories per day. According to the Mayo Clinic, the weight loss method used determines which portion of the lost weight comes from fat, lean muscle or water.