The best strategy for achieving and maintaining a healthy weight in otherwise well teens is to eat a variety of foods, including fruits and vegetables, and get lots of exercise. Meeting with a nutritionist can be helpful. It is not just the quantity of food, but also the quality. Before the visit, it is often recommended that your daughter keep a record of everything she eats on three different days including at least one weekend day. She should be truthful so that the nutritionist can make specific recommendations based on her likes and dislikes.
Many suggestions about eating habits apply for the whole family and make it much easier for your daughter. For example, it is always wise to eat breakfast because when we skip meals, we run low on energy and tend to eat more at another meal. Likewise, healthy morning and afternoon snacks can keep appetites low and energy levels high. Limit juice, minimize sugar-containing soda, and consider a change from whole milk to low fat (1 or 2 percent). Drinking six to eight glasses of water a day may also help. Get regular exercise, both individually and as a family--after dinner walks, Sunday bike rides, or other activities. Limit television watching to one hour per day.
Be sure your daughter expects these changes to happen slowly, so that she can make them permanent. She should meet regularly with her doctor to monitor progress and give her support and guidance.