The new millennium is barely five years old and we are losing further precious ground in the fight against obesity. In the year 2000, the Department of Health and Human Services issued Healthy People 2010, which set health goals for the nation to achieve within the first decade of the 21st century. At the time, the most recent data (from the early 1990s) indicated obesity prevalence in U.S. adults stood at approximately 23%, and the goal for 2010 was to reduce obesity to a population prevalence of 15%. Based on the most recent prevalence data released in 2000, obesity (body mass index ≥ 30) rates top 30% (Fig. 1), and another 30% or more of adult Americans are overweight (body mass index ≥ 25–30) (5). Obesity prevalence has gone up in every demographic group in every corner of our country. In the wake of this rising tide of overweight Americans are the inevitable consequences of increased rates of diabetes, hypertension, dyslipidemia, hyperinsulinemia, and this constellation of risk factors occurring together under the name metabolic syndrome. We are going backward in our battle against this epidemic.
Even more distressing is the dramatic rise in overweight children and obesity among children. Obesity prevalence has doubled in young children and has tripled in adolescents since 1980, and in the 1990s, new diagnoses of type 2 diabetes rose 10-fold at major children’s hospitals. The Centers for Disease Control and Prevention has said that if this trend continues, one in three children born in the year 2000 will become diabetic in their lifetime.
Why are we not making progress now that we have taken direct aim at this problem? Unfortunately, the Healthy People 2010 report did not come with an owner’s manual telling us HOW to achieve the goals it described. We have made great strides in identifying how much physical activity people should have to manage body weight, and we know a lot about the quality and quantity of food that can promote good health. However, we do not have a clear strategy for how to bring this about and to sustain it population-wide. What we do know is that simply providing people with the information about behavioral goals is not sufficient for them to adopt and sustain new behaviors.
Of course, we are not failing for lack of trying. The public clearly has heard the message that they need to lose weight. Witness the phenomenal popularity of low carbohydrate diets over the past several years. Literally millions of people were eschewing everything from bread to beer in favor of high protein, often high fat, fare in hopes of losing pounds without having to eat less food. Many people lost weight, even lots of weight, but few have kept it off (11). It was not for lack of availability of low carbohydrate products because there were thousands of new low carbohydrate product introductions, and sales of these products were robust while demand lasted. Perhaps it is just too hard to eat such a restrictive regimen over the long haul. Perhaps it is not possible to achieve and maintain healthy weight through dietary change alone. What about the need for physical activity? Perhaps our cultural tendency to want the “magic bullet” will forever doom us to failure if the real solution requires changing more than one thing at a time.
What has gone wrong? What is causing this epidemic? Who is the culprit?
There is no shortage of opinion about what is causing the problem and what the possible remedies are. However, because of the complex nature of the problem, little direct scientific evidence exists that can be used to disentangle the multiple causes to assign portions of the blame.
The American lifestyle is “obesogenic” in nearly every respect. Good-tasting, high-calorie food is available nearly everywhere, and it has never been less expensive in relation to our income. This same food is advertised aggressively, creating an environment in which people are literally surrounded by cues and temptations to eat. When you decide to eat, you are further tempted to eat more than you might otherwise by promotions that appeal to your American sense of “the deal”: “Buy one, get one free.” You can increase the size of your order for only a few more pennies or receive a free dessert if you buy the large meal—and on and on. Although hard evidence may be lacking for many of these potential villains, it is likely that each of these factors and many others (Fig. 2) contribute something to the overeating phenomenon prevalent today.
Of course, our biology is designed to encourage us to eat or at least consider it whenever food is available. For millions of years, we never had a consistent and abundant supply of food, and we always had to be tremendously physically active to subsist (9). We developed preferences for foods high in sugar and fat because these were dense sources of much-needed energy. For the past several thousand years, humans have toiled to perfect agricultural and farming methods to provide an abundance of these energy sources as inexpensively as possible. And, we have succeeded. At present, sugar and fat are the cheapest sources of calories on earth (3). These abundant commodities keep food prices low and make it possible for nearly every American to have enough calories and, apparently for most individuals, too many in relation to their level of physical activity.
At the same time that we enjoy abundant, great-tasting food, we have evolved to a lifestyle where physical activity is essentially no longer required for subsistence. We have made physical activity obsolete as a necessity for survival, and our advance toward complete sedentariness shows up in nearly every aspect of our lives (Fig. 2). There are more cars in America than ever before, and we make extensive use of them to cover ever shorter distances. Fewer and fewer people have jobs that require them to engage in significant physical activity. More and more people have sedentary jobs where, in effect, they are being paid to sit at a desk and not be physically active. All this is made possible through the progress of technology. We build our new communities with big homes and big plots of land (low population density) lining streets that are poorly interconnected (e.g., lots of cul-de-sacs) and where it is difficult to go anywhere without crossing a major thoroughfare with several lanes of traffic. It is no wonder that our children no longer can walk or ride their bikes to school without safety concerns, and it is not surprising that no one would think of walking to the corner store for a loaf of bread. In many neighborhoods, there no longer is a corner store, and even if there is, it probably can’t be reached safely on foot!
