Kids who carry excess weight may be doing permanent damage to their feet. When there is an increased amount of weight and stress being placed on the foot, it can cause significant changes in the foot structure. Children's feet aren't fully developed until the age of 14 or 15 for girls, 15 to 17 for boys, meaning their foot bones are easily mouldable. Also, as few as 15 to 20 extra pounds can contribute to the flattening of the arches and inflammation of the growth plate in the heel. This type of pain was seen only in very active children, but it is being seen increasingly in overweight kids too. It's difficult to determine whether children are obese because they have foot problems in the first place, which make it painful for them to be active, or whether the obesity is causing the changes in foot structure. Complicating matters is the fact that many children are born with foot deformities that can reduce their activity levels, such as flat feet or hammer toes. But it is clear that foot problems in obese kids can cause a vicious cycle, with the foot pain making it more difficult for them to be active, which makes it more difficult to trim down. Treatment of foot problems generally begins with conservative therapies such as custom-made shoe inserts, known as orthotics, and physical therapy. If such approaches don't work, surgery to correct the problem may be recommended.
American College of Foot and Ankle Surgeons,
January 2007