Overweight children and teenagers can easily tolerate a moderate reduction in calories in order to help maintain or lose weight. This usually means having slightly smaller-sized meals and cutting out high-fat, high-sugar snacks and drinks between meals.

Children should avoid crash and fad diets at all costs. Such inadequate food intake, even for short periods, may compromise their growth and development. Crash diets also encourage unhealthy attitudes towards food and a create a poor self-image; both are problematic and could lead to eating disorders.

Children and teens have greater nutritional needs than adults, and this needs to be kept in mind when a young person is losing weight. For example, for each 2lbs of body weight a 5-year-old child (about 36 lbs) needs twice as much protein, thiamin, vitamin A, vitamin B6, vitamin B12 and vitamin C as a 140 lb man.

The same 5-year-old child needs as much calcium and iron as a 25-year-old man. As the child's stomach capacity is much smaller than that of an adult, food eaten by children needs to be fairly dense in nutrients in order to obtain the full quota of required nutrients. Thus there is little room for “empty calories” or high-fat and high-sugar foods such as chocolate, soft drinks, candy, pies and cakes. Such foods fill the stomach and supply excessive calories without supplying the necessary nutrients.

Many overweight children and teenagers may not actually consume any more calories than their counterparts of a decade ago, but there is usually a dramatic difference in the amount of exercise these kids and teens get. The increasing popularity of computers, TV, and video games as daily pass-times means that many young people simply don't get enough physical activity to keep their body weight healthy.

Children and teenagers need to exercise for at least 30 minutes each day to maintain a healthy body. Exercise can take any form from organized activities such as cycling, walking, running, or training with a sports team, to casual play activity in the back yard, park, or playground.