We seem to be in love with technology, especially if it enhances productivity or personal entertainment. It pervades every aspect of our work, home, and social lives. In our eternal quest as a capitalist society to market and sell more goods and services, we have transformed our daily existence into one that requires essentially no physical activity to subsist. It has been said many times that we have literally engineered physical activity out of our lives. Even walking, which is the most prevalent form of daily activity for most people, has dropped to extremely low levels in large segments of the population. Recent data from a national survey of physical activity levels (assessed by pedometers worn for several days) show that the average American walks only approximately 5300 steps per day (10). This is roughly half of the commonly recommended dose of at least 10,000 steps per day, which probably equates to 45 to 60 min of moderate physical activity in addition to lifestyle activity. Populations that still live a lifestyle like our forebears a century ago, such as the Amish, average more that 18,000 steps per day among men and 14,000 among women (1). It is likely no coincidence that the prevalence of obesity in the Amish population studied was 0% for men and only 9% for women.
The correlation between an active lifestyle related to occupational mode and reduced body weight and disease risk is not new. In 1953, Morris et al. (8) published an elegant study described as the “epidemiology of uniforms.” Morris et al. compared the waist and chest sizes of tailored uniforms worn by either bus drivers or bus conductors in London. Drivers spent most of the day sitting and driving, whereas the conductors on the double-decker buses spent their time climbing up and down the stairs collecting fares from patrons. Although it was not possible to correct for all possible confounding variables that might have been different between drivers and conductors, these investigators observed a greater waist and chest circumference among drivers compared with conductors at all ages. Likewise, they examined disease risk and death in these two populations and found the same relationship—the drivers had much greater rates of heart disease, diabetes, and death compared with the conductors.
The steady advance of sedentariness does not stop at the workplace. The array of sedentary entertainment that competes for our leisure time continues to grow, and each new generation of technology seems to be more engaging and irresistible than the last. We spend literally hours sitting watching television, playing video games, or engaging in other “screen” activities (15). Technology continues to advance at a pace that provides a steady stream of new capabilities that we seem to want without question or further thought. If it increases productivity, saves time or physical energy, is fun and “cool” and provides immediate gratification, we want it!
THE THRESHOLD EFFECT
Mayer et al. (7) in the 1950s observed that in both rats and humans, regulation of body weight was more precise when physical activity was above some threshold that they termed the normal activity range. Below this level of activity was what they labeled the sedentary zone, in which activity was low yet food intake was not reduced to match the low energy expenditure but, conversely, was increased. Of course, this resulted in greater body weight for the sedentary subjects compared with the more active groups. Above the sedentary classification, food intake was well matched to energy expenditure and body weight remained constant for people of similar stature, despite widely ranging total energy expenditures that occurred as a function of different occupations. Mayer et al. concluded that susceptibility to obesity at low activity levels is understandable given that only recently it was possible for humans to achieve such a sedentary lifestyle and still survive. We were not designed as a species to adjust food intake downward when activity is below the level that was typical for people until the latter half of the past century. Even if the biology urged reduced food intake, it would be hard to achieve in the current food environment.
DRIVERS BENEATH THE SURFACE
Clearly, our lifestyle has changed dramatically in the last century, and these changes have made high-calorie food widely available and have made physical activity scarce. It is easy to look around and see how our environment promotes overweight Americans and obesity. However, the critical question is not how the environment does this, but rather, WHY is the environment the way it is? Making significant progress toward changing the current obesogenic environment would seem to depend on an understanding of the major economic and social systems shaping our environment, and how these might be changed.
Economists would probably tell us that things are the way they are because that is what people want (2). Collectively as a society, we construct systems and markets to service the will of the people, and the “environment” will continue to evolve to deliver these desires as cheaply, conveniently, and efficiently as possible. Clearly no one set out to make Americans obese. What we see today are the unintended consequences of many individual, social, political, and economic decisions made for other reasons—probably without consideration of the potential effects on obesity. Our challenge, then, is to understand better how these decisions are having detrimental consequences and how we can alter them in the future to support a different outcome.
