Campaigns Walk the Invisible Tightrope

Every January, Madison Avenue gets into the betterment business, unleashing a flood of advertising that seeks to take advantage of the impulses among consumers at the start of a new year to improve themselves. Scores of millions of dollars are spent on campaigns for weight-loss plans, diet pills, low-calorie foods, gyms and fitness centers, smoking-cessation drugs and exercise equipment. Almost always, the pitches are upbeat and positive, seeking to instill feelings of empowerment and encouragement in those who want to effect change in their behavior and appearance.