If youngsters hooked on fast food have greater chances of becoming overweight, then blame fast-food ads on TV which entice them in the first place.

`We know that children and adolescents are highly exposed to fast-food restaurant advertising, particularly on television,` said Auden C. McClure, assistant professor of paediatrics at the Children`s Hospital, Dartmouth, Dartmouth-Hitchcock Medical Centre in the US.

`This study links obesity in young people to familiarity with this advertising, suggesting that youth who are aware of and receptive to televised fast-food marketing may be at risk for health consequences,` added McClure.

Previous research has shown that watching TV is tied with obesity. McClure and her colleagues sought to determine whether recognition of fast-food ads on TV is linked with obesity in adolescents and young adults, according to a Children`s Hosptial statement.

The researchers surveyed a national sample of 3,342 youths aged 15 to 23 years. Participants were asked about their height, weight, age, gender, race, socioeconomic status, exercise, consumption of soda or sweet drinks, frequency of eating at quick-service restaurants, how many hours they watched TV each day, and whether they snacked while watching TV.

They also were shown 20 still images selected from TV ads for top quick-service restaurants that aired in the year before the survey. The images were digitally edited to remove the brands.

Results showed that about 18 percent of participants surveyed were overweight, and 15 percent were obese. The percentage of youths who were obese was significantly higher among those who recognized more ads than those who recognized few ads (17 percent vs. 8.3 percent).

Even after controlling for the variables listed above, youths who recognized many ads were more than twice as likely to be obese compared with those who recognized few ads.

These findings were presented n Sunday at the Paediatric Academic Societies (PAS) annual meeting in Boston, US.