The Center for Science in the Public Interest, which has sued several restaurant chains over the nutrition content of their food, is threatening legal action against McDonald's unless it stops using toys to market Happy Meals to children.

Saying McDonald’s toy-based marketing violates consumer protection laws in Massachusetts, Texas, New Jersey, California and the District of Columbia, CSPI said Tuesday it would seek an injunction to prevent McDonald's from continuing the practice. CSPI gave McDonald’s 30 days to seek a settlement before the advocacy group presses forward with its lawsuit.

William Whitman, vice president of communications for McDonald’s USA, defended the chain’s longtime practice of selling Happy Meals with toys, saying: “We are proud of our Happy Meal, which gives our customers wholesome food and toys of the highest quality and safety. Getting a toy is just one part of a fun, family experience at McDonald’s.”

In a letter addressed to McDonald's chief executive Jim Skinner and U.S. division president Jan Fields, CSPI litigation director Stephen Gardner said the chain's Happy Meal toys prey on vulnerable children and undermine the authority of parents who bear responsibility for feeding their children and educating them about proper nutrition.

“McDonald’s is deliberately marketing directly to unsuspecting little children by offering appealing toys — usually ones related to popular movies or television shows,” Gardner, CSPI’s wrote. “McDonald’s marketing has the effect of conscripting America’s children into an unpaid drone army of word-of-mouth marketers, causing them to nag their parents to bring them to McDonald’s.”

McDonald's spokesman Whitman said that the chain "is committed to a responsible approach to our menu" and that it has added healthful Happy Meal options over the years.

"We couldn’t disagree more with the misrepresentation of our food and marketing practices made by CSPI," he said. "Since 2006, we have been a part of the Council for Better Business Bureaus’ voluntary initiative to address the importance of children’s well-being. In the U.S., McDonald’s primarily advertises the four-piece Chicken McNuggets Happy Meal, which includes Apple Dippers, low-fat caramel dip and 1-percent low-fat white milk.”

CSPI countered with the argument that, while materials promoting Happy Meals that currently carry a “Shrek” theme indeed focus on Apple Dippers and milk, children who visit McDonald’s often end up eating foods that are much less nutritious for them.

The advocacy group recently conducted a test of 44 McDonald’s restaurants in 14 states and found that French fries were included in hamburger Happy Meals, without an employee asking if customers would like the side dish substituted, 93 percent of the time. The data are based off 75 total assessments — 41 Happy Meals purchased within the restaurants, 34 ordered at the drive-thru.

Also, while McDonald’s identifies 24 Happy Meal combinations on its website, CSPI noted, every one of those meals exceeds 430 calories, or one-third the recommended 1,300 total calories per day for children 4 to 8 years old. McDonald’s pledged in 2007 to advertise only Happy Meals containing 600 or fewer calories, highlighting most often a four-piece Chicken McNugget Happy Meal with Apple Dippers and milk.

“Happy Meals are right-sized for kids, a concept that has not changed since its introduction in 1979,” Whitman said. “We offer Chicken McNuggets made with all white meat, a small hamburger made from 100-percent USDA-inspected beef, a small drink, including 1-percent low-fat milk, and a choice of small fries or Apple Dippers. Happy Meals provide quality, safe food options and resonate with parents.”

He added that, since 2008, customers in the United States have purchased more than 100 million Happy Meals with Apple Dippers and that McDonald’s USA sold more than 31 million gallons of milk in 2009, more than triple the volume of milk sold since the chain repackaged milk in single-serving jugs in 2004.

CSPI's legal threat against McDonald's comes about two months after Santa Clara County, Calif., approved an ordinance that prohibited restaurants in unincorporated parts of the county from bundling toys with children's meals that don't meet certain nutritional guidelines.

The advocacy group has taken on the restaurant industry’s largest brands before, suing KFC for its use of partially hydrogenated oils during the campaign to rid restaurants of trans fats that many advocacy groups waged several years ago.

Like most restaurant companies, McDonald’s stressed that consumer choice plays a critical role in public health. Speaking at an educational session about menu labeling at the National Restaurant Association Show last month in Chicago, McDonald’s senior director of government relations, Bo Bryant, said the Oak Brook, Ill.-based chain sells more apples and salads than any other restaurant company in the world.

The company also has defended its mascot, Ronald McDonald, repeatedly against calls for his retirement brought forth by watchdog groups like Corporate Accountability International, which pressed Skinner at the company’s annual shareholder meeting last month to discontinue advertising with the clown.

CSPI gave McDonald’s 30 days to seek a settlement before the watchdog group presses forward with its intended lawsuit.

Contact Mark Brandau at mbrandau@nrn.com.