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Super-Sized World: The Global Obesity Epidemic

Super-Sized World
Reported by
Keith Mulvihill

Posted January 31, 2011


Overweight and obesity, risk factors for type 2 diabetes, cardiovascular disease, hypertension, stroke, and certain forms of cancer, are responsible for a significant portion of the global burden of chronic disease. They are also implicated in the chronic disability that affects many people’s lives. These problems represent a significant challenge to public health experts and policymakers not just in the U.S. and other comparatively wealthy countries, but also in developing nations where their impact is compounded by the effects of poor infrastructure, persistent nutrient and even calorie deficits, and rapidly changing economic and demographic features accompanied by dramatic dietary adjustments.

At Super-Sized World: The Global Obesity Epidemic on December 9, 2010, the New York Academy of Sciences, the Sackler Institute for Nutrition Science, and the Johns Hopkins Bloomberg School of Public Health convened a panel of experts in public health to discuss everything from current scientific understandings of overweight and obesity to the clinical, economic, and health policy initiatives that might help to stem the tide of this dangerous epidemic. In their conversation, the speakers assessed body mass index (BMI) versus alternative measures of body fat, presented the latest research into the importance of fetal nutrition for adult health, evaluated the influence of environmental and genetic causes of overweight, and explained the differential burden of disease for ethnic, gender, and socioeconomic groups. Driving at the heart of these and many other issues, speakers also emphasized the need for a re-conceptualization both of the categories of overweight and obesity and of the way public health policy efforts that are marshaled combat the epidemic.

Speakers proposed, among other options, multi-faceted interventions that recognize the intersections of various causes of disease, a new policy-oriented framework for scientific research, and policy measures to change the kinds of food and physical activity choices that are seen as the norm. At this event presenters clarified the nature of the obesity problem and the global reach of its implications, and, more hearteningly, explored promising alternatives for stopping the epidemic’s spread. To successfully limit the detrimental effects of obesity worldwide, all of these efforts will require a great deal of collaboration between public health experts, government officials, national governments, basic science researchers, and community representatives.

Use the tabs above to find a meeting report and multimedia from this event.


Presented by:

  • Johns Hopkins Bloomberg School of Public Health
  • The Sackler Institute for Nutrition Science
  • The New York Academy of Sciences

Obesity: A Domestic Perspective

Jeanne Clark (Johns Hopkins University School of Medicine)
  • 00:01
    1. Introduction; Obesity trends in U.S.
  • 08:32
    2. Etiologies of obesity; Novel risk factors
  • 21:31
    3. Medical consequences; Treatment; Prevention
  • 27:04
    4. Summary and conclusio

Interventions — Opportunities, Successes, and Challenges

Keshia M. Pollack (Johns Hopkins Bloomberg School of Public Health)
  • 00:01
    1. Introduction; Clinical interventions
  • 06:25
    2. Schools; Communities
  • 15:21
    3. Worksites; Research examples
  • 27:25
    4. Future opportunities; Conclusio

The Global Epidemic of Obesity

Benjamin Caballero (Johns Hopkins Bloomberg School of Public Health)
  • 00:01
    1. Introduction
  • 05:22
    2. The nutrition transition; Dietary changes
  • 13:34
    3. Changes in food prices and lifestyle; Early undernutrition
  • 16:46
    4. Co-morbidities of obesity; U.N. development goals; Conclusio

Policy: The Final Frontier

Kelly D. Brownell (Yale University)
  • 00:01
    1. Introduction; Guiding philosophy; The default approach
  • 09:24
    2. Strategic science; Liquid calories; The tax disincentive
  • 28:48
    3. Smart Choices case study; The change agents; Conclusio

Panel Discussion

Moderator: Robert S. Lawrence (Johns Hopkins Bloomberg School of Public Health)
  • 00:01
    1. Introduction and overview by Robert Lawrence
  • 07:15
    2. The 2012 farm bill; Food safety
  • 16:40
    3. Optimal defaults; For-profit initiatives
  • 24:53
    4. Beverage tax; Subsidy programs; Obesity stigma
  • 35:23
    5. Affordability of fruits and vegetables; One-on-one approaches
  • 43:20
    6. Respect for one's body; Policy and pharma; Calories in and out
  • 57:03
    7. Health risks of sweeteners; Conclusio

Super-sized World: The Global Obesity Epidemic

Michael J. Klag (Johns Hopkins Bloomberg School of Public Health)
  • 00:01
    1. Introduction and overview
  • 06:30
    2. Determinants of health; Conclusio


CDC Topic Page for Obesity
Contains information about overweight and obesity in the U.S. as well as data and statistics.

Healthy People 2010
Healthy People provides science-based, 10-year national objectives for improving the health of all Americans.

The official journal of the Obesity Society.

