They require more fluids and protein and should not be placed on fat-restricted diets. After the first year, children's growth rate and appetite slow. Instead, growth occurs in small spurts, paralleled by increased appetites. By age 2, children eat diets consisting of the basic food groups and by age 3, their eating habits are similar to their parents. Inactivity and eating non-nutritious snacks contribute to obesity in children.
Obesity is the most common nutritional disorder in children and often leads to obesity in adulthood.
In school-age children, undernutrition is the leading cause of growth retardation. Nearing the end of the primary school years, a second rapid growth phase occurs, marking puberty. Here, long bones grow rapidly, sex characteristics develop and fat and muscle mass increase. Boys and girls vary in their proportion of fat and muscle mass. Due to rapid growth of teenagers, eating habits reflect their increased energy needs.