Obesity Research Epidemiology

Why Study Obesity?

Obesity is the number one nutritional problem in the U.S. and by some estimates has now passed cigarette smoking as the most important preventable behavioral threat to health. National data suggest that what is now a widely recognized as an epidemic of excessive weight gain has in fact been evolving over nearly a 30-year period.

These facts, along with the observation that obesity prevalence continues to advance unabated in the U.S. and world-wide, have spurred an enormous interest by diverse scientific bodies and health advocacy groups in identifying strategies to address this epidemic.   

Historically, research on obesity concentrated on the biological origins of individual differences in fatness. Recent population trends, however, have underscored the fact that biological susceptibility is very widespread and, thus, that behavioral and environmental perspectives on the problem are much needed.

Increased recognition of the importance of behavioral and environmental factors is now driving requests for research applications in the area from a growing number of funding agencies. This situation presents a golden opportunity for research groups with skills in behavioral research and education related to obesity.

Epidemiology and Obesity Research

The complexity of obesity requires a multidisciplinary research approach that encompasses studies of behavioral, environmental, and biological perspectives.

The Division of Epidemiology has a core of faculty who are internationally recognized for their research on the behavioral and environmental factors associated with obesity, and on interventions designed to prevent obesity in adult, child, and adolescent populations.

Faculty expertise includes nutrition, physical activity, behavioral intervention, community intervention, environmental intervention and health policy. More generally, the University of Minnesota has a strong obesity research base in nutrition, kinesiology, psychology, clinical medicine, the basic sciences, and other supporting fields.

Obesity Related Research

Project EAT-III: Eating Among Teens and Young Adults

Investigator: Dianne Neumark-Sztainer,  Mary Story,   John Sirard,  Melissa Nelson 
Funding Agency: NIH/NHLBI

Project EAT-III follows up on EAT-I and EAT-II to improve our understanding of what influences eating, physical activity, and weight-related behaviors in teens and young adults. To address the Project EAT-III objectives, there were two major study components.

• Follow-up study with young adults: The EAT survey was revised based on an expanded model, integrating an ecological perspective with Social Cognitive Theory. Previous Project EAT participants were contacted by mail and asked to complete the revised survey, a dietary questionnaire.
• School-based study with teens: A new group of young people are being recruited from middle schools and high schools in Minnesota. This component of the study includes in-school surveys and measurements of student height and weight, as well as measurements of peer, school, and neighborhood environments. Environmental measures are being completed by peers themselves and school personnel. Geographic Information Systems (GIS) is being used to learn about the neighborhood environment.

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New Moves: Obesity Prevention Among Adolescent Girls

Investigator: Dianne Neumark-Sztainer,   Mary T. Story
Funding Agency: NIH/NIDDK
New Moves is a school-based program designed to promote increased physical activity, healthy eating behaviors, and a positive self-image among sedentary adolescent girls at risk for overweight. It is being offered to high-school girls for credit during school hours as an alternative to the regular physical education program. The program includes physical activity, nutritional guidance, social support, individual counseling, and maintenance components. Social Cognitive Theory is being used to guide the program development, implementation, and evaluation. The intervention focuses on modifying personal, socio-environmental, and behavioral factors.

For more information on New Moves, including the curriculum and surveys, visit the New Moves website.

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Iowa Women’s Health Study (IWHS)

Investigator:   Aaron R. Folsom,   Lisa Harnack,  David R. Jacobs,  DeAnn Lazovich,  Kristin E. Anderson,  Kim Robein
Funding Agency: National Cancer Institute
Several previous studies have shown that obese women whose body fat is greater in the abdomen than in the hips are at increased risk for diabetes, hypertension, and heart disease. This 25-year study is determining whether body fat distribution is also related to risk of breast and endometrial cancer, and total mortality. A sample of 42,000 postmenopausal Iowa women completed a questionnaire and took measurements of their own bodies. The women are being followed for occurrence of cancer, using the Iowa cancer registry. Studies of diet and chronic disease occurrence also have been undertaken. Linkage to medicare records is providing new outcome data.

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Hispanic Community Health Study/ Study of Latinos – Nutrition Reading Center

Investigator:  John H. Himes,   Lisa Harnack
Funding Agency: NHLBI/NIH
HCHS/SOL is a comprehensive multi-site cohort study of 16,000 Hispanics living in the US. Adult Hispanics living in San Diego, Chicago, Miami and the Bronx NY are being followed with chief outcomes related to obesity, cardiovascular disease, and diabetes. The University of Minnesota is the Nutrition Reading Center for the study, and develops and oversees the protocols, training, and analysis of dietary intake and other nutrition-related data.

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Coronary Artery Risk Development in Young Adults Study (CARDIA)

Investigator:   Pamela J. Schreiner,    David R. Jacobs,    Lyn Steffen
Funding Agency: NIH/NHLBI
ARDIA is a longitudinal observational study designed to examine secular and age-related trends in risk factors associated with coronary heart disease (CHD). The CARDIA cohort was recruited in 1985 to be balanced on gender, ethnicity, age, and educational attainment among 18 to 30 year-olds in four U.S. communities. These participants have now been followed for 20 years to examine inter-relationships of the major risk factors for CHD in young adulthood as well as emerging risk factors. As the cohort enters middle age, coronary artery calcification will be measured to assess the development of subclinical atherosclerosis and its relationship with antecedent risk factor levels. These trends will help us to better understand the risk factor patterns leading to early disease in an age range when prevention is feasible.

