Overview of the Energy Balance Working Group (EBWG)
What is “energy balance"?
Energy balance refers to the integrated effects of diet, physical activity, and genetics on growth and body weight over an individual's lifetime. Scientists are increasingly aware of the importance of understanding the effects of energy balance on the development and progression of cancer and on cancer patients' quality of life after treatment. Weight, body composition, physical activity and diet affect many physiologic systems and thus can alter the cancer process at many points.
History of the EBWG
There has been a substantial increase in knowledge linking poor weight control and sedentary lifestyles to increased risk, poorer prognosis, and poorer quality of life for many chronic diseases, including cancer. Research indicates that obesity and physical inactivity contribute greatly to increased incidence of many common cancers, adversely affect prognosis and mortality for several common cancers, and adversely affect quality of life and outcomes among cancer survivors. Research indicates that as much as 60 percent of the US population is getting insufficient regular physical activity. Almost two-thirds of the US population is now considered overweight; nearly one-half of these individuals are classified as obese. While recent data are less clear on the role of diet for many common cancers, extensive evidence indicates that diet affects multiple health outcomes, including cancer.
In 2001, the Secretary of Health and Human Services (HHS) identified overweight and obesity as a public health priority. One of the strategies to address overweight and obesity in "The Surgeon General's Call to Action to Prevent and Decrease Overweight and Obesity" was to increase research on the biological and behavioral causes of overweight and obesity. Scientists at the NCI had been studying various aspects of nutrition, physical activity, and energy balance, but the DHHS focus on overweight and obesity created a "window of opportunity" to increase the resources dedicated to increasing understanding of these issues and developing solutions to this public health problem.
Research on nutrition and physical activity at the NCI is distributed throughout several intramural and extramural divisions, including the Division of Cancer Biology (DCG), the Division of Cancer Control and Population Sciences (DCCPS), the Division of Cancer Epidemiology & Genomics (DCEG), and the Division of Cancer Prevention (DCP). In order to effectively share information, avoid duplication of efforts, and foster transdisciplinary research related to energy balance and cancer, a forum was needed to bring NCI's nutrition experts together. This led to the creation of the NCI EBWG.
NCI established the EBWG in 2002 and collaborates with the trans-NIH Obesity Task Force, which was formed in 2003. Within its first year, the EBWG assisted with the development of a chapter for the 2005 NCI Bypass Budget, "Optimizing Energy Balance to Reduce the Cancer Burden." The inclusion of energy balance in this important NCI document, along with NCI's subsequent allocation of significant financial resources to energy balance research, indicates the level of leadership support within NCI for energy balance research.
As stated in the 2005 Bypass Budget, energy balance research needs to occur in all areas of the cancer continuum. The EBWG's primary goals are:
Goal #1: Discover how body weight, physical activity, and diet, along with genetic and environmental factors, interact over a lifetime to influence the cancer process.
Examples of strategies to achieve Goal #1:
- Establishment of research centers for Transdisciplinary Research on Energetics and Cancer (TREC)
- Study of Long-Term Cancer Survivors
- Shanghai study of physical activity, diet, body weight and body composition in relation to plasma markers of cancer risk among Chinese adults
Goal #2: Monitor trends in and determinants of diet, weight, and physical activity and their cancer-related consequences across diverse populations by expanding nationwide research and health surveillance infrastructure.
Examples of strategies to achieve Goal #2:
- Development of coding, rating, and tracking systems for state obesity and physical education policies in schools
- Development of various surveys, such as a health promotion module for theHealth Information National Trends Survey (HINTS) to understand public health recommendations in physical activity and nutrition, a weight control module for the National Health and Nutrition Examination Survey (NHANES) data collection, the Hispanic Community Health Study, and support for the food and eating module in the American Time Use Survey (ATUS)
- Research on the economic factors related to diet, activity, and energy balance in at-risk populations
Goal #3: Develop improved measurement of body mass and composition, physical activity and fitness, and diet and bioactive food components through self-report measures and advances in technology for objective reference measures.
Examples of strategies to achieve Goal #3:
- Development of an automated self-administered 24-hour dietary recall system (ASA24)
- Research to improve diet and physical activity assessment
- Development of portable technology tools for real-time energy balance research
Examples of strategies to achieve Goal #4:
- Research on mechanisms of physical activity and behavior change
- Facilitation of a workshop on the feasibility of a trial to prevent breast cancer through physical activity and weight control
While a number of studies have examined single factors, such as diet, few have used a multidisciplinary approach to assess multiple factors simultaneously and integrate their effects. It is essential that future studies consider the interrelationships among these health behaviors and explore their combined and independent effects in research designs incorporating state-of-the-science measures of each. This can only be accomplished by studies that devote the attention and resources necessary to obtain detailed evaluation of body weight and composition, physical activity and diet.
Emilee Pressman, MPH
Public Health Advisor
NCI Energy Balance Working Group Coordinator
Division of Cancer Control and Population Sciences, NCI