Jodi Evans is a national advocate for children.

And she’s just a child herself.

Jodi, 11, a sixth-grader at Robert Goddard French Immersion School in Prince George’s County, was recently selected to serve as a youth ambassador on the Alliance for a Healthier Generation’s youth advisory board. It will be her third year serving on the board.

As a board member, Jodi acts as a spokeswoman for the alliance, meeting with officials and students to talk about making healthy choices. She also is charged with finding ways to make members of her school and community healthier and with working to implement those plans.

In the past two years, she has held “Fun Run and Walk for Kids,” a neighborhood run/walk event in Bowie; created a kids’ fitness group, “KidsBeingFit”; and spoken passionately about childhood obesity and health choices.

According to the Centers for Disease Control and Prevention, more than one-third of children and adolescents were overweight or obese in 2012, the most recent figures available.

The percentage of children between the ages of 6 and 11 in the United States who were obese increased from 7 percent in 1980 to nearly 18 percent in 2012. Meanwhile, the percentage of adolescents between the ages of 12 and 19 who were obese increased from 5 percent to nearly 21 percent over the same period.

“The healthy habits we maintain today can become the healthy habits we maintain as adults,” said Jodi, who wants to become a doctor.

Jodi said she thinks that her efforts have already had an impact and that her classmates at Robert Goddard have made healthier choices.

“They think that it’s important,” she said.

Howell Wechsler, chief executive of the Alliance for a Healthier Generation, said Jodi is one of 20 youth ambassadors from across the country serving on the board.

He said Jodi, who was the youngest member of the board when she joined three years ago, returns to the position because of her “commitment to health and wellness in the Bowie community, helping to reverse the nation’s childhood obesity epidemic.”

As a youth ambassador, Jodi will spread the message of the alliance to promote healthy habits among young people. The alliance was founded by the American Heart Association and the Clinton Foundation.