American values are undoubtedly at the heart of many of these decisions. Among the many values that define us as a nation, we value personal liberty and the pursuit of happiness. For many, personal liberty means having freedom to choose. And in our market economy-driven society, pursuit of happiness often translates to the acquisition and consumption of more goods and services that deliver tangible and desirable benefits. Having the “good life” in America means having, among other things, a steady job that does not require hard physical labor, having abundant and affordable food, and having the opportunity and freedom to pursue the American dream. Many of the systems that support this economy are self-reinforcing because they make it easier and easier to acquire the goods and services that unintentionally promote obesity. For example, the easy availability of credit so that people can “buy now and pay later” allows people to enjoy instant gratification. Whether an individual buys a new television or a new car or charges a big meal at a nice restaurant, it is easy to do, it makes us feel good immediately, and we likely do not think much about the long-term implications or consequences of those decisions, especially with regard to our health. Rising standards of living in large segments of the population mean that more and more people can enjoy these immediate benefits. The consequences of these decisions, whether they impact health or personal financial stability, are postponed far enough into the future so as to be discounted.
As a society, we seem always to be in search of bigger, better, and cheaper. We always seek to grow the gross domestic product, to advance technology, and to lower costs. Accompanying these broad societal goals have been other trends such as changing labor markets, economic globalization, and so forth that in turn have affected family structure (e.g., more women working outside the home) (14) and neighborhood structure (e.g., suburban sprawl) in ways that reinforce current social systems. Perhaps most disturbing is that our bank account of “social capital,” which reflects our collective engagement in civic matters and our own connectivity with one another (12), is being depleted. The net effect of this loss of social capital is a diminished capacity for social dialog and ultimately social change. We no longer seem to have meaningful discussions about what we want for ourselves and our children and what we can do as individuals to make positive change happen.
TURNING THE SHIP AROUND
So, how do we arrest the obesity epidemic and begin to reduce the prevalence in the population? First, I think we need to recognize more broadly that the epidemic we are experiencing is caused by the economic and sociocultural system we have built over the past century. This system served us well as a nation, improving standards of living for the average citizen beyond anything else in the world. Obesity is an unintended consequence of these systems, and to reverse the trend, we will have to modify the systems.
This is a daunting task and will take time. We did not create the current environment overnight, and we likely will not be able to create a new, healthier environment overnight, either. The good news is that we have succeeded in the past in changing social norms when we put all the right elements into place and we institutionalized systems that made the change a part of everyday life. There are numerous examples of things that are commonplace today that would not have existed just a few decades ago. Smoke-free environments, curbside recycling, and widespread seatbelt use are but a few things we take for granted today. Each of these environmental and social changes took concerted effort on behalf of numerous sectors of society, and these movements shared many common success elements (Fig. 3) (4). Creating a sense of crisis among broad segments of the public, building a science base to understand causes and consequences, and strong advocacy for change were early key features of these previous movements. Other key success elements included achieving significant engagement of people from all walks of life, from consumer advocates to change agents (“spark plugs”) within communities. These people were instrumental in developing plans for action and in forming larger coalitions that ultimately pushed for government action and policy change. Throughout these movements, mass media and other channels of communication directly to the public were essential in keeping the issue in the forefront. And, doing all the homework to figure out how to make the desired goal economically feasible was critical to achieving and sustaining meaningful change. For example, making curbside recycling affordable was in part the result of identifying novel uses (market demand) for recycled plastic, such as insulation for outdoor clothing.
So, do we have the critical mass of success elements to arrest the obesity epidemic? Increased media attention to the issue over the past few years has driven awareness to a high level, but whether this translates to a feeling of crisis among average citizens remains to be seen. We are beginning to see multiple advocates emerge, and evidence exists of coalition building and community engagement for policy change at the local level. Witness the increase in school districts adopting more restrictive policies regarding food vending on school grounds.
Despite this evidence of progress, we still lack a broad plan for the nation to deal with this problem at all levels. As a starting point for such a national plan, I think we need to set more modest immediate health behavior goals for the population, goals that can be achieved within a reasonable period of time. There is no better encouragement than achieving one goal before setting sights on the next level of performance. Many of the authoritative reports that have issued recommending dietary and physical activity practices for the nation set goals that may be too far out of reach for most people starting from where they are today. The recently released Dietary Guidelines for example, recommends that people increase servings of fruits and vegetables to nine servings per day. But, the average intake in the United States has not even reached the five-a-day goal that was set years ago. Physical activity recommendations also have been stretched such that people are being advised to engage in at least 60 min·d−1 of moderate to vigorous activity to manage body weight and at least 90 min to prevent weight regain after weight loss. There are still large segments of the population that do not receive the 30 min·d−1 that is recommended for general health and well being. It is no wonder people are staying on the couch and throwing up their hands. How can we encourage them to take the first step?