The Obesity Society
The leading scientific society dedicated to studying obesity.

The New York Obesity Nutrition Research Center
The New York Obesity Nutrition Research Center aims to reduce the incidence of obesity and related diseases with basic research, clinical research, epidemiology and public health, patient care, and public education.

Journal Articles

Kelly D. Brownell

Andreyeva T, Long MW, Brownell KD. The impact of food prices on consumption: a systematic review of research on the price elasticity of demand for food. Am. J. Public Health 2010; 100(2):216-222.

Bray GA, Nielsen SJ, Popkin BM. Consumption of high-fructose corn syrup in beverages may play a role in the epidemic of obesity. Am. J. Clin. Nutr. 2004; 79(4):537-543.

Brownell KD. Government intervention and the nation's diet: the slippery slope of inaction. Am. J. Bioeth. 2010; 10(3):1-2.

Brownell KD, Farley T, Willett WC, et al. The public health and economic benefits of taxing sugar-sweetened beverages. N. Engl. J. Med. 2009; 361(16):1599-1605.

Brownell KD, Kersh R, Ludwig DS, et al. Personal responsibility and obesity: a constructive approach to a controversial issue. Health Aff. (Millwood) 2010; 29(3):379-387.

Carroll GD, Choi JJ, Laibson D, Madrian BC, Metrick A. Optimal defaults and active decisions. Q. J. Econ. 2009; 124(4):1639-1674.

Clark C, Crockett SJ. Concern over ready-to-eat breakfast cereals. J. Am. Diet Assoc. 2008; 108(10):1618-1619; author reply 1619-1620.

Harris JL, Schwartz MB, Ustjanauskas A, Ohri-Vachaspati P, Brownell KD. Effects of serving high-sugar cereals on children's breakfast-eating behavior. Pediatrics 2011; 127(1):71-76.

Nicklas TA, O'Neil CE. Concern over ready-to-eat breakfast cereals. J. Am. Diet Assoc. 2008; 108(10):1616-1617; author reply 1619-1620.

Nielsen SJ, Popkin BM. Changes in beverage intake between 1977 and 2001. Am. J. Prev. Med. 2004; 27(3):205-210.

Thompson D, Franko DL, Barton BA. Concern over ready-to-eat breakfast cereals. J. Am. Diet Assoc. 2008; 108(10):1617-1618; author reply 1619-1620.

Benjamin Caballero

Chen L, Appel LJ, Loria C, et al. Reduction in consumption of sugar-sweetened beverages is associated with weight loss: the PREMIER trial. Am. J. Clin. Nutr. 2009; 89(5):1299-1306.

Chen L, Caballero B, Mitchell DC, et al. Reducing consumption of sugar-sweetened beverages is associated with reduced blood pressure: a prospective study among United States adults. Circulation 2010; 121(22):2398-2406.

Franco M, Diez-Roux AV, Nettleton JA, et al. Availability of healthy foods and dietary patterns: the Multi-Ethnic Study of Atherosclerosis. Am. J. Clin. Nutr. 2009; 89(3):897-904.

Li Y, Zhai F, Wang H, Wang Z, et al. [A four-year prospective study of the relationship between body mass index and waist circumstances and hypertension in Chinese adults]. Wei Sheng Yan Jiu 2007; 36(4):478-480.

Monteiro CA, Moura EC, Conde WL, Popkin BM. Socioeconomic status and obesity in adult populations of developing countries: a review. Bull. World Health Organ. 2004; 82(12):940-946.

Popkin BM, Gordon-Larsen P. The nutrition transition: worldwide obesity dynamics and their determinants. Int. J. Obes. Relat. Metab. Disord. 2004; 28 Suppl 3:S2-9.

Streatfield PK, Karar ZA. Population challenges for Bangladesh in the coming decades. J. Health Popul. Nutr. 2008; 26(3):261-272.

Jeanne M. Clark

Monasta L, Batty GD, Macaluso A, et al. Interventions for the prevention of overweight and obesity in preschool children: a systematic review of randomized controlled trials. Obes. Rev. 2010.

Ogden C & Margaret CM. June 2010. Prevalence of obesity among children and adolescents: United States, trends 1963–1965 through 2007–2008. Division of Health and Nutrition Examination Surveys.

Svetkey LP, Stevens VJ, Brantley PJ, et al. Comparison of strategies for sustaining weight loss: the weight loss maintenance randomized controlled trial. JAMA 2008; 299(10):1139-1148.

Michael Klag

Danaei G, Ding EL, Mozaffarian D, et al. The preventable causes of death in the United States: comparative risk assessment of dietary, lifestyle, and metabolic risk factors. PLoS Med. 2009; 6(4):e1000058.

