Obesity is Contagious

America is the fattest nation on earth. About 68 percent of American adults are now classified as overweight, including the 30 percent designated as obese. Along with an increase in the American waistline has come an increase in obesity-related diseases, especially diabetes. The plumping of America has become our second greatest public health problem after tobacco, claiming 300,000 lives a year. The carnage this epidemic is producing and the drain on health care dollars from the diseases that accompany it are shifting public sentiment from a passive resignation to a desire for active policy. The Surgeon General has initiated a "call to action to prevent and decrease overweight and obesity."

As society initiates its battle to end the obesity epidemic, much can be learned from the similar battle waged against cigarette smoking over the past several decades -- a battle that has enjoyed some success. The act of levying heavy taxes on tobacco products, for example, constituted a politically safe way for the government to raise money. Public opposition to these taxes was minimal, and even smokers themselves paid the inflated prices with little protest. The lobbyists from tobacco companies tried to influence policy but their success was limited by the contempt the public has developed for these industries. Raising taxes on cigarettes had both a predictable and desirable effect. Each time the cigarette tax was increased, the government raised more money and, at the same time, fewer people continued smoking.

Restricting smokers to designated areas and outlawing smoking in public places also became national policy. The effect of separating smokers was to make the unhealthy behavior more difficult. Social isolation of smokers had a similar result to raising cigarette taxes -- fewer cigarettes were smoked. The rationale for having designated smoking areas was based on the premise that second-hand smoke is medically dangerous to nearby people who might inhale the fumes, but just exactly how physically dangerous is second-hand smoke?

Although some early studies showed that spouses of smokers might see a very slight increase in the risk of lung cancer and heart disease, more recent studies failed to confirm that. A large study of 35,561 spouses of smokers who were followed for 38 years was published in the British Medical Journal in May 2003. This study showed no increase in cancer or heart disease in the nonsmoking spouse. Although spouses did have more episodes of self-limited bronchitis as a result of irritation from the smoke, they were spared the more serious complications. The authors of the BMJ article concluded that the major danger for spouses of smokers was early widowhood! If the risk of medical complications from second-hand smoke is so minimal, even in people who have the intense exposure that comes with living with a smoker, the risk for a coworker -- or for someone who is sitting near a smoker in a restaurant -- is almost nonexistent. The real reason cigarette smokers have been banished is because of the social prejudice that has developed in the U.S. against the habit.

How does this apply to our present obesity epidemic? Why should we care what our friends or associates eat? Isn't eating just a personal choice?

While it is true that Americans suffer financially from the rising health care costs produced by irresponsible eating and physical inactivity, there are more than just economic concerns in the obesity crisis. Living in an obese society produces very real physical dangers for all Americans, even those of a healthy weight. We are all weight-interdependent and each one of us is at an added personal health risk of gaining weight if our friends or associates become obese. A study published in the New England Journal of Medicine in July 2007 clearly outlines that interdependence. The article followed the weight changes over time among the inhabitants of Framingham, MA, and as the population at large gained weight, the authors determined each individual's likelihood of becoming obese. The study discovered the presence of "networks of obesity" -- that is to say, members of a population are all interconnected in regard to weight. When people with whom we are closely associated gain weight, such as neighbors, family, friends, or a spouse, we are also at an increased risk of gaining weight. For example, if your mutual friend becomes obese, you have a 171 percent increased risk of becoming obese. If your friend's sister becomes obese, you also have an increased likelihood of becoming obese. Even when your friend's sister's neighbor becomes obese, you still have an increased risk. The increased risk for becoming obese goes out to four degrees of separation.

Perhaps this parallel weight gain is due to a parallel change in eating habits, possibly due to the sharing of unhealthy foods, or a similar decrease in activity levels. Most likely the shared behavior that produces the shared weight gain involves a combination of all these factors. Whatever the cause, it is in our personal and economic interests to make sure that our friends, neighbors, and relatives remain at a healthy weight because obesity is a contagious disease, and presents a greater risk to our health than having them smoke around us!

It is long past the time that we as a society should recognize eating behavior and physical inactivity as not just a personal health problem, but a national one. We need to place similar social pressure on obesity as we have on smoking. The principle of encouraging healthy life habits accompanied by the taxation and social isolation of unhealthy behavior -- as has been done with tobacco -- needs to be applied to the obesity epidemic. However, the public is still reluctant to accept serious government intervention, so we should start with simple measures. Business offices and hospitals, for example, in an attempt to improve their workers' health, could declare their workspaces as "healthy snacks only" areas. Instead of coffee breaks, workers should be given "exercise breaks". Hopefully, using the measures we have learned from the ongoing battle against smoking, we can overcome the obesity epidemic and improve the health of all Americans.