Does Work Make You Fat?

Some scientific evidence supports employers’ efforts to manipulate the workplace environment in ways designed to help workers avoid unhealthful behaviors.

By Susan J. Wells Oct 1, 2010

October Cover


It began in 2003 with a simple idea to help improve employees’ health and fitness: challenge them to eat five cups of fruits and vegetables and walk 10,000 steps a day. The competition, launched by Wegmans Food Markets Inc., pit department against department and store against store, with results published weekly and prizes bestowed on winners.

Two years later, the program was so popular that Wegmans recruited six other Rochester, N.Y., employers, along with the Rochester Business Alliance, to join the campaign.

In the past four years alone, 125,000 employees from more than 300 organizations have participated—walking 49 billion steps and consuming 20 million cups of fruits and vegetables.

"The magic of it was making it competitive and fun, but the collaboration and camaraderie are the key," says Paul Speranza, Wegmans’ vice chairman. "Say I work for Xerox and my neighbor works for Eastman Kodak, and we’re both doing the same program," he says. "We can talk about it over the backyard fence."

The bottom line: "Surround people with good vs. bad health behaviors—and it’s more likely to motivate them toward sustainable health changes," according to Speranza.

Like Wegmans and the alliance, many employers and their wellness leaders are now harnessing the power of social connections as a strategy in the workplace battle to reduce obesity. These policies come just as the National Center for Health Statistics estimates that medical expenses for obese employees are 42 percent higher than those for employees with healthy weights.

"Leveraging social networks is currently very popular to accelerate engagement," says LuAnn Heinen, vice president of the National Business Group on Health in Washington, D.C. "It is the theory underlying the challenges and competitions we’re seeing, as well as the use of health champions," or peer leaders among the ranks who can foster change.

In addition to encouraging employee participation and creating positive buzz around healthful behaviors, such programs have scientific evidence to back them up, as research more strongly links social, occupational and environmental factors to the tendency of working people to gain weight over time.

Social Link: Can Co-Workers Make One Another Fat?

Such is the crux of one popular theory put forth by Dr. Nicholas Christakis, a professor at Harvard University, and James Fowler, a professor in the School of Medicine at the University of California in San Diego.

They contend that there’s a social contagion factor to the spread of obesity—a finding summarized in a 2007 article in The New England Journal of Medicine.

In their research, they evaluate the weights and body mass indices of more than 12,000 people who are part of the Framingham Heart Study—a decades-long analysis of heart disease in a Massachusetts town. The study was launched by the National Heart Institute in 1948 and has tracked generations of participants.

Using statistical models, Christakis and Fowler sifted through the years’ worth of data, eventually creating a map of how 5,124 people were connected—a web of 53,228 ties between friends, family and work colleagues.

Next, they analyzed the data, beginning by tracking how and when residents became obese. From this came a diagram of the entire social network—with each resident represented as a dot that grew bigger or smaller as the person gained or lost weight for 32 years, from 1971 to 2003. What they found was that obesity occurred in clusters—with weight gain actually spreading to nearly 40 percent of the social network of friends, siblings, spouses and neighbors.

Specifically, obesity seemed to spread like a virus through social ties; if one person became obese, the likelihood that his mutual friend would follow suit increased 171 percent, the study shows. And the effect didn’t stop there; it appeared to skip links, Christakis says.

A person was about 20 percent more likely to become obese if a friend of a friend became obese—even if the "connecting" friend didn’t put on weight. A person’s risk of obesity went up about 10 percent even if a friend of a friend of a friend gained weight, the analysis shows.

"We’ve always lived in these interconnected webs of relationships where we influence people—not only those we’re directly connected to, like family, but also our friends, their friends and their friends’ friends," Fowler says.

Evidence for other transmissible traits and behaviors emerge from the same data set; many are described in Connected: The Surprising Power of Our Social Networks and How They Shape Our Lives (Little, Brown and Co., 2009). In the book, Christakis and Fowler write that "everything we think, feel, do or say can spread far beyond the people we know," and that "you may not know him personally, but your friend’s husband’s co-worker can make you fat."