Longenecker JC, Coresh J, Powe NR, et al. Traditional cardiovascular disease risk factors in dialysis patients compared with the general population: the CHOICE Study. J. Am. Soc. Nephrol. 2002; 13(7):1918-1927.

Ramachandran A, Snehalatha C, Kapur A, et al. High prevalence of diabetes and impaired glucose tolerance in India: National Urban Diabetes Survey. Diabetologia 2001; 44(9):1094-1101.

Wang Y, Chen X, Klag MJ, Caballero B. Epidemic of childhood obesity: implications for kidney disease. Adv. Chronic Kidney Dis. 2006; 13(4):336-351.

Wang H, Wang Z, Yu W, Zhang B, Zhai F. [Changes of waist circumference distribution and the prevalence of abdominal adiposity among Chinese adults from 1993 to 2006]. Zhonghua Liu Xing Bing Xue Za Zhi 2008; 29(10):953-958.

Keshia M. Pollack

Bleich SN, Pollack KM. The publics' understanding of daily caloric recommendations and their perceptions of calorie posting in chain restaurants. BMC Public Health 2010; 10:121.

Pollack KM. An injury prevention perspective on the childhood obesity epidemic. Prev. Chronic Dis. 2009; 6(3):A107.

Pollack KM, Cheskin LJ. Obesity and workplace traumatic injury: does the science support the link? Inj. Prev. 2007; 13(5):297-302.

Pollack KM, Sorock GS, Slade MD, et al. Association between body mass index and acute traumatic workplace injury in hourly manufacturing employees. Am. J. Epidemiol. 2007; 166(2):204-211.

Pollack KM, Samuels A, Frattaroli S, Gielen AC. The translation imperative: moving research into policy. Inj. Prev. 2010; 16(2):141-142.

Pollack KM, Frattaroli S, Whitehill JM, Strother K. Youth Perspectives on Street Outreach Workers: Results from a Community-Based Survey. J. Community Health 2010.

Keynote Speaker

Michael J. Klag, MD, MPH

Johns Hopkins Bloomberg School of Public Health
e-mail | website | publications

Michael J. Klag, an internationally known expert on the epidemiology and prevention of cardiovascular and kidney disease and a Johns Hopkins faculty member since 1987, became Dean of the university's Bloomberg School of Public Health on Sept. 1, 2005. Klag previously served as the David M. Levine Professor of Medicine in the university's School of Medicine, with joint appointments in the Bloomberg School's Department of Epidemiology and Department of Health Policy and Management. He also was Vice Dean for Clinical Investigation in the School of Medicine.

Klag is a 1974 graduate of Juniata College and earned his medical degree from the University of Pennsylvania in 1978. After completing residency and chief residency in internal medicine at the State University of New York Upstate Medical Center, he served in the U.S. Public Health Service. In 1984, he came to Johns Hopkins as a general internal medicine fellow and earned a master of public health degree in 1987 from what was then known as the Johns Hopkins School of Hygiene and Public Health. He was a founding member and Interim Director of the university's Welch Center for Prevention, Epidemiology and Clinical Research; Director of the Division of General Internal Medicine in the School of Medicine; and, in 2000–2001, interim physician-in-chief of The Johns Hopkins Hospital and Interim Director of the Department of Medicine in the School of Medicine. He has published more than 120 peer-reviewed articles and is a fellow of the American College of Physicians.


Kelly D. Brownell, PhD

Yale University
e-mail | website | publications

Kelly Brownell is Professor of Psychology, Epidemiology and Public Health at Yale University, and Director of the Rudd Center for Food Policy and Obesity. TIME magazine listed Brownell among "The World's 100 Most Influential People" as one "whose power, talent or moral example is transforming the world." A member of the Institute of Medicine since 2006, Brownell served as President of the Society of Behavioral Medicine, Association for the Advancement of Behavior Therapy, and the Division of Health Psychology of the American Psychological Association. His awards include the Graduate Mentoring Award from Yale, the Association for Psychological Science's James McKeen Cattell Fellow Award, the award for Outstanding Contribution to Health Psychology from the American Psychological Association, the Purdue University Distinguished Alumni Award, and the Rutgers University Lifetime Achievement Award. In addition, Brownell is the author of 14 books and more than 300 scientific articles and chapters.

Benjamin Caballero, MD, PhD

Johns Hopkins Bloomberg School of Public Health
e-mail | website | publications

Benjamin Caballero is Professor of International Health at the Bloomberg School of Public Health, and Professor of Pediatrics at the School of Medicine, Johns Hopkins University. He has 20 years of experience as a scholar, researcher, and leader in the area of child health and nutrition. He obtained his MD from the University of Buenos Aires and his PhD (in neuroendocrine regulation) from MIT. Caballero started his faculty career at Harvard Medical School and moved to Johns Hopkins in 1990 to found the Center for Human Nutrition.

