The average teenager in Singapore is a couch potato who loves junk food, but is level-headed about sex and smoking, according to a nationwide survey released Saturday.

The Health Promotion Board's survey polled 3,844 students from 51 secondary schools focusing on diet, exercise, sex and smoking. A mental health component is still under evaluation.

At least 70 per cent know about daily recommended intake of fruit and vegetables, but only 24 per cent follow the guidelines, according to the findings published in The Straits Times.

Exercise was not a top priority. Boys were more than twice as likely to exercise than girls.

Four per cent of the respondents said they have had sex and one-quarter of them had sex more than five times in the past month. Half of this group had sex before they were 15.
Only 2 per cent of teenagers are regular smokers. Half pick up the habit before the age of 12, and 19 per cent do not regard it as harmful.

Youth counsellor Carol Balhetchet told the newspaper the figure for sexually active teens appeared low compared with other surveys. But respondents may not have told the truth to avoid embarrassment, she said.

Nutritionist Anna Jacob said health is often not a priority among teenagers.

"They are in a critical stage of growth and burn calories like crazy," she was quoted as saying.

The sole result released for mental health found that most teenagers deal with stress by tuning out the world. They listen to music, watch television, play computer games and surf the internet rather than talking to someone about their feelings.