According to the Mayo Clinic, all children need protein, fruits, vegetables, grains and dairy as part of their diet. Calorie requirements change with age, ranging from a low of 1,000 calories per day for a toddler or preschooler to up to 3,200 calories per day for a teenage boy. Helpguide.org points out that children should limit their intake of sugar and salt, choosing fresh foods over processed foods where possible.
Helpguide.org explains that toddlers and young children should eat two servings of protein per day, four servings of whole grains, two servings of fruits and vegetables and three servings of milk, which is the equivalent of one pint of milk per day.
School-age children need six to 11 servings of whole grains per day, two to three servings of protein and two to three servings of dairy products, according to Helpguide.org. In addition, they should eat three to five servings of vegetables and two to four servings of fruit. Children at this age need to make sure they are ingesting enough zinc, which helps with memory.
According to Helpguide.org, during the teenage years, children gain 20 percent of their adult height and 50 percent of their adult weight. This means they need a significant increase in calories, most of which should be eaten in the form of lean protein, low-fat dairy and whole grains. Teens need 45 to 60 grams of protein per day to help maintain muscle; vegetarians must pay special attention to this need and get protein from non-animal sources, such as soy foods, beans and nuts. In addition, teens often need additional calcium and iron.