News Release

Tuesday, May 1, 2018

Panel calls for improvements in research on natural experiments to combat the obesity epidemic

Obesity is a major contributor to serious health conditions in children and adults.

An independent panel convened by the National Institutes of Health outlined several recommendations to improve research to end the obesity epidemic, emphasizing the need for an expanded approach to obesity research. They note that additional methods are needed to assess obesity prevention interventions occurring at the community level.

Obesity is a major contributor to serious health conditions in children and adults. The prevalence of obesity has grown rapidly in the last three decades. In 2014, more than one-third (39.8 percent) of U.S. adults and 18.5 percent of U.S. children and young adults met the definition of obesity.

There is an urgent need for evidence-based approaches to help people achieve and maintain a healthy weight. Yet, because multiple factors such as lifestyle, socioeconomics, and the environment contribute to obesity, maintaining a healthy weight remains a difficult condition to study.

Actions such as financial incentives for healthier foods, community-based physical activity programs, or construction of separated bike lanes that are designed to change real-world environments present an exciting opportunity to evaluate “natural experiments” in obesity. However, incomplete development and lack of standardization in study designs, data collection methods, and statistical approaches present significant challenges.

“The obesity epidemic in the United States has not been reversed. It is essential that researchers examine the status of the methods used to assess natural experiments to reduce obesity and focus on areas in which these methods could be improved to advance the field,” said Dr. Karen Emmons, professor of social and behavioral science at Harvard T.H. Chan School of Public Health, Boston.

To help strengthen evidence from studies of natural experiments to reduce obesity, NIH convened the Pathways to Prevention Workshop: Methods for Evaluating Natural Experiments in Obesity on December 5–6, 2017. A panel of independent experts moderated the workshop and developed a report. The report includes recommendations to enhance data systems and integration, standardize measurement of obesity-related outcomes, and improve methods for study design and analysis. The panel also recommends increased training and community engagement in obesity research, as well as funding for long-term follow-up on promising natural experiments.

“Increased communication between researchers and policymakers involved with obesity research and collaborative partnerships for data sharing purposes is necessary to assist in both prioritizing obesity research and driving change,” said Dr. Emmons, workshop and panel chair.

The panel’s final report incorporates its assessment of the workshop’s systematic review of the scientific evidence, expert presentations, audience input, and public comments. The report is an independent report and not a policy statement of NIH or the federal government.

The workshop was co-sponsored by the NIH Office of Disease Prevention; National Cancer Institute; National Heart, Lung, and Blood Institute; and National Institute of Diabetes and Digestive and Kidney Diseases. The systematic evidence review was prepared by the Johns Hopkins Evidence-based Practice Center, Baltimore, under contract to the Agency for Healthcare Research and Quality.

The five-member panel included experts in the fields of family medicine, statistics, health education, prevention and community health research, and epidemiology. Panel member biographies, an archived NIH VideoCast of the workshop, and additional resources are available on the ODP website.

The Office of Disease Prevention assesses, facilitates, and stimulates research in health promotion and disease prevention in collaboration with the NIH and other public and private partners, and disseminates the results of this research to improve public health. For more information about the ODP, visit

The National Cancer Institute leads, conducts, and supports cancer research across the nation to advance scientific knowledge and help all people live longer, healthier lives.

The National Heart, Lung, and Blood Institute provides global leadership for a research, training, and education program to promote the prevention and treatment of heart, lung, and blood disorders and enhance the health of all individuals so that they can live longer and more fulfilling lives.

The National Institute of Diabetes and Digestive and Kidney Diseases, part of NIH, conducts and supports basic and clinical research and research training on some of the most common, severe, and disabling conditions affecting Americans. The Institute’s research interests include: diabetes and other endocrine and metabolic diseases; digestive diseases, nutrition, and obesity; and kidney, urologic, and hematologic diseases. For more information, visit

About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit

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