Saying American children are getting too sick and too fat, local doctors and organizers yesterday called on fast-food giant McDonald’s to stop marketing to children.

“Our playgrounds, private practices … are filled with children suffering from conditions related to their diet,” said Dr. Lisa Summers, a pediatric gastroenterologist at Children’s Hospital Boston. “Marketing can no longer be ignored as a significant part of this massive problem.”

The harsh words were directed to McDonald’s and a local franchise owner as part of a national effort to “retire Ronald McDonald.” Similar news conferences were held yesterday across the country ahead of the fast-food company’s shareholders meeting today.

Corporate Accountability International, the organization that is calling for the end to the marketing, tried the effort at the meeting last year.

This year the Boston-based organization took out advertisements in the form of open letters that appeared in newspapers in Chicago, San Francisco and in Metro.

The movement also comes when the company is using Ronald McDonald in a new series of commercials, reportedly calling on children to visit his website. The plan to put the clown mascot back on television was first reported earlier this year.

Those ads for “McDonald’s-style junk food” unfairly target children, especially those in disadvantaged communities, doctors said.

“Fast-food consumption is associated with obesity, and marketing drives consumption. McDonald’s is the pioneer in the field,” said Dr. Alan Meyers, a pediatrician at Boston Medical Center.