As an example, she cited something she said she couldn't imagine when the "Let's Move" program was launched nearly four years ago: television commercials pitching fast-food breakfast sandwiches made with healthier egg whites instead of whole eggs.
But the first lady said more work is needed to solve the childhood obesity problem.
"Make no mistake about it, we are changing the conversation in this country," Mrs. Obama said at a back-to-school event at a District of Columbia elementary school. "We are creating a cultural shift in how we live and eat and our efforts are beginning to have a real impact on our children's lives."
"But I also want to be very clear. While we're finally beginning to make some progress, we still have a very long way to go before we solve this problem," she said.
In remarks to teachers, parents and others, Mrs. Obama cited documented declines in childhood obesity rates in New York City, Philadelphia, California and Mississippi. She highlighted changes to kids' menus by national restaurant chains and new labels at Wal-Mart stores that promote foods with less sugar, salt and fat.
Cities are building grocery stores in underserved neighborhoods and refurbishing playgrounds and bike paths for kids, Mrs. Obama said, and schools are planting vegetable gardens, installing salad bars and replacing food fryers with steamers.
But she urged audience members not to be complacent.
"Right now, we're truly at a pivotal moment, a tipping point when the message is just starting to break through," the first lady said. "And if we keep pushing forward we have the potential to transform the health of an entire generation of young people."
The event highlighted a part of "Let's Move" that encourages physical activity throughout the school day.
Mrs. Obama was joined by retired NBA center Shaquille O'Neal and two Olympians, sprinter Allyson Felix and gymnast Dominique Dawes. All four later changed into sweat clothes to run dozens of the elementary school pupils through a series of aerobic exercise drills.
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Uli Becker, president of the North American division of Reebok International, announced that BOKS, an initiative of Reebok and the Reebok Foundation that provides physical activity and nutrition before school, will provide 500 schools with grants of $1,000 each to adopt the program.
The consumer advocacy group Center for Science in the Public Interest criticized O'Neal's participation as inappropriate. O'Neal has a new line of cream sodas that the group says has 270 calories and 17 teaspoons of sugar in each 23-ounce can. The CSPI says sugary drinks are a leading cause of obesity.
O'Neal said it's up to schools and parents to keep children active and in shape, as he said his mother did with him.
"As parents, everything that we do for our children should be done in moderation," O'Neal said in an interview with The Associated Press after the event. "I don't drink my soda every day."
Let's Move Active Schools:
Press; By DARLENE SUPERVILLE]
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