Health activists are in a tizzy over sugar and fast food, which they blame for the obesity "epidemic." Responding to these concerns, politicians have sought to tax or regulate the alleged culprits. Tort lawyers, smelling tobacco-settlement-scale greenbacks, have been gearing up to sue companies producing sugary beverages. Last week, in an attempt to pre-empt this barrage of legislation, tax, and litigation, the Coca Cola Company announced that it would from now on "market responsibly, including no advertising to children under 12 anywhere in the world." But none of these actions are likely to have much impact on our waistlines; indeed, some may be counterproductive, while others are likely to burn a hole in our wallets. And for most of us, life just wouldn't be as sweet. Fortunately, there are better ways to achieve a healthy weight.

In the 1950s, less than 10 percent of the U.S. population was obese on standard measures; being overweight was viewed as a risk factor for some diseases; and weight control was considered a matter of individual responsibility. Today, more than a third of Americans are classed as obese. Meanwhile, obesity is widely described as a disease in its own right, which is blamed on companies seeking to sell us pre-prepared food and drink. If those claims were true, then the lawyers would make like thieves. But are they true?

Let's start with the claim that food and drink companies have made us fat. In The End of Overeating, published in 2010, former FDA commissioner David Kessler argued that we live in an "obesogenic" society in which companies are constantly tempting us with products high in salt, sugar and fat. This meme has caught on: in Salt, Sugar Fat, released in February, New York Times journalist Michael Moss repeats Kessler's accusation that food manufacturers seek to ensure that their products approach our "bliss point," by loading them with—you guessed it—salt, sugar, and fat.

It does appear that the main cause of our expanded girths is that we have been consuming more calories. Most of the increase in obesity has occurred since the mid-1980s (rates rose to around 13 percent in the 1960s but stayed more or less constant until the early 1980s), which coincides with a sustained binge on the part of a significant portion of the American public. The amount of calories consumed per day by an average American man rose from about 2,080 calories per day in the late-1970s to 2,400 in the mid-1990s to 2,600 in the early 2000s. Equivalent figures for women are 1,500, 1,650, and 1,850, respectively. Meanwhile, we seem to be expending about the same amount of energy as we did in the 1970s: In a 2003 paper, Harvard economists David Cutler, Edward Glaeser, and Jesse Shapiro concluded that "The available evidence suggests that calories expended have not changed significantly since 1980."

OK—so we've been eating too much. But are those food and drink companies to blame? Well, most of the increase in calories does seem to have come from pre-prepared snacks. Cutler et al. explain that the increase in availability of pre-prepared food and drink made it easier for us to eat more by lowering the "time costs" of preparation. That makes sense. In 1913, we certainly could have eaten lots of chips and cake and drunk lots of juice but it would have taken considerably more time to prepare them than it takes to open a few packages, so most of us would not have had the time to snack in the way that we do today.

But there is a twist. Cutler et al. calculated that even taking into account the consequences of our increasing girth, we have benefitted on net from the wider availability of pre-prepared foods and drink because they have reduced the amount of time we have to spend in the process of preparation. In that light, all the efforts made by food and drink companies to identify our "bliss point" seem benign, not malign as in the Moss account.

Moreover, it turns out that obesity is not quite the health disaster the tort lawyers would like it to be. In a 2005 paper published in the Journal of the American Medical Association (JAMA), Katherine Flegal and her coauthors showed that people who are "overweight" but not obese are less likely to die of any cause than people of "normal" weight. Meanwhile, people who are "grade 1" obese are as likely to die as "normal" people. Only people who are underweight or have grade 2 or 3 obesity are more likely to die. In other words, obesity can lead to health problems but does not necessarily do so—and is only a serious concern for people who are very obese. These results were confirmed in a follow-up study by Flegal published in JAMA in January, which analyzed 97 studies giving a sample size of more than 2.88 million individuals.

Now, the proportion of people with grade 2 or 3 obesity did increase significantly in the 1980s and 1990s, rising from about 5 percent of the population in 1980 to about 15 percent in 2000. But over the same period, the proportion of those with grade 2 or 3 obesity who died from all causes fell. The most likely explanation for this is some combination of the following: First, improvements in medical interventions addressing a range of obesity-related problems, from diabetes to cardiovascular disease, mean that people suffering these obesity-related ailments fare better today than they would have done 30 years ago. Second, whereas previously obese people tended not to get much exercise, many more are now both physically fit and obese. Most likely, the group that really do suffer substantial increases in health problems are those who are "grade 3" obese; and this may in part be because above a certain weight there seems to be a vicious circle of declining exercise and increasing weight—even though those who are most obese are likely to benefit most from exercise.

And so to "solutions." In an influential study published in Science in 2003, James Hill of the University of Colorado and three coauthors estimated that a reduction in calorie consumption—or increase in energy use—of 100 calories per day would be enough to keep most of us trim. Many health advocates argue that taxes or even regulation are the simplest way to achieve that objective. But would those policies work?

