Children in the United States eat too much pizza that some researchers now argue the food should join the ranks of sugary drinks and fast food for the harm they do to health. In a new study, the researchers found that pizza is a large source of calories, saturated fat and salt in children's diets.Children should not eat more than two slices of pizza for a meal,and should pair that with salad, rather than with another high-calorie food,the researchers concluded. "Parents should aim to control pizza consumption , particularly as a snack where it was shown to have a very adverse impact on children, and they should put their pizza dollars toward healthier brands."Said Lisa Powel, director of the Illinois Prevention Research Center. Pizza has become a matter of focus in recent years for researchers who look at the meals children eat, rather than the nutrients within them.Studies have found pizza is among the greatest sources of calories for children. "Since pizza remains a common part of children's diet, we need to make 'healthy' pizza."Powel said.To make pizza healthier, food producers should reduce its saturated fat and salt, and increase its whole grain content," she said. Whether or not pizza is harmful enough to be picked out as an unhealthy food, the study attracts attention to a larger issue with the modern American lifestyle, said Alexis Tindall, who was not involved in the flow research. "Many foods are eaten too frequently and in large sizes," said Tindall.To solve the problem, people don't have to give up eating pizza, but instead, they can eat smaller and healthier pizza,"she said. "Make it at home, instead of ordering it out where you don't have any control over how it's made." Tindall said. "When we make it at home, we can choose healthier ingredients,increase the vegetables, reduce fat, and put in less cheese.Pizza doesn't have to be just pepperoni and cheese." The last sentence of the passage implies that pepperoni and cheese  _  .
are necessary ingredients of pizza are not the only healthy ingredients of pizza should all be replaced with healthier ingredient. should be reduced by adding healthier ingredients.