John Banzhaf began his career as an anti-smoking activist back in the 1960s, when he filed a complaint with the Federal Trade Commission that eventually led to the removal of cigarette commercials from TV and radio. The George Washington University law professor says it was the clever legal strategy—arguing that the now-defunct Fairness Doctrine required stations airing cigarette ads to carry anti-smoking spots as well—that appealed to him rather than the specific cause. As he told me a few years ago, "If I had seen a way to use some legal rule or principle I had learned to do something as an individual about another significant social problem—saving the whales, auto safety, or whatever else—I probably would have done that also."

Far from saving the whales, Banzhaf's current cause is the war on obesity. In what I would call his latest press release if I weren't reasonably sure that he is issuing another one as I write this, he reminds us that he is "the public interest law professor whose students put together the initial fast food law suit against McDonald's and won a settlement of over $12 million." That case was not really about obesity, since it involved French fries that the restaurant chain advertised as cooked in vegetable oil without mentioning that they were precooked in beef fat—to the dismay of vegetarians, Hindus, and Jews observant enough to worry about such things but not observant enough to avoid McDonald's altogether. More relevant to his fat-fighting credentials, Banzhaf "is also advising on the law suit filed against McDonald's by obese children."

The point of the press release is not merely to trumpet the accomplishments of the man who dubbed himself "the [Ralph] Nader of the cigarette industry" and who now aspires to be the Upton Sinclair of fast food. Banzhaf also wants to express his ambivalence about a British lawsuit against Weight Watchers planned by U.K.-based psychotherapist Susie Orbach, author of Fat Is a Feminist Issue, who is fast emerging as the Rachel Carson of the diet industry.

On the one hand, says Banzhaf, Orbach may have a point if it's true that Weight Watchers tells customers they will lose weight in the short term without informing them that most will gain it back in the long term. "Their failure to disclose what lawyers call this 'material fact' could make them liable for consumer deception," he concedes, helpfully explaining that "a 'material fact' is any fact which might affect the decision of a reasonable consumer considering a purchase." (In case you still don't get it, Banzhaf, always the educator, offers an example involving a gasoline additive.)

On the other hand, Banzhaf worries that the publicity surrounding the suit will discourage people from trying to lose weight. In short, "this suit may have legal merit, but could be counterproductive"—something Banzhaf didn't seem to worry about when he encouraged his students to sue bars that give women "Ladies' Night" discounts.

This newfound caution could be viewed as a product of the conflict between two anti-capitalist campaigns: the war on obesity and the fat acceptance movement, both of which condemn big corporations for brainwashing and fleecing the masses. Each suggests litigation targets, but it may not be possible for one man, even John Banzhaf, to sue them all without his brain exploding from the cognitive dissonance.

Then again, Banzhaf, who craves publicity more than litigious fast food junkies crave bacon double cheeseburgers, may just be peeved that he didn't think of suing Weight Watchers first.