The Center for Science in the Public Interest (CSPI), a consumer advocacy group focused on food issues, announced this week that they would be pursuing legal action to stop McDonald’s from including toys with their kid-centered Happy Meals. They claim the practice is “unfair and deceptive” and have given the chain 30 days to comply.

In 2006, fast-food companies spent more than $520 million on advertising and toys to promote children’s meals, according to a U.S. Federal Trade Commission report. Such advertising appears to have significant influence over children and has come under scrutiny in the United States, where obesity is an epidemic.