Jeanne Clark, MD, MPH, FACP

Johns Hopkins University School of Medicine
e-mail | website | publications

Jeanne Clark is an Associate Professor of Medicine and Epidemiology and a Core Faculty member in the Welch Center for Prevention, Epidemiology, and Clinical Research, within the Division of General Internal Medicine at The Johns Hopkins School of Medicine. She holds a joint appointment in the Department of Epidemiology at The Johns Hopkins Bloomberg School of Public Health. She obtained her MD from UMDNJ–Robert Wood Johnson Medical School and did her residency in Internal Medicine at Dartmouth-Hitchcock Medical Center after which she completed a fellowship in General Internal Medicine at Johns Hopkins and subsequently joined the faculty there in 2000. Clark's research focuses on the epidemiology and treatment of obesity and obesity-related consequences, including diabetes and nonalcoholic fatty liver disease. She is involved in several large, NIH-funded, multicenter, randomized clinical trials of lifestyle interventions to treat obesity and prevent its consequences.

Keshia M. Pollack, PhD, MPH

Johns Hopkins Bloomberg School of Public Health
e-mail | website | publications

Keshia Pollack is assistant professor of Health Policy and Management and the Leon S. Robertson Faculty Development Chair in Injury Prevention at the Johns Hopkins Bloomberg School of Public Health and a core faculty member of the Johns Hopkins Center for Injury Research and Policy and Center for Health Disparities Solutions.

Pollack's research focus is on the development of policies that create safe and healthy environments. She is specifically interested in preventing injuries related to occupation, obesity, sports/physical activity, and the built environment, as well as understanding how they disproportionately affect vulnerable populations. Her current research in obesity prevention includes studies exploring injury risks and hazards encountered by children along routes to schools and formulating effective obesity prevention policies. She is also developing a food-centered intervention to reduce cardiac risk factors, including obesity, for firefighters. Before joining Johns Hopkins, Pollack was a fellow at the University of Pennsylvania and the Robert Wood Johnson Foundation where she participated in grantmaking, program development, and evaluations for childhood obesity, violence, and health issues affecting vulnerable populations.

Keith Mulvihill

Keith Mulvihill is a freelance writer based in Manhattan. He worked as an environmental chemist before becoming a science writer. He covers a wide range of topics and has contributed to a variety of newspapers, magazines and websites.


  • Johns Hopkins Bloomberg School of Public Health
  • The Sackler Institute for Nutrition Science
  • The New York Academy of Sciences

Michael J. Klag, Johns Hopkins Bloomberg School of Public Health
Jeanne Clark, Johns Hopkins University School of Medicine


  • In 2005 approximately 250,000 deaths in the U.S. were directly attributed to overweight and obesity.
  • In 2000, 40% of people in India over the age of 50 had either impaired glucose tolerance or type 2 diabetes. 
  • Obesity increases the risk for heart disease, type 2 diabetes, stroke, certain types of cancer, liver and gallbladder disease, osteoarthritis, and respiratory problems.


Once considered a problem only in high-income countries, overweight and obesity are now dramatically on the rise in low- and middle-income countries, particularly in urban settings. Globally, there are more than 1 billion overweight adults and about 300 million of them are obese, according to the World Health Organization. On December 9, 2010, academics, public health experts and industry leaders came together at a symposium called Super-Sized World: The Global Obesity Epidemic, held by the New York Academy of Sciences, the Sackler Institute for Nutrition Science, and the Johns Hopkins Bloomberg School of Public Health, to discuss the latest science and policy initiatives to combat this alarming world-wide phenomenon.

Obesity is a major cause of disease and death, noted keynote speaker Michael Klag of Johns Hopkins Bloomberg School of Public Health. Klag presented data revealing that in the United States in 2005 there were approximately 250,000 deaths directly attributed to overweight and obesity. Population data from India taken in 2000 shows that 40% of people over the age of 50 have either impaired glucose tolerance or type 2 diabetes, which can increase risk of death. Given the increasing number of people who are overweight and obese, public health experts and policy makers are concerned about what the future may hold as the effects of these rising numbers are felt: obesity is a major contributor to the global burden of chronic disease and disability as a risk factor for type 2 diabetes, cardiovascular disease, hypertension, stroke, and certain forms of cancer. "We should be worried about this right now," said Klag, "We are in an epidemic of chronic disease, and obesity is one of the leading reasons."

Obesity primer

In her talk "Obesity—A Domestic Perspective," Jeanne Clark, from Johns Hopkins University School of Medicine, presented an overview of how public health professionals identify and study obesity in populations. She also briefly summarized the current understanding of the various causes of obesity.

