Proponents of law suits attacking, or regulation of, the advertising and sale of food that make us fat. (Like this guy) are advocates of a new kind of puritanism. They are seeking to save us from sin - or, more accurately, from being encouraged to sin by advertisers and fast food restaurants that want us to eat what we oughtn't to eat. They are trying to save us from being manipulated into doing something that will harm us.
It's for our own good! But do they go far enough? The modern liberal notion believes that the only enforceable purity is purity of the body. He or she seeks to prevent gluttony. But that that was only one of the deadly sins. Remember lust?
So how about some public interest litigation against, say, Abercrombie & Fitch or countless other advertisers for encouraging precocious sexuality. Let's recover the cost of out-of-wedlock births and sexually transmitted diseases? Maybe a class of gay men infected with AIDS could sue San Fransisco's bath houses and gay bars?
If we really have to be protected from ourselves, we've got a lot more to fear than Big Macs.