DES MOINES, Iowa (AP) — So many people are expected to join first lady Michelle Obama on Thursday for a "Let's Move" event in Des Moines that it might be difficult to move without bumping into someone.

The expected lineup will include Iowa Gov. Terry Branstad, Agriculture Secretary and former Gov. Tom Vilsack, gymnast Shawn Johnson, figure skater Michelle Kwan, NASCAR champion Carl Edwards, Iowa State basketball coach Fred Hoiberg and former WNBA star Tamika Catchings.

And 10,000 children.

"The whole arena will be performing and she's going to be participating," said Ruth Comer, a spokeswoman for Hy-Vee Inc., a grocery chain that has helped finance Iowa's Healthiest State initiative.

The public-private effort that drew the first lady to Iowa for events at Wells Fargo Arena.

The program is aimed at making Iowa the healthiest state by 2016 and includes a competition by cities to be deemed "blue zones" for healthy lifestyles. The 10 cities selected will be eligible for help in designing programs that help residents eat healthier and exercise.

Michelle Obama will make Des Moines her first stop on a three-day national trip to mark the second anniversary of her Let's Move initiative, which promotes physical fitness and healthy eating for children.

The Iowa effort is designed to help people improve their lives while also reducing health care costs that have increased in part due to rising rates of obesity.

Courtney Greene, a spokeswoman for Wellmark Blue Cross and Blue Shield, said the insurance company is helping to pay for the effort because it makes sense for individuals and companies. Wellmark has committed $5 million a year for five years, she said.

"If you want to improve employee health you've got to get to the root cause, and that's making the healthy decision the right decision and the easy decision," Greene said.

The Blue Zone concept was developed, in part, by the University of Minnesota School of Public Health. It was first tried in Albert Lea, Minn., and organizers said it led to lower health care costs.

Organizers will announce the first Iowa communities selected as Blue Zones in May.

At Thursday's event in Des Moines, the athletes will be joined by Bob Harper, the trainer on NBC's weight-loss program "The Biggest Loser" and the action will be backed up by dancers from the University of Northern Iowa.

The 10,000 children in grades six through nine will be bused in from 45 schools in the Des Moines area.

"It will be a real active time," said Comer, "There will be exercises, some dances and some movements."