In an interview, Dr. Hall said the longstanding assumption that cutting 3,500 calories will produce a one-pound weight loss indefinitely is inaccurate and can produce discouraging results. A more realistic result, he said, is that cutting out 250 calories a day — the amount in a small bar of chocolate or half a cup of premium ice cream — would lead to a weight loss of about 25 pounds over three years, with half that loss occurring the first year. Dr. Hall noted that typical weight-loss programs result in significant losses over a period of six to eight months, followed by gradual weight regain in the years that follow.
Dr. Hall and his colleagues wrote that “all reduced-energy diets have a similar effect on body-fat loss in the short run” and that “some diets can lead to reduced hunger, improved satiety, and better overall diet adherence during a weight management intervention.”