Children as young as 2 years of age may be influenced in their food choices by a 30-second advertisement they see on television.

The investigators found that a group of children aged 2 to 6 years were more likely to choose food products that they saw advertised compared with youngsters who had not viewed the commercials.

In fact, just one or two commercials were enough to influence their choices.

Some researchers speculate that childhood obesity results from children spending more time watching television than in any other waking activity, thereby being exposed constantly to televised portrayals of high-fat, high-energy foods.

Parents need to understand the power of advertising on young children and limit the time they spend watching TV.

Kids are bombarded with the same commercial over and over again. But it doesn't take repeated exposure; the effect of advertising can happen from just a single exposure.

Advertisements for new products were particularly influential.

In other findings, nearly two thirds of parents reported that a television was on in their home most of the morning and 81% said it was on most of the evening. Children were more likely to watch TV if their parents did.

A growing body of evidence on the influence of TV viewing on children prompted Congress to pass a law in 1990 that limited commercials in children's programming to just over 10 minutes an hour on weekends and 12 minutes an hour during the week.

Journal of the American Dietetic Association January 2001; 101: 42-46