For employers, Christakis says, there is value in realizing the reach—and impact—of work/life ties.

"The question is, ‘Are there interventions that we can exploit to take advantage of the social network phenomenon to improve health?’ " Christakis asks. "The answer is yes, and one of the dynamics is that group interventions are more effective than individual" ones.

For example, weightloss interventions that provide peer support—that modify the behavior of people within their social networks—are more successful than those that don’t.

"People are connected," he says. "Their health is connected."

Christakis and Fowler’s claims have prompted challenges among scientists, including Jason Fletcher, assistant professor at Yale University’s School of Public Health, and economist Ethan Cohen-Cole, with the Federal Reserve Bank of Boston. In two 2008 studies, they examine data from a federal government project that tracked the health of 90,118 students at 144 high schools and middle schools from 1994 to 2002.

When Fletcher analyzed the student cliques by using statistical tools similar to those used by Christakis and Fowler, he found that social contagion indeed existed. But the conditions that were apparently catching were entirely unlikely—conditions such as acne, headaches and height. When the researchers applied stricter methods to control for environmental influences, the contagion effects disappeared.

The two studies concluded that "the spread of obesity is related to the environment in which individuals live. Though we do not completely rule out the possibility of induction and person-to-person spread of obesity, our results suggest that shared environmental factors can cause the appearance of social network effects."

Fletcher says at least three theories explain the link between friends and obesity status:

  1. Shared environment. Having a lot of fast-food restaurants in a neighborhood, for instance, increases the chances of obesity for everyone.
  2. The "birds of a feather flock together" phenomenon, or people’s tendency to choose like-minded individuals to be their friends.
  3. The effects of friends’ behaviors on an individual’s obesity.

While the work of Christakis and Fowler sought to isolate theory No. 3, "our paper indicates No. 1 might be quite important," Fletcher says.

Social network analyses undoubtedly will play a role in deciphering how relationships affect health, but, as the field develops, evidence points to occupational and environmental factors that undeniably shape health.

Case in point: sedentary jobs.

The Occupational Link: Can Your Job Make You Fat?

It’s well-documented that the rates of obesity, heart disease and many other chronic diseases are lower in people whose jobs require physical activity. Yet it’s also true that work in many types of jobs today doesn’t provide physical activity.

This trend toward sedentary jobs marches on, as measured by the Behavioral Risk Factor Surveillance System, a monthly telephone survey established in 1984 by the federal Centers for Disease Control, as the agency was then named. The system allows state officials to monitor adults’ health and occupational behaviors, including those that lead to obesity.

According to federal data, the proportion of sedentary jobs in the economy more than doubled from 1950 to 2000, when 27 of every 100 workers held sedentary jobs.

When researchers began to look into the positives associated with work-related physical activity, they realized that there are few studies documenting the physical activity of many common occupations, says John P. Porcari, a professor of clinical exercise physiology at the University of Wisconsin in La Crosse. That led to a 2007 study published in Medicine & Science in Sports & Exercise.

Author Porcari and his colleagues gave pedometers to 98 workers in 10 occupations and asked them to wear the devices for three workdays.

Secretaries logged an average of 4,327 steps—less than half the often-recommended goal of 10,000 steps a day for optimal health.

"Our results opened a lot of eyes—there was almost a fourfold difference between the most active and the least active" professions, Porcari says.

The message for employers? Worksites offer opportunities to encourage employees to increase physical activity—especially as most adults spend half of their waking hours at work, he says.

And encouraging workers to move more reaps benefits, he says. "People who are more active generally are more productive."

Supporting even small bursts of opportunity to move more during the workday—lunchtime walks, bicycling, fitness centers or step competitions—can help, he says.

How Many Steps a Day?

On average, not that many...





Police officers




Construction workers


Factory workers


Restaurant servers




Mail carriers


Interestingly, so can allowing employees to wear casual clothes, concluded another study by Porcari and University of Wisconsin researchers. In that experiment, 53 employees from various companies wore pedometers for two workdays—one spent in regular office attire and one in jeans.

