Nowadays, teenagers have changed in comparison with the teens in the past, taking into account eating habits, an active way of life, spending free time and clothes. They are a “technology” generation. For teens in todays’ world mobile phones, internet, music, movies, television and video games are very important. Most teenagers prefer watching TV and playing computer games to reading books. They don’t like reading because watching TV is easier and they don’t have to use their own imagination. Computer games teach but they are also harmful to health. Teenagers prefer to spend free time in front of a computer rather than to walk, play football or go to a swimming pool. Moreover, games transfer them into the world which doesn’t exist. It is very exciting for the youth. They meet with friends in such places as McDonalds. Teens eat there unhealthy food. They eat too much fast food. Every teenager needs a balanced diet, appropriate personal hygiene and physical activities in the fresh air, for example, playing a ball, going running, swimming, driving on the bicycle, playing in tennis or walking. This should be for them more interesting than sitting for hours in front of a computer or TV because such a mode of life leads to the improvement of mood, health and physical shape.. Young people choose less healthy kinds of entertainment than sport, putting away bicycles in the corner. They eat too much fast, unhealthy food, which is very fatty and drink too many sugary drinks. This leads to obesity. However, nowadays young people, especially girls, allow themselves to grow fat, or torture themselves with diets, which leads to various diseases with physical basis like anorexia and bulimia. Young people must not give up food, especially breakfasts because skipping breakfast is a frequent cause of fainting which can cause frequent complications and even leads to death. It