As CBS News Correspondent Wyatt Andrews reports, Banzhaf thinks restaurants like McDonald's should explicitly tell you a Big Mac meal, for example, gives you most of the fat you need for the day.
"I think when people walk into McDonald's they know the food is fattening," says Banzhaf. "I don't think they have any idea how fattening.
"I think the fat suits could be the next tobacco."
If that sounds outlandish, listen to his latest strategy: the addiction theory, which claims that fatty foods create a type of addiction.
"There is growing evidence that fattening foods can cause the same addictive effect as nicotine," says Banzhaf.
To the restaurant industry Banzhaf is out there, but this is what he is relying on.
Researchers like Dr. Michael Schwartz, who studies obesity, believe obese people slowly lose the brain signal that says, "stop eating." He points to a very fat rat, being used in an experiment, as an example.
"His brain is saying, 'I don't have enough fat,'" says Schwartz, about the rat.
But a craving, Schwartz says, is no addiction.
"You can say you are addicted to air, but I don't think that's a compelling argument," he says.
Still, the legal question surrounding obesity will always be, whose fault is it, really, if you are fat?
Is it the restaurant's fault if your favorite food is a hamburger and fries?
In class, Banzhaf's own students lecture him on personal responsibility.
"It's not McDonald's fault they continue going there every day," says one of his students.
But the kings of Bazhaf-bashing own the Seattle restaurant Five Spot.
They've drawn up a fictitious contract.
"I release the Five Spot from all responsibility," it reads.
Anyone ordering a dessert called the Bulge, has to promise not to sue.
"People want to sign it," says restaurant owner Jeremy Hardy. "It's a fun way for them to go on record as saying this is ridiculous. Enough."
"Remember Gandhi said, 'First they ignore you, then they ridicule you, then you win,'" says Banzhaf.
He says he just wants to win information. He wants fat and calories listed on menus beside the price of the food. It's that or he'll claim the industry's liability for obesity is $150 billion.
French fries bearing a warning