NEW YORK (CNNMoney.com) -- A nutrition watchdog group is threatening to sue McDonald's if the fast-food giant won't stop using toys to to lure children to its Happy Meals .
The Center for Science in the Public Interest said Tuesday that it has served McDonald's notice of its intent to sue over what it says is unfair and deceptive marketing.
"McDonald's is the stranger in the playground handing out candy to children," CSPI's litigation director, Stephen Gardner, said in a prepared statement. "It's a creepy and predatory practice that warrants an injunction."
In its notice letter, CSPI says that McDonald's toy-related promotions violate state consumer protection laws in four states and the District of Columbia. The letter gives McDonald's 30 days to agree to stop the practice before a suit is filed.
The nutrition group claims that using toys to entice children instills bad eating habits and puts kids at higher risk of risk of developing obesity, diabetes, or other diet-related diseases over the course of their lifetime.
McDonald's disagreed with the CSPI's criticism, saying that its U.S. advertising campaign is focused on low-calorie Happy Meals.
"We couldn't disagree more with the misrepresentation of our food and marketing practices," McDonald's spokesman William Whitman said in a prepared statement.
"McDonald's is committed to a responsible approach to our menu, and our Happy Meal offerings," he said. "We have added more choice and variety than ever before, a fact that has been widely reported and recognized."
CSPI director Michael Jacobson acknowledged that parents bear much of the responsibility for children's eating habit -- a criticism industry defenders often levy.
"But multi-billion-dollar corporations make parents' job nearly impossible by giving away toys and bombarding kids with slick advertising," he said.
Herbalife shares tumble after the maker of nutritional supplements reports earnings that fall short of analysts' estimates. More
New annual report from U.S. government shows the long-term prognosis for Medicare has improved thanks to slower health spending, while the outlook for Social Security remains unchanged. More
Online dating site OkCupid found its users were more likely to have conversations when it told them they were more compatible than in reality. More
Actor-founded This Bar Saves Lives had Hollywood connections, but learned Start-Up 101 the hard way. More
Steve Mason, a pastor from California, inherited more than $100,000 in student loan debt when his 27-year-old daughter died suddenly in 2009. With interest and late penalties, the debt has since ballooned to $200,000. More