Youth fitness is a huge health problem because research has shown that eating habits and propensities toward obesity start in earliest childhood. So it is commendable that President Bush has lent the weight of his office to a public service campaign involving Hollywood, Madison Avenue and the fast- and packaged- food industries.

"One way for this nation to cope with the issue of obesity is to get people outside - - whether it be through sports or hiking or conservation, " Bush said.. "So we'll encourage them to do that, encourage parents to encourage their children to participate in the great outdoors."

Using Shrek characters to tout healthy habits may be entertaining, and asking Kraft Foods, Coca- Cola and McDonald's to send healthy messages in their advertising may make people feel good.

But asking parents to send their kids outside to play more is risking even worse outcomes than obesity if they live in unsafe neighborhoods or areas without sidewalks and playgrounds. At the other end of the age spectrum, a recent study showed that conditions amenable to walking are linked to - - more walking!

Reaching a tipping point in the fight against obesity and fitness will take much more than hectoring and presidential statements. It will take better parenting but also better land use planning, transparent food labeling and perhaps regulation of television advertising to children.