Consumer watchdogs want to take the "happy" out of McDonald's (NYSE: MCD) Happy Meals. But isn't a Happy Meal without a toy just a regular Mickey D's meal?

The Center for Science in the Public Interest has threatened to sue McDonald's in an effort to get rid of the toys that promote Happy Meals. It claims that toy-related promotions are "a deceptive and illegal marketing practice," and that such promotions violate consumer-protection laws in Massachusetts, Texas, Washington, D.C., New Jersey, and California.

McDonald's CEO Jim Skinner is returning fire, saying he'll defend McDonald's vigorously (they always say "vigorously"). In a letter, he wrote, "CSPI's twisted characterization of McDonald's as 'the stranger in the playground handing out candy to children' is an insult to every one of our franchisees and employees around the world."

CSPI's slam is an affront to consumers, too. Groups that pursue companies for such marketing practices insult the intelligence of parents, who, last I heard, had the final say in what their children got to eat.

Granted, there's a growing emphasis on improving diets and preventing obesity and diabetes in America. Investors had better prepare themselves for the likelihood that McDonald's, Burger King (NYSE: BKC), Yum! Brands (NYSE: YUM), Coca-Cola (NYSE: KO), PepsiCo (NYSE: PEP), and many other food companies will face challenges similar to the legal and regulatory woes tobacco companies such as Reynolds American (NYSE: RAI) and Altria (NYSE: MO) have confronted for decades.

Since 1965, the U.S. smoking rate has been cut in half, to just 20% of adults. Ultimately, the tobacco companies have had to submit to substantial FDA regulation. With smoking on the wane, watch our collective public-health emphasis shift to the food industry. At this point, it's a far bigger target.

Forward-thinkers such as Coca-Cola and PepsiCo have already taken initial steps to ingratiate themselves with officials. Pepsi has been emphasizing its "good for you" products, and even promoting them as growth drivers. Both Coke and Pepsi have also reduced sugar (specifically, high-fructose corn syrup) in some of their sports-drink lines.

Hopefully, parents use critical thinking in all their purchasing decisions, and pass that skill to their children, too. Marketing can be a powerful force driving what people want (or think they want), but ultimately, you can't force anybody to give a flying French fry about such things. People always have a choice in their purchases.

Those of us who grew up enjoying an occasional Happy Meal (and somehow managed to survive!) probably hope that McDonald's management can defend against these sometimes smug, joyless, often condescending crusades. Life is all about choices, in the consumer realm and many others. People who want to make others' choices for them don't make the world a better place. They might just make it a little less happy.