Analysis of both cross-sectional and longitudinal cohort data sets has found that the median weight gain in the adult U.S. population is approximately 1.8 lb·yr−1 (6). This represents a positive energy imbalance of only 15 calories per day over the course of a year. At the ninetieth percentile, the imbalance is only 50 calories per day. After accounting for the inefficiency of excess energy storage, this means that preventing weight gain in 90% of the population would take a daily increase in energy expenditure of only 100 calories or a decrease in intake of 100 calories or some combination—the hundred-calorie target has been termed the energy gap. Walking an extra mile or approximately 2000 steps would burn the 100 calories, whereas leaving a few bites of food on one’s plate would save 100 calories. Promotion of these small daily changes is the basis of a new national initiative called America on the Move (www.americaonthemove.org). Most people can achieve the small changes needed to close the energy gap, and after they achieve this level of behavior change, they usually are ready to do more, to set another incremental goal that can further improve their eating and physical activity behaviors.
IS THIS ENOUGH?
In theory, if we could arrest further weight gain in the population today within one to two generations, we would not have an obesity problem. Our children would not gain excess weight, and their children would not be overweight, and so on. To achieve this, however, would require everyone to adopt these small daily changes and to do so on a consistent basis. This is not likely unless there are compelling reasons for people to do so. The behaviors that promote obesity (eating too much, and moving too little) provide an immediate reward (i.e., it feels good), which may be termed a biological incentive. Overcoming this powerful biological incentive system will require powerful counter-incentives that provide even more compelling immediate benefits.
There are few rewards and incentives for individuals and society as a whole to behave differently than they do today. How many times has your boss come into your office or cubicle at work and told you she needs to meet with you and she wants to conduct the meeting while taking a walk? How many times have you been offered a two-for-one deal at a restaurant and the food involved was a healthy choice? How many times have you received a rebate or other reward for driving fewer miles in your car or for walking or riding your bicycle to the grocery store or other neighborhood establishment? Most incentives in our society reinforce the very behaviors that promote obesity. You receive the best deals on the least healthy food, and it is an even better deal if you buy a large portion. You are rewarded for spending more time at your desk at work, not less. Robert Reich (14), former Labor Secretary in the Clinton Administration, observed that “work is organized and rewarded in America in a manner that induces harder work.”
Most public health initiatives that promote behavior change rely heavily on a person’s own self-interest to motivate lasting change. Although this is an important factor, it is rarely sufficient to sustain change, especially against the backdrop of our environment, which is designed to reward you to do the “wrong” thing. We need many new and powerful incentives and possibly disincentives to help people achieve positive and lasting health behavior change.
Such incentives could link health behaviors with other consumer behaviors that are currently part of our cultural value system. For example, it may be possible to promote awareness of physical activity (which can be an important first step toward increasing activity) by using pedometers as retail store loyalty cards. If the bar code on your loyalty card was put on your pedometer, you would have another reason to wear your pedometer. In addition, retail stores could provide incentives for patrons that use their “loyalty pedometer” to purchase healthy products in their stores. Consumers would benefit in several ways. They receive whatever deal the store is offering on the healthy products and the intrinsic benefits of those products, and they receive the health benefit of increased activity that results from wearing the pedometer and walking around the store searching for the great deals! The store benefits by having more people spending more time in the store walking around trying to find all of the great buys, and likely buying many other things that they did not even come for in the first place.
What about incentives (or disincentives) in the workplace? Why not make participation in a wellness program at work a requirement for health benefit coverage? Employees could still choose not to participate, but they would then have to pay for all of their own health insurance. This would provide a large incentive for participation, and there is accumulating evidence suggesting that those employees who participate in work site wellness programs have lower health care costs.
These may seem like trivial examples, but the point is that we need to look for all possible ways to encourage people to engage in healthy behaviors, and the approach does not always have to be head on. Encouraging someone to eat better or to become more active as a byproduct of some other motivator still counts.
Making lasting change come about is not likely to happen without more people becoming involved in their own communities, in their work sites, in their children’s schools, in their families. Our nation has undergone significant social upheaval within the past 50 yrs (12). This has been characterized by a loss of social capital, the human networks that have traditionally functioned as a sort of glue that holds our society together and allows us to work together to make important things happen. As individuals, we seem to spend more and more time isolated from one another. Whether this comes from spending more time in front of the television or from moving to a gated community, we are living more solitary lives. Putnam (12) contrasts these marked changes in how we lead our lives today to social norms years ago in which bowling leagues and other community activities dominated our leisure time. He argues that today we are, in effect, “bowling alone.”
If we are to overcome the threat represented by the obesity epidemic, we will have to leverage every bit of social capital we can muster as a society. Just as further weight gain can be stopped by making a few small changes in our daily lifestyle behaviors, restoring the social capital we will need to make these changes normative behavior within our culture can be accomplished by each of us getting involved in small things that everyone can do (Table). It is time we start.
John Peters is a full-time employee of Procter & Gamble Company, makers of packaged consumer goods, including Pringles snacks and Folgers coffee. He also is the CEO of the America on the Move Foundation, a nonprofit organization involved in promoting healthy eating and active living.
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