How obesity is measured

When physicians and public health experts speak about overweight and obesity they are generally referring to ranges of weight that are considered healthy for people of a given height. Body Mass Index (BMI) is the primary measurement used by public health experts to judge whether or not an individual is under- or overweight. Specifically, BMI is a calculation of a person's weight in kilograms divided by the square of his or her height in meters, and a BMI of 30 or higher is considered obese.

What does BMI mean in practical terms? For example, a man who is 5'11" and weighs 215 pounds would yield a BMI of 30. A woman who is 5'4" and weighs 175 pounds would have a BMI of 30 or more. In children a classification of "At risk for overweight" is given for those at or exceeding the 85th percentile of weight for age and sex and "overweight" for those at or exceeding the 95th percentile of weight for age and sex (see the calculator).

Researchers believe that fat deposits in the liver may be the cause of metabolic imbalances in people who are clinically obese. Above, MRI scans reveal fat deposits in two different subjects: the woman on the left is clinically obese. (The whitish areas are fat deposits.)

It is important to note that although BMI correlates with amount of body fat, BMI does not directly measure body fat. Other methods of estimating body fat and body fat distribution include Dual Energy X-ray Absorptiometry (DEXA), magnetic resonance imaging (MRI) and underwater weighing. In large scale studies, however, BMI is often the most practicable metric for obesity and overweight. As Clark affirmed, "I think for population studies and for public health, BMI is the most feasible measure."

Etiologies of obesity

In general, energy balance—the ratio of energy consumed to energy used—dictates how much fat a person's body has, noted Clark. The body works very hard to stay at equilibrium and the process involves a lot of different systems. Disruption of energy balance can have a variety of causes, separable into two categories: genetic and environmental factors. Genes and genetic variation can account for up to 80% of the variation in the amount of fat a person retains relative to others with the same energy balance. There are known single gene (monogenic) disorders linked to some forms of obesity, but they are very rare. Polygenic obesity on the other hand is more likely to account for a larger percentage of obesity. "A lot of little changes in genes that impedes the body's ability to efficiently burn calories" are probably involved in people's increased susceptibility to obesity, said Clark.

Environmental factors also play a big role, and researchers believe these factors interact with a person's genes. In the United States, the vast majority of people live in an environment of abundant, cheap, high-fat, calorie-dense foods. Decreased physical activity can also contribute to high rates of obesity.

Another crucial factor is the fetal environment, said Clark. Epigenetic changes that may result from a lack of nutrients or calories during fetal development may later contribute to weight gain and obesity in an environment of excess calorie consumption after birth. "Those genetically at risk will respond differently than those who might be resistant [to weight gain]," she said.

Clark also touched upon a list of novel risk factors that have limited scientific evidence to support them at this stage, but which are still areas worthy of further research and discussion. Some of these areas include fructose consumption, sleep deprivation, maternal smoking, and maternal weight.

Medical consequences and treatment of obesity

Research has shown that myriad diseases are related to being overweight and obese. As one's weight increases so, too, does the risk for heart disease, type 2 diabetes, stroke, certain types of cancer, liver and gallbladder disease, osteoarthritis, and respiratory problems.

Clark ended her presentation by emphasizing that current treatment regimens are inadequate for the magnitude of the problem that public health professionals are facing both in the U.S. and globally. She noted that even highly motivated individuals enrolled in weight loss trials that employ lifestyle modifications to diet and exercise might only see a 5%-10% weight loss. And in most cases, half or more than half of weight lost is eventually regained during the months following the intervention.

Likewise, weight loss drugs often yield success in the short run, but when people stop taking the drugs the weight comes back. Moreover, most insurance companies do not cover such drugs so rates of use remain low. Bariatric surgery (stomach stapling) has been shown to be very effective, but it has the potential for serious adverse side effects so its use is restricted to the most extreme cases: those individuals with a BMI of 40 or more (or those with a BMI of 35 who have co-morbid conditions). In 2007 there were roughly 63,000 bariatric surgeries conducted in the United States but more than 17 million people had a BMI of 40 or more. Hence, this surgery is not having a significant impact on reducing obesity on national level.

Jeanne Clark, Johns Hopkins University School of Medicine
Benjamin Caballero, Center for Human Nutrition, Johns Hopkins Bloomberg School of Public Health


  • In 2009, thirty-three states had a prevalence of obesity equal to or greater than 25%, and nine of these states had a prevalence of obesity equal to or greater than 30%.
  • In the U.S., non-Hispanic black women and Mexican American women have the highest rate of obesity.
  • By 2030, experts estimate that almost 80% of the world’s urban population is going to be in developing countries. 
  • Globally, the cost of soft drinks has been decreasing while the cost of fresh fruits and vegetables has been on the rise.