Soda taxes have been extensively studied. Initially, it looked like they would work. Several studies found that a tax would reduce consumption of the beverage in question. However, these studies failed to factor in offsetting behavior by consumers. In particular, when faced with a tax many consumers either buy a cheaper (own-brand) variety, or switch to other drinks that are equally calorific, such as juice or milk. In a 2010 paper in Contemporary Economic Policy, Jason Fletcher of Yale, and colleagues David Frisvold of Emory University and Nathan Teft of of Bates College, found that increases in taxes on sugary beverages do reduce the number of calories adults consume but, because of these offsetting behaviors, the effect is very small. In a subsequent paper published in the Journal of Pubic Economics, Fletcher and co. looked at purchasing habits of schoolchildren and found that "the decrease in calories from soft drinks in response to an increase in the soft drink tax rate is completely offset by the increase in calories from whole milk."

If taxes don't work, what about regulation? The main regulation promoted by health advocates is calorific labeling at restaurants. This might work if people paid attention to such labels—but most don't. In a detailed study of the impact of NYC's food labeling law published in the American Journal of Public Health in 2010, Tamara Dumanovsky and co. found that only about 20 percent of consumers used the calorie information. This probably explains why such labeling has little impact on calorie consumption at restaurants. Moreover, since most of the extra energy people consume (now about one third of all calories) is in the form of snacks rather than meals at restaurants, such a regulation is unlikely to have a significant effect on most people's waistlines. The same goes for regulations limiting the size of soda beverages sold in restaurants.

At this point, you may be throwing up your hands in despair. And maybe you should. But not at me. You should throw up your hands in despair at the false bill of goods you have been sold by the public health researchers who, as Helen Lee observes in a fascinating study recently published by the Breakthrough Institute, "set about defining the causes of obesity in ways that they believed would predispose the public to support societal action to bring the industry to account." Lee observes that this involved, first, redefining obesity as an "epidemic" (it isn't—because it is not a disease) and, second, defining obesity as an "involuntary risk" (it isn't—otherwise we'd all be obese, given that the alleged risk factors are so ubiquitous).

Unfortunately, this distortion of the nature of "obesity" has led us down a blind alley from which we must now retreat. The government is incompetent to decide what and how much each of us should eat and drink. Its attempts to influence our decisions have mostly been futile and sometimes counterproductive: for example, at least one study found that college-age men increased their energy intake when purchasing food at restaurants where the energy content was displayed. At the same time, government regulations and taxes distort our consumption decisions in ways that may reduce our level of satisfaction: for example, soda taxes encourage us to consume lower quality unbranded sodas—or reduce the amount of money we have to spend on other items.

What we eat and drink is, first and foremost, a matter of individual responsibility. Fortunately, some researchers have been investigating the real reasons some of us consume too many calories—and this research is yielding practical advice. Brian Wansink and his colleagues at Cornell University's Food and Brand Laboratory have been investigating practical measures that can be taken by individuals and organizations to encourage us to eat fewer calories. Many of Wansink's findings, detailed in his book, Mindless Eating, focus on addressing various cognitive biases that lead us to consume more calories than we intend. So, for example, when we eat off a large plate, we tend to underestimate the amount of food we're eating. Solution: eat off smaller plates. Likewise, when we drink out of shallow glasses. Solution: drink from tall glasses. When we eat chips straight from a giant container, we consume more than if we portion out chips into small bowls. And so on.

Meanwhile, contrary to the dire assessments of people like David Kessler and Michael Moss, companies are beginning to realize that they can provide nutritious food and beverages in ways that enable people to maintain a healthy weight. A group of CEOs of food and beverage companies has created the Healthy Weight Commitment Foundation, which seeks to encourage the public to manage their weight better by "balancing calories in with calories out." Because of the significant presence of member companies in the supply of food and beverages, the Foundation has great potential to communicate important messages about how most effectively to maintain this healthy balance. Beyond that the Foundation is reaching out directly to teachers, who have the potential to influence how kids think about diet and exercise. According to its website, the Foundation has so far reached over half of all U.S. elementary schools; that's pretty impressive.

Unfortunately, Coca Cola's decision to "market responsibly" might not help and could even be counterproductive. While the small-print qualifies the company's apparent blanket prohibition on marketing to children, saying that it will "not buy advertising directly targeted at audiences that are more than 35% children under 12," that still means it will have difficulty marketing healthy products and healthful messages to kids.

But there are also things the government can do. Or, rather, there are things the government can stop doing, such as distorting our consumption decisions. Among other things, the federal government could end its subsidies to food production, distribution, and consumption. That includes food stamps, which may only be used to purchase foods and beverages and has been linked to increased obesity; if instead people simply received a cash transfer, they could then make decisions themselves about how to spend their money. And governments at all levels could stop imposing arbitrary, discriminatory taxes on food and beverages. To the extent that these taxes incentivize consumers to avoid brand products, they may actually reduce access to the kinds of information that the brand companies seek to provide about maintaining a healthy weight.