Big Mac is a burger at McDonald's (NYSE:MCD). However, if you go by the latest supersized campaign against the company, it might also be the name of its typical customer.

Even as the company makes inroads with healthier salads and leaner cuts of chicken, it can't seem to shake its past. It's not alone. Yesterday's UK Times reported that Britain is getting ready to tack an "anti-obesity" levy on companies like McDonald's, Coca-Cola (NYSE:KO), and Cadbury Schweppes (NYSE:CSG). The proceeds would be used to build sports centers to encourage more active lifestyles.

Taxing harmful industries isn't new. Just ask Altria Group (NYSE:MO) how much it actually receives on the sale of a carton of cigarettes. Those prices at the pump are high, but a thick cut gets earmarked for taxes. We should be used to sin taxes by now -- and gluttony is a sin in certain circles.

But where do you draw the line? Sure, we're getting plumper all over the world, but who can escape the blame? Britain's Department for Culture, Media and Sports is reporting that just 38% of the country's children are participating in at least two hours of athletic activity weekly.

But what does a can of soda or a burger have to do with all this? At least until McDonald's begins delivering, it can't really be faulted for a growing number of couch potatoes. Television networks, video game makers, and Internet content providers would seem just as guilty -- if not more so -- than fast-food chains for promoting sedentary lifestyles.

After all, those are the industries that would suffer if the world's youth would take to the great outdoors. A sports center or a freshly paved tennis court doesn't even displace the industries being targeted. Those might actually thrive as parents are forced to pick up their kids with time short and fast-food drive-through convenience high.

No, it doesn't make sense. What next? A tax on the sale of William Hung CDs to erect opera houses? A tax on baseball day games to fund research on melanoma? Some days, those golden arches appear like a sanctuary from the insanity.

Is a fat tax fair? Will this hurt companies like Mickey D's or will it be a platform for positive press? Should the company be at fault even if it offers healthier alternatives? All this and more -- in the McDonald's discussion board. Only on

Longtime Fool contributor Rick Munarriz finds some taxes taxing. He does not own shares in any of the companies mentioned in this story.