Findings show that employees took an average of 491 more steps each on the days when they wore jeans. The 2004 study was published in Cardiopulmonary Rehabilitation and Prevention.

During the course of a year, the researchers suggested, the magnitude of this increase could offset the weight gain of 0.4 to 1.8 pounds experienced by the average adult in the United States each year.

The Environmental Link: Can the Workplace Make You Fat?

Scientists offer fresh evidence that obesity and overweight may be related in part to adverse work conditions. In particular, the risk of obesity may increase in high-demand, high-stress and low-control work environments, and for people who work long hours.

"Traditionally, practitioners have looked at wellness and health promotion in isolation from occupational health concerns arising out of the work itself," says John Howard, director of the National Institute for Occupational Safety and Health. "Increasingly, however, in the face of spiraling medical costs, health professionals and scientists recognize that it makes sense to address health issues holistically."

In fact, while eating patterns were once seen as being driven primarily by individual choice, Howard notes that recent research identifies environmental workplace factors that actually foster overeating.

For example, chronic job stress and lack of physical activity are strongly associated with being overweight or obese, according to University of Rochester Medical Center researchers who studied 2,782 employees at a large manufacturing facility in New York.

Unexpectedly, researchers found that a diet rich in fruits and vegetables seems to do little to offset the effect of chronic job stress on weight gain among the employees, who were mostly sedentary. Instead, exercise seemed to be the key to managing stress and maintaining a healthful weight. The Journal of Occupational and Environmental Medicine published the research in January.

Lead author Isabel Diana Fernandez, an associate professor in community and preventive medicine at the University of Rochester Medical Center, says her study is among many that associate high job pressure with weight gain and other related conditions.

"People react differently to stress; some overeat, some eat less," she says. "Stressful working conditions are known to impact health behaviors directly and indirectly. But addressing, mitigating or at least dealing with the psychosocial conditions and level of acute stressors experienced in the workplace appears to impact how employees will react."

During the study, Fernandez’s team heard the same story repeatedly from employees: After spending the day sitting in stressful meetings or at their computers, they looked forward to going home and "vegging out" in front of the TV. Anecdotally, researchers discovered that when pink slips were circulating, the snacks highest in fats and calories would disappear quickest from the vending machines. Some workers said they didn’t take time to eat well or exercise at lunch because they were afraid of repercussions from leaving their desks for too long.

The study dates back to 2005, when, amid growing concern of an obesity epidemic, Fernandez was awarded a $3 million grant from the National Institutes of Health to investigate ways to influence employees’ dietary and physical activities at work. At the time, the company she studied was restructuring and laying people off. In interviews, employees confided to researchers that they were "stress-eating" and burned out from "doing the work of five people."

The research team measured these psychosocial work conditions through a detailed job questionnaire. Interventions were planned, and employees who worked at intervention worksites participated in a comprehensive, two-year nutrition and exercise program. This included workshops on walking routes at work, portion control in food and stress-reduction. The data comparing control groups and the groups that took part in the nutrition and exercise program are still being assessed, Fernandez says.

However, researchers have already discovered that employees working in the most stressful jobs had almost one body-mass-index unit more weight than people who worked in more-passive areas.

In conclusion, the research suggests that workplace wellness planners should offer business leaders and all employees a range of ideas on how to be healthy and minimize stressful environments.

"Focus on strengthening wellness programs to provide good nutrition, ways to deal with job demands and more opportunities for physical activity that are built into the regular workday without penalty," Fernandez advises.

"We made a case for taking care of the wellness environment in the workplace."

The author, a contributing editor of HR Magazine, is a business journalist based in the Washington, D.C., area.

What do you think about researchers' efforts to link employees' weight gain with workplace behavior?

Have you taken steps to manipulate the workplace environment in an effort to help employees avoid either the temptation to overeat or to eat less nutritious foods?

Share your ideas and initiatives with your peers in the discussion area below.

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