If you go to a fast food restaurant, you will probably see a lot of teenagers. Today, many teenagers are overweight, and this is because of their bad eating habits. Most teenagers are fond of food with a lot of fat, oil, salt and sugar. People call this kind of food "junk food". But bad eating habits go beyond fast food. We find many teenagers eat unhealthily. Some don't have breakfast before they go to school. During the day, some don't have a proper meal for lunch. In a recent survey at one school, scientists found that over two thirds of the students didn't follow a healthy diet. They didn't like vegetables, and many of them didn't like to eat fruits. They preferred to eat food with a lot of salt, sugar, or fat. Parents today also worry about their children's diet. Some doctors give the following advice: Teenagers shouldn't eat too much junk food. Teenagers shouldn't eat food with too much salt. Salt can cause high blood pressure in the future. Teenagers should eat food without much fat, oil and sugar. Teenagers need to eat some fruits and vegetables every day. Fruits and vegetables are rich in vitamins and have little fat. Teenagers need to drink more milk. Milk will help their bones grow. Teenagers need to eat breakfast every day. It is good for their body and mind. The main purpose of the passage is to tell the children  _  .
how to keep a healthy diet to eat fruits and vegetables how to have a proper meal for lunch not to eat junk food