The battle between “tastes good” and “good for you” has been waging at kitchen tables for decades. Fortunately, kid-targeted cereals have often come to the rescue –at least for breakfast. Mom and Dad can approve flakes fortified with vitamins and minerals . . . and kids can dig around for marshmallows in their bowl when their parents aren’t looking.

But, those cereals lose their appeal when kids grow up, right? Surely, no one over the age of 18 wants to stare down a leprechaunover their first cup of coffee?

Image courtesy of PB Nation

You’d be surprised.

AdAge recently reported that adults now comprise 45 percent of the market waking up to hearts, moons and clovers every morning. And though kids undeniably remain the cereal’s target audience, General Mills has designed an ad campaign to speak directly to Lucky Charms’ older fans—those who never left and those who would like to return to the rainbow.

Critics say the shift in targeting might be a response to pressure General Mills has faced regarding childhood sugar consumption and obesity, but the company maintains there’s no hidden agenda. Rather, it appears General Mills is betting adults won’t mind public acknowledgement of their sometimes secret affections.

For marketers, this move offers more value than purple horseshoes and red balloons. Here are a few lessons I think we can learn from the leprechaun:

Stay agile to stay relevant. In today’s volatile marketing environment, agility is more important than ever. Marketers need to adapt their messages and targeting when consumers shift or when new opportunities emerge —otherwise, there’s little chance to stay relevant.

General Mills knows even a 50 year-old brand stalwart has the potential to change and still thrive if it can reach out to the right audience in the right way. In this case, the brand’s history is the key to its advertising shift: “Remember this cereal you once loved?”

Don’t scrap what’s working. General Mills hasn’t reduced the amount of Lucky Charms spots aimed at kids; instead, the company added “grown-up” spots to the mix to address the increasingly diverse age demographic the brand serves. All of your messages don’t need to change just because you want to extend what you do.

Have some fun. This Lucky Charms spot is meant for adults, but it’s not an info-mercial about the cereal’s nutritional impact. A sense of humor and an obvious love of fun can make a big difference in keeping your customers happy –plus, it increases the likelihood your message will be shared across social networks. Are there ways you could inject a little “magic” into your marketing strategy?

Never underestimate the value of nostalgia. In good times and in bad, we all tend to look back with rose-colored glasses, and often the brands and products we loved in our younger years seem even more appealing when remembered.

Ultimately, if you were a Lucky Charms (or Cinnamon Toast Crunch or Apple Jacks or Count Chocula or Froot Loops . . .) kid, a hankering for more innocent times could easily turn you into a Lucky Charms grown-up now. Maybe you would even wants to share that memory and experience with your own kids –which, of course, is the real pot of gold General Mills is hoping for with this campaign.