Her daughters were 6 and 9, and Michelle Obama was like any other working mom — struggling to juggle office hours, school pick-ups and mealtimes. By the end of the day, she was often too tired to make dinner, so she did what was easy: She ordered takeout or went to the drive-through.

She thought the girls were eating reasonably well — until her pediatrician in Chicago told her he didn’t like the weight fluctuations he was seeing.

“I was shocked because my kids looked perfectly fine to me,” Obama says. “But I had a wake-up call.” Like many parents, however, “I didn’t know what to do.”

Today, the self-described “mom in chief” is launching Let’s Move, a campaign to help other parents deal with a national health crisis she describes in epic terms.

The goal: to eliminate childhood obesity in a generation.

“It’s an ambitious goal, but we don’t have time to wait,” the first lady said in an interview with USA TODAY in her spacious office in the East Wing of the White House. “We’ve got to stop citing statistics and wringing our hands and feeling guilty, and get going on this issue.”