CSPI has publicly criticized the parternship between Coca Cola and the National Heart Lung and Blood Institute, arguing that "that letting Coke bask in their agency’s good reputation does American hearts far more harm than good." Basically CSPI doesn't think Coke or other similar companies should be allowed to support (and thereby get good PR from their affiliation with) groups advocating on health issues like heart disease, since Coke products are, to use the CPSI terminology, "obesigenic."
In a perfect world, I would love to ban the sort of apparent hypocrisy that the Coke partnership represents. The sad truth, however, is that there simply is not enough funding from traditional sources for groups doing valuable work on issues like heart disease, child hunger, and so forth. If Coke and ConAgra weren't allowed to support these organizations, the net result would simply be a cut in funding for the organizations.
So as much as the Coke/NHLBI parternship or the McDonald's sponsored Olympics seem worthy of disdain, I don't know that banning such arrangements would be in the public interest. Better to focus on ending the more offensive arrangements, where there is some form of implied or express endorsement of unhealthy products by organizations ostensibly trying to make us healthier. I'm talking, of course, about arrangements like the American Heart Association's Heart Check program, which until very recently would give its seal of approval to clearly unhealthy "lesser evil" foods like reduced fat cheesecake.
More on CSPI's open letter, here.