Even some severely obese preteens should be considered for weight loss surgery, according to new recommendations.

The guidance issued Sunday by the American Academy of Pediatrics is based on a review of medical evidence, including several studies showing that surgery in teens can result in marked weight loss lasting at least several years, with few complications. In many cases, related health problems including diabetes and high blood pressure vanished after surgery.

While most of those studies involved teens, one included children younger than 12 and found no ill effects on growth, the policy...