Obesity in U.S. adults and children

Jeanne Clark also presented data about the relative obesity rates in different populations in the United States. In 1985, the Centers for Disease Control and Prevention launched the Behavioral Risk Factor Surveillance System (BRFSS), a state-based system of health surveys that generate information about health risk behaviors, clinical preventive practices, and health care access and use primarily related to chronic diseases and injury. Among the various data collected, the BRFSS surveys yielded information about obesity. During the past 20 years there has been a steady and dramatic increase in obesity rates in the United States. According to the BRFSS, in 2009 only Colorado and the District of Columbia had a prevalence of obesity less than 20%. Thirty-three states had a prevalence equal to or greater than 25%, and nine of these states had a prevalence of obesity equal to or greater than 30%.

Data from the National Health and Nutrition Survey (NHANES) reach back to the mid-1970s and show that the national prevalence of overweight and obesity has risen from 47% and 15%, respectively, in 1976 to 67% and 35% in 2006.

Clark noted that there are differences in obesity patterns with regard to ethnicity and gender. Specifically non-Hispanic black women and Mexican American women have the highest rate of obesity relative to other populations sorted by ethnicity and gender. "This is not to point out that race or gender is really the main risk factor," she said. However, she explained that Mexican American and non-Hispanic black women are the two groups with the highest level of poverty and the least access to health care in the U.S.

Data for children are often even more troubling, since health care professionals are seeing chronic diseases, such as fatty liver disease, occurring in children at younger ages. Obesity in children has steadily increased from 1963 to 2008.

The global epidemic of obesity

Although it is widely known that obesity is a major and growing problem in the United States, many policy makers may not be aware that obesity is increasing even faster in many developing countries. A 2004 study shows that obesity rates in China, Brazil, Morocco, Thailand, and Mexico are all increasing at a faster pace than rates in the U.S. In his talk, "Obesity—A Global Perspective," Benjamin Caballero of the Center for Human Nutrition at Johns Hopkins Bloomberg School of Public Health summarized some of the issues that public health experts and policy makers face when dealing with obesity as a global disease.

The first report that identified global obesity as an epidemic was released by the World Health Organization in 1997. "This is a field in which we are still developing ideas and concepts" about how to deal with global obesity, said Cabellero. Among the top ten countries in the world with increasing rates of obesity, seven are developing countries. Similarly, a World Bank report indicates that countries with medium-low and medium-high economic development levels are showing faster increases in obesity than high-income level countries.

"Clearly we now have sufficient evidence that the magnitude of this problem not only affects all countries, but it is particularly serious in developing countries," Caballero stressed.

There are some characteristics of the obesity epidemic in developing countries that are similar to features of the US epidemic, but there are also several important differences. In Brazil, obesity is now common in both high and low socioeconomic groups. However, in Brazil and in many developing countries, populations of lower socio-economic status have high prevalence of both under-nutrition, both low calorie intake and nutrient-deficient calorie intake, and over-nutrition, excess calorie consumption. Researchers estimate that around the world, millions of undernourished children are living among millions of adults who are overweight.

There have been sweeping changes in food prices in the U.S. and abroad: the decreasing cost of carbonated, non-alcoholic beverages and the increasing cost of fresh fruits and vegetables.

This phenomenon is termed the Nutrition Transition and an important cause of this problem is the shift in world population distribution. A report by the United Nations predicts that by 2025 a large portion of population growth will live in urban areas, and by 2030 almost 80% of the world's urban population is going to be in developing countries. This is of concern to public health experts because many lifestyle characteristics associated with urban living are strongly associated with poor health outcomes, including obesity.

Dietary changes

As more of the world's population call urban areas home, researchers are predicting that resulting dietary changes will have sweeping consequences. Changes in food type, availability, and cost will greatly influence eating behaviors. The consumption of calories per capita is expected to continue to increase, bringing the daily consumption per individual close to 3000 kilocalories by the year 2030. But total caloric intake is just one part of the story. Perhaps most alarmingly, noted Caballero, world consumption of vegetable oil will increase (fueled by lower prices). He also predicted that the growth in the processed food market is likely to continue to be strong in upper and low-middle income countries.

Beverage intake by income level has changed dramatically since the early 1990s. Not only did people drink fewer beverages back before the 1990s, but, as expected, people with higher incomes consumed more than those with lower incomes. Today, not only has consumption increased dramatically overall, but people with lower incomes now consume more than double the volumes drunk by wealthier people. Troubling is the fact, too, that sweeping changes in food prices here in the U.S. and abroad show a strong trend toward a decreasing cost of carbonated, non-alcoholic beverages and an increasing cost of fresh fruits and vegetables, bringing calorie intake further out of balance with nutrient intake.

Prediction (in millions) of worldwide diabetes prevalence in 2030.

