I believe that Kellogg should be required to pay a fine because its advertising was unconscionable. The fact that the ad misrepresented the numbers in the study was only part of the problem. The study itself was deliberately designed to be misinterpreted because it compared children who were hungry (no breakfast) to children who were fed. A real study to determine the value of Mini-Wheats would compare children who had various types of breakfast. Your failure to press for a fine signals other companies to do the same. If you really want to deter wrongdoing, you should also insist that Kellogg issue a corrective ad stating that the study itself was poorly designed.
In the Matter of Kellogg Company, a corporation, FTC File No. 0823145, Proposed Consent Agreement #541742-00005
In the Matter of Kellogg Company, a corporation, FTC File No. 0823145, Proposed Consent Agreement