No, of course not! However, a coalition of health advocates seems to be making that assertion when they sent her a letter this week asking that she relinquish her sponsorship of Pepsi because, they insist, its deviously effective marketing of soda to children is a cause of childhood obesity. Never mind that childhood obesity rates are declining around the nation among all socioeconomic levels, the cause of obesity is not and never has been advertising. Additionally, the solution to any health problem our nation faces is not in the marketing of high-calorie foods. The real problem is that adults -- specifically those with the responsibility of raising children -- have abandoned their responsibility to instruct children about how to make healthy choices. The only way to inoculate a youngster from the relentless and ubiquitous marketing for less-than-healthful foods is to show them how to make overall healthy diet decisions. On the other hand, quieting the marketing of a single high-calorie product will do absolutely nothing to address the problem of obesity in America. There are a million other options on store shelves; if a brainless zombie teen is at the mercy of commercials featuring pop stars, then they will simply be pushed toward a different ad and a different product with equally high sugar content. At least, for its part, Pepsi as a company has been slowly making its products healthier and expanding its line of healthier alternatives. Other companies, like Kellogg's, have used their profits and their celebrity sponsors to fuel campaigns that encourage youth sports. While it’s questionable how much these strategies will address obesity, they are certainly more effective than simply demonizing celebrities who endorse products. Katy Perry, whose lyrics often promote a positive message of strength and self-confidence, is arguable a better role model for teens than many of the other performers out there. Obviously, she is free to decide which products and companies she wants to endorse. Of course, if and when Perry decides to end her sponsorship, Pepsi will certainly find another celebrity to take her place. Maybe Miley Cyrus would be interested in the job.