Caballero also echoed Clark's sentiments about another problem that public health researchers are just beginning to understand: people who experience undernourishment early in life (either in utero or in the first few years of life) who then consume excess calories (relative to what they use) as adults. This pattern is associated with a higher risk of obesity, he said. "This is like a time bomb for many developing nations because they still have large populations of children that are undernourished," said Caballero, so developing nations will be forced to grapple with both ends of the spectrum at once.

Caballero ended his talk by highlighting worldwide trends in type 2 diabetes noting that estimates predict that by 2030 India will have 79 million people with the disease, and China and the U.S. are not far behind with 42 million and 30 million people, respectively. In light of these predictions "It is critical that we begin to eliminate some of the most fundamental risks factors for excessive weight gain," said Caballero.

Keshia M. Pollack, Johns Hopkins Bloomberg School of Public Health
Kelly D. Brownell, Rudd Center for Food Policy and Obesity, Yale University


  • The percentage of the U.S. population getting the recommended level of physical activity from 1986 to 2000 is largely unchanged.
  • A national penny-per-ounce tax on of sugar-sweetened beverages could reduce health care costs by $50 billion and generate $150 billion in revenue over 10 years. 
  • Workplace, school, and community interventions are helping public health experts shape policy.

Finding interventions that have impact

Public health experts have been waging a battle against obesity for decades, and their efforts have intensified in the last 10 years. In 2003, Richard Carmona, then U.S. Surgeon General, campaigned for greater action against obesity among Americans. More recently, First Lady Michelle Obama launched the Let's Move campaign to help raise awareness and curb childhood obesity.

How best to respond to the growing waistlines in the United States and around the world has been a subject of debate for many years. Keshia M. Pollack of Johns Hopkins Bloomberg School of Public Health focused her presentation "Interventions: Successes, Opportunities, and Challenges" not only on the types of possible interventions but also on who should spearhead them. Because the causes of obesity are various, Pollack says she favors a collaborative approach on the part of medical professionals, the government, community groups, and individuals when it comes to combating the problem.

"We know that we are most effective when we focus on multifaceted, comprehensive interventions that address lifestyle changes," she said. "If we are going to address obesity we need to target multiple levels of influence."

Perhaps most critical will be the ability of public health experts to identify all of the factors that influence the everyday lives of the people or groups programs are trying to help. Pollack presented an overview of the various types of obesity interventions, but her take-home message was that multiple methods of action are more likely to yield successes than are efforts focused on single methods of action.

Schools, for example, offer a great place for obesity interventions since children spend a great deal of time at school and many eat one or two meals there. The school environment also provides many opportunities to influence caloric intake and physical activity levels. New efforts may include structuring physical education into the school day or offering non-traditional types of activities, for example non-competitive sports such as dancing. Even though particular efforts to give parents BMI report cards about their children have met some resistance, Pollack asserted that broadly speaking, "we do know that if we deliver information about body mass index to parents in an effective way it does help them to understand those potential health risks."

Pollack discussed numerous opportunities for straightforward interventions within communities and workplaces. She also talked about two of her current research projects, one of which involves the impact of an urban environment on children's outdoor play areas and on their ability to walk to and from school. Her study has so far evaluated a total of 360 children, ages 8 to 13, from 6 different Baltimore, Maryland, area schools. Analysis of the data revealed useful information about how children perceive the safety of their environment and how violence affects their ability to walk to school or to play in local playgrounds or parks. The findings have already had many implications for policymaking. One outcome of the study is that Pollack is working with colleagues in Baltimore to create "walking school buses," small groups of children who walk to school with one or more adults.

A second on-going research project, called the Firefighter Food Intervention Research and Evaluation (FFIRE) Study, is a workplace intervention that aims to help firefighters learn about nutrition, reduce caloric intake, and prepare healthier meals. So far, the research team has identified peer advocates to provide support in the fire station for study participants, has provided tailored behavioral and nutrition information and counseling, and has even given cooking demonstrations.

In her closing statements, Pollack said that that the primary question for public health experts is: How do we make the environment less toxic? The answer lies, for Pollack, in pro-health policymaking: "With emerging and innovative policies we will eventually tackle this epidemic," she explained.

New approaches: shaping policy & opinion

Devising workable policy solutions that begin to lessen the obesity epidemic has proven to be a tall order for public health professionals. The goal of effecting major behavioral changes, such as consuming fewer calories and getting more exercise, has proven to be far more elusive than many experts would have predicted. In his presentation "The Final Frontier: Is There the Courage to Change Policy?", Kelly D. Brownell, a soda tax advocate and director of the Rudd Center for Food Policy and Obesity at Yale University, noted that despite widely disseminated studies and news reports about the importance of exercise as it relates to health and obesity, the percentage of the U.S. population getting the recommended level of physical activity from 1986 to 2000 is largely unchanged. The same can be said for the percentage of American adults and children eating the recommended daily allowance of fruits and vegetables: after decades of various educational programs, increases in consumption of these vital nutrient sources have been virtually non-existent.

