Tackling the nation's obesity epidemic will take time, at least a generation, said First Lady Michelle Obama. But there are small steps that parents, teachers, schools and corporations can do now to help deal with this crisis.

"You can make some significant improvement with small changes," Obama said.

In an online chat with Aol. Health, the first lady kicked off the revamped Let's Move site -- an initiative designed to help parents, schools and corporations work together to find a way to reduce childhood obesity.

As usual, Obama used examples from her own life to demonstrate the struggles that parents and children face. For example, she said that she and President Barack Obama have tried to do things such as making sure the girls fill up on water and get exercise with activities, such as dancing around the house.

They've tried to rid their home of processed food and limited television time. Obama said she can't tell her girls to eat all of her vegetables if she doesn't do the same.

"We are our children's best, first and often only role models, so we should make sure we are practicing what we preach," she said.

Childhood obesity is a nationwide epidemic but one that hits the African American community particularly hard.
About 11.9 percent of black girls are defined as extremely obese, and black kids are 1.3 times more likely to be obese than white children.

Obese children have high rates of diabetes as adults and a third of the children born after 2000 are expected to suffer from diabetes at some point in their lives.

Healthy eating and exercise are the best ways to change that. Healthy eating is about balance, Obama said. She cited her and President Obama's love of sweets and other treats and said she actually likes those things more.

"There's nothing wrong with having cake at birthday party or getting popcorn at the movies if you are eating healthy meals most of the time."

Parents and schools must understand that exercise is not an option but a necessity:

"We have to make sure school districts and parents understand that exercise is not an option. It's not an either-or situation."

In response to a viewer's question about where she hopes the initiative is in five years, Obama said she wants to see more coordination among schools and chefs to create healthier and tastier school lunches, more cooperation from corporate retailers in meeting healthy eating goals, and more education in schools about healthy food and exercise.