06/01/2012 10:38 am ET Updated Aug 01, 2012

A Supersized Dud

New York City Mayor Michael Bloomberg made big news on Wednesday with his proposed ban on large serving sweetened drinks. The New York Daily News labels the mayor "a big soda scrooge" while the New York Post sees a future with "no more supersized Cokes."

But will the proposal achieve anything more than big buzz? As with other such efforts from the mayor's office, it has so many loopholes that the answer is likely no.

Yes, big servings of Coke will be on the endangered list -- unless, of course, you go to a fast food joint, and order a fountain drink where you will still be able to get free refills. Big soda scrooge? Clever one-liner, but he can't be accused of being a big milkshake scrooge -- since you'll be able to chocolate up under the proposal. The mayor is tough on soda, but sweetened fruit juices or alcoholic beverages? Not so much. They too would be exempt.

Welcome to the latest campaign in Mayor Bloomberg's war on fat -- and his latest misstep in an effort to regulate America to a healthier diet.

Consider earlier, similarly splashy initiatives. Remember the regulation requiring calorie counts on restaurant menus? Here, too, the war on fat proves selective. Walk into the McDonald's at Times Square, and you can get a full calorie count on a quarter pounder. What about the delis in the area that serve up a pound of corned beef, lightly decorated with bread? No, since the regulation applies only to chain restaurants. The problem, though, isn't just the implementation -- it's the basic concept. Most major studies of the new menus find them to be ineffective at reducing overconsumption. A recent Columbia University study suggests many aren't even able to read the menus properly.

It's a persistent theme through the multi-year war on fat -- good on PR, bad on policy. When public health managers complained about low fruit and vegetable consumption, City Hall created a new bureaucracy to operate produce carts. An analysis of the city's own data shows the program has had no significant impact on civic dietary habits, except among residents who are already in the habit of eating fresh produce. Other proposals -- like regulating food stamps and tax on soda -- never saw the light of day, failing to win the needed support in Albany and Washington.

In New York's war on fat, what matters is the perception of action. Tangible results? Not so much.

In the United States, health costs are spiraling up as a result of the obesity epidemic. But that fact alone is not enough to justify any regulation or effort, especially when it comes to food -- backlash can destroy progress just as surely as indifference.

The real problem with obesity remains one of motivation, not law. This isn't like smoking, where every puff you inhale is poison, in any quantity. When it comes to obesity, many people simply don't see their daily dietary choices as important health decisions.

In 2005, New York's then-Commissioner of Health and Mental Hygiene said that only 39 percent of obese New York adults surveyed correctly described themselves as "very overweight." After years of alarming headlines and ad campaigns on the obesity issue, similar polls have shown limited change.

Bloomberg's buffet of hit-and-miss laws will do nothing to change this. To give a sense of how hard it would be to change behavior through legal penalties, a recent British study found that so-called fat taxes would have to be as high as 20 percent before they change behavior.

How to deal with the obesity problem? Certainly, government policy could be smarter. We need to emphasize physical education in our schools; children are spending too much time playing sports on their PS3s, and not enough time playing sports in the real world. Agricultural subsidies and regulations give an unfair market advantage to unhealthy foods. Health insurance policies should emphasize wellness, and not just sick care; yet Washington regulations (even after ObamaCare) make it difficult.

But, ultimately, Americans need to go back to the basics: families must eat out less, and eat together more. Government policies can't achieve this, just a return to common sense.

And that's the reason that Bloomberg's war on fat has been a failure. Sure, it will keep a third-term mayor in the news. But better health outcomes for New Yorkers? Not so much. It's time for a change in strategy, Mr. Mayor.