"It's apparent that the way we have been approaching this problem, as a default, hasn't been working so well," assessed Brownell. "Can we take a new approach that might contribute to more positive outcomes?"

Are there alternatives to simply focusing on individuals through education? Would it be possible to make economic changes or to leverage the government's legislative authority to make regulatory changes? Brownell went on to suggest that making changes in what he termed "optimal defaults" may produce more positive outcomes than imploring people to change their habits: in essence the goal would be to increase the likelihood that people are exposed to a set of conditions that promote healthy behavior over unhealthy behavior. In analogous situations, "optimal defaults" have been achieved, for instance, by having corporations automatically enroll new employees into a pension plan or by requiring individuals to opt out of automatic organ donation enrollment as is customary in some countries (Austria, Belgium, and France, to name a few). In both examples the onus is on the individual to opt out, creating positive enrollment levels that are near 100%.

In light of these examples, Brownell asked meeting attendees to consider what types of food and physical activity defaults we have in the U.S. and whether they can be changed in a way that may help with the fight against obesity.

"My belief is that the defaults people are exposed to are really pretty catastrophic," he said. The list of bad defaults includes large portion sizes, too much access to unhealthy foods, too little access to healthy foods, and the many millions of dollars being spent on the marketing of junk food.

Brownell then critiqued the ways in which scientific research is commonly conducted (termed by Brownell as programmatic science) in the United States, noting that current overarching methodologies do not automatically lead to positive changes in public health policy. He then introduced the concept of strategic science—a method of conducting scientific research with an end goal that is more broadly focused on affecting or driving public policy, and not just on advancing scientific theory. With a "strategic science" approach, Brownell said he envisions scientific research that is conducted at a more rapid pace and with an audience that is not composed solely of other scientists but also of policymakers. Strategic science, as opposed to more traditional programmatic scientific pursuits, according to Brownell, may be a better means of harnessing research in an effort to help change public policy.

As an example of strategic science, Brownell pointed to a study that he co-authored that aimed to dispel the notion that children will only choose high sugar breakfast cereal. According to the new findings (Harris et al., 2010) children will eat lower sugar content breakfast cereal when given the option.

Brownell then turned to the topic of sugar-sweetened beverages, remarking that the high-calorie drinks play a role in contributing to the obesity epidemic. The number of calories that Americans get from liquids has gone up in the United States and around the world. One contributing factor is the simple fact that consumer prices for soft drinks from 1985 to 2000 increased by 20% while during the same time the price of fruits and vegetables rose by 117%. Recent marketing trends have also seen sugar-sweetened beverages marketed with implied health benefits. In light of these and other concerns, Brownell reiterated his longstanding proposal of a tax on sugar-sweetened beverages as one means of dealing with the obesity problem.

17 states and 2 American cities (highlighted in red here) have filed soda tax legislation during the past two years.

According to Brownell, there are many reasons to focus on sweetened beverages over other culprits of poor nutrition: these drinks are the greatest source of added sugar in the American diet, they are devoid of nutritional value, sugar may have addictive properties, people who drink sugar beverages often fail to compensate for the extra calories by decreasing calorie intake from other sources, and scientific evidence links sugar-sweetened beverage consumption to a risk for obesity, type 2 diabetes, and other negative health outcomes.

Brownell remarked that a tax, perhaps a penny per ounce on any beverage with added sugar, could reduce consumption of sugary beverages. Studies of consumer product price elasticity (a product's saleability as its price increases or decreases) have shown that consumers may be less likely to purchase sugar-sweetened beverages if they cost more.

Brownell estimates that a national penny per ounce tax would decrease consumption by up to 23 percent; reduce health care costs by $50 billion over 10 years and generate $150 billion in revenue over 10 years. A state tax could generate hundreds of millions of dollars in revenue, and money raised by the tax could be spent on public health efforts to fight obesity.

In closing, Brownell noted that there is wide agreement among health officials and nutrition experts that people should reduce consumption of sugar-sweetened beverages, but, he qualified, "not everybody believes that a tax is the best way to go about that."

Brownell explained that other strategies do not seem to be working. "How far down the field can you move just by doing education, and do you need something where you change the fundamental economics of the sale of the product in a way that would benefit public health?" he queried.

"The obesity problem is clearly out of control in the U.S. and around the world," said Brownell, "There are a lot of things we can do about it if we have the political will to do it, but this means changing systems, it means taking on the food industry, and it means thinking about the problem in a much different way than we traditionally have been doing."