Questions and Answers
Q1: What is the problem and why is it a public health issue?
A1: Obesity is a problem of epidemic proportions increasing the risk for disease, lowering life expectancy and raising US health care costs to over $150 billion annually. The medical cost to treat an obese individual is $1,400 more per year than someone who is a healthy weight. Many leading causes of preventable death, including heart disease, stroke, type 2 diabetes and many types of cancer are often associated with obesity. In fact, according to the Lancet, obesity reduces life expectancy on average by six to seven years, and is considered by the WHO to be the fifth leading cause of death worldwide.
Q2: How is overweight and obese classified?
A2: A Body Mass Index (BMI) between 25.0 and 29.9 classifies overweight; obese is a BMI of 30.0 or above.[i] To be classified as obese, an adult must have a body mass index (BMI) of 30 or higher or weigh 20 percent or more above his or her normal weight. For adults, a BMI of 18.5 to 24.9 indicates normal weight. To determine BMI for children and adolescents, age-and sex-specific percentiles for BMI must be used rather than the BMI numbers for adults, because children’s bodies change as they age and are different between boys and girls. There are recognized drawbacks to the use of BMI, such as penalizing athletes because muscle weighs more than fat and not recognizing that women tend to have more body fat than men. Nonetheless, BMI remains one of the most widely used measurements to determine overweight and obesity for both individuals and the population.
Q3: What factors cause obesity?
A3: According to the US Surgeon General’s call to action, the primary factors of obesity and overweight are too many calories and/or lack of physical activity. In addition, genetic, metabolic, behavioral, environmental, cultural, and socioeconomic factors are known contributors to an individual’s body weight. Behavioral and environmental influences provide the greatest opportunity for actions and interventions designed for prevention and treatment.
Q4: Is obesity equally spread throughout all segments of the population?
A4: No. Much like many other socially-constructed health outcomes, obesity is more common among certain racial and ethnic minority groups and among people of lower socioeconomic status. Recent nationally representative data on adult obesity indicate that 49.5% of non-Hispanic black Americans are obese compared to 34.3% of non-Hispanic white Americans. Similar disparities are evident for children and adolescents.
Q5: What is the global burden of obesity?
A5: “Globesity” is an important topic of conversation in the world of global health as obesity occurs alongside malnutrition in developing nations. Far from just a disease of the developed world like the US and Western Europe, obesity has now reached pandemic proportions and impacts individuals in many places around the world, including in China, India, and South Africa. Approximately 1 billion people worldwide are overweight or obese, and the proportion for children is 1 in 10.
Q6: What informs the food choices that people make?
A6: Research has shown consistently that taste, cost, and convenience are the dominant factors that shape food behavior. For some people, health and nutrition concerns come into play, but this is secondary to the dominant driving forces. The choices we make are shaped by the choices we have. Individual behaviors – smoking, diet, drinking, and exercise – matter for health. But making healthy choices isn’t just about self discipline. Some neighborhoods have easy access to fresh, affordable produce; others have only fast food joints and liquor and convenience stores. Low-income neighborhoods are 4 times more likely to have convenience stores, and half as likely to have supermarkets. They are also less likely to have fruit and vegetable markets and more likely to have liquor stores.
Q7: Aren’t individuals responsible for their own weight?
A7: Individual choices occur within a broader setting of systems and environments, as illustrated through the social-ecological model. While an individual ultimately must make choices about what to eat, those choices are very much shaped by the overall food environment, from interpersonal systems likes friends and family members to public policy which impacts food costs and availability.
Q8: What is the genetic component to the obesity epidemic?
A8: While body mass index appears to be highly heritable, most experts agree that increases in obesity in the past decades are a result of interactions between genes and the environment. We know that obesity can be caused by a few very rare gene defects. We also know that some genes may be more likely to cause people to become overweight, but few of these have been identified. Having a higher genetic risk for obesity does not mean that obesity is inevitable — altering lifestyle (diet and exercise) can greatly lessen the risk. Because the span of 30 years or so is too short a time for our genetic profile to have changed, this suggests that likely (broadly considered) changes in the environment are responsible for increases in obesity.
Q9: Can schools be effective sites for anti-obesity interventions?
A9: They can be. A growing body of literature suggests that prevention/intervention efforts in schools can prevent or reduce rates of obesity. However, in order for these to be successful, school lunches are making great strides with the help of increased attention, focused initiatives, and recent legislation to improve the nutritional quality of meals and snacks offered to students at school. However, in order for these to be successful, they must be multi-modal, focusing on promoting healthy eating and activity. The lack of success for many school-based anti-obesity initiatives is a cautionary tale about well intentioned efforts that are not backed by sound evidence.
Q10: What’s happening on a state-level to address the growing obesity epidemic?
A10: Massachusetts is one of the nation’s laboratories exploring comprehensive evidence-based obesity prevention and intervention approaches aimed at meaningful, sustainable change. The Department of Public Health’s Mass in Motion (MiM) program is just one great example of a multifaceted state initiative. MiM helped push Executive Order 509 that established nutritional standards for food purchased and served by state agencies (schools, hospitals, prisons, etc.). It is also having an impact in schools with the introduction of Body Mass Index (BMI) regulation, measuring students’ BMI in public school grades 1, 4, 7 and 10 to help parents, caregivers, and others promote and monitor healthy change. On a community level, 52 towns representing 33% of the state’s population have partnered with MiM to create resources that help construct policies, systems and practices that encourage residents to “eat better and move more.”
Q11: Is there something a resource that has identified and systematically evaluated obesity prevention and control interventions to help me decide which ones are effective?
A11: Yes! The Community Guide (http://www.thecommunityguide.org/index.html) is an evidenced-based resource for many types of public health interventions, including obesity. It is overseen by a Task Force, a panel of independent, non-federal, non-compensated experts who help inform judgment about the quality of the evidence for particular intervention strategies.
- Craig Andrade, DrPH
Director, Community Health, Division of Prevention & Wellness, Mass Dept of Public Health
- Barbara Corkey, PhD
Professor, Vice Chair, Research Gastroenterology, BU School of Medicine
- Daniel Miller, PhD
Assistant Professor, BU School of Social Work
- P.K. Newby, ScD
Food Writer and Video Blogger at Play a Good Knife and Fork
- Lisa Quintiliani, PhD
Assistant Professor, SPH Community Health Sciences
- Michael Siegel, MD, MPH
Professor, SPH Community Health Sciences