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Fast Food Meals Study

Investigator:  Simone French,  Robert Jeffery,  Michael Oakes,   Mary Story
Funding Agency: National Institute of Diabetes & Digestive & Kidney Diseases
The aim of this study is to examine the effect of nutrition labeling and value size pricing on fast food menu choices.

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Television Viewing and Risk of Injury and Chronic Disease Morbidity

Investigator:  Mark A. Pereira,  Darin Erickson,  David Jacobs
Funding Agency: Pending Award from National Institutes of Health / National Institute of Aging
The CARDIA Study data will be used to evaluate the propensity that television exposure may increase the risk for intentional and unintentional injuries, as well as obesity and chronic diseases through a variety of plausible and interrelated mechanisms. We aim to explore the possibility of an interaction between televesion viewing and the hostility trait in predicting a variatey of important health outcomes over this large 20-year prospective study in Caucasians and African Americans from the four U.S. metrapolitan areas.

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Genetics of Infant Growth and Later Obesity

Investigator: Ellen W. Demerath
Funding Agency: NICHD
This project uses serial growth and maturity data from 650 subjects in the Fels Longitudinal Study who have been followed from birth to adolescence in order to examine the relationship between rapid rate of growth in infancy to later obesity risk, and to test the hypothesis that there are genetic influences on infant growth and obesity in adolescence using genetic linkage analysis and SNP association testing.

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Visceral adiposity: Genetic and environmental influences

Investigator: Ellen Demerath
Funding Agency: NIDDK
This project aims to assess abdominal visceral adipose tissue using multi-image abdominal MRI in 800 related individuals from the Southwest Ohio Family Heart Study in order to localize chromosomal regions influencing level of visceral adipose tissue and related factors in the circulation (adipokines and inflammatory cytokines).

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Novel Approaches to Weight Loss Maintenance

Investigator: Robert W. Jeffery
Funding Agency: NCI/HealthPartners Prime
Weight loss maintenance is the most critical challenge for obesity treatment. Extending treatment length can improve maintenance and key behaviors are high physical activity levels, a lower calorie diet, and self-weighing. Studies have incorporated these strategies; however, the most intensive phase occurs during weight loss initiation with the maintenance phase occurring after the novelty and intensity has faded. Increasing intensity duration improves weight loss, but there is a point of diminishing returns as people eventually stop attending sessions. Another key question is optimal intervention timing. One model suggests that maintenance is enhanced by teaching people about the key behaviors and helping them with these behaviors. This model suggests that maintenance programs should be designed like weight loss programs with scheduled sessions addressing relevant behaviors. The strongest maintenance approach may integrate these and other models, and include core behavioral messages followed by “just in time” intervention delivery in response to small weight gains. This research will evaluate the efficacy of an innovative approach to promoting weight maintenance among recent weight losers. This research is innovative because it targets individuals who have recently lost weight and evaluates a novel intervention to enhance weight maintenance. Results will provide important information on the effectiveness of a new weight loss maintenance intervention that could potentially be widely disseminated.

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Global Studies on the Prevention of Obesity

Investigator: Robert W. Jeffery
Funding Agency: UMN Faculty Research Circle Grants in International Studies, Interdisciplinary Center for the Study of global change & Office of the Vice President for Research
Obesity is a disorder of energy balance, i.e. excess body fat accumulates when energy intake (eating) chronically exceeds energy expenditure (physical activity). Thus, at one level the answer to why we are gaining weight is a simple one. We are eating more and/or are being less physically active than we were a few decades ago. The specific contributions of different behaviours to the obesity epidemic are, however, far from clear. Most scientists agree that changes in population rates of this magnitude and in this short a period of time are most likely due to changes in the environment, rather than in underlying biological processes. However, the potential environmental influences are numerous and available scientific understanding of them is extremely limited. Possible environmental influences include new products that may encourage over consumption, increased affordability of food products, increased availability and convenience of food, and changes in information people receive about obesity related behaviours. Also implicated in obesity are environmental design choices that have made people more dependent on motorized transportation, social policies that have deemphasized physical activity and vastly increased availability and variety of passive electronic entertainments. It is also possible that changes in social influences operating through normative values and beliefs and changing life styles may affect obesity. The project is specifically designed to build a collaborative research relationship among researchers at the University of Minnesota around the topic who have complementary skills. It is also designed to build collaborations and between University of Minnesota researchers and researchers in Melbourne, Australia, who also have complementary skills.

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Environmental Interventions to Prevent Weight Gain Prevention

Investigator: Jennifer A. Linde,   Simone French,  Lisa Harnack
Funding Agency: NIH/NIDDK
Obesity is a rapidly growing health problem in the US for which neither effective treatment nor preventive measures are currently available. It is now widely accepted that environmental factors that encourage eating and discourage physical activity are important contributors to the problem, and it has been suggested that environmental interventions may be needed to achieve reductions in population obesity. The study will assess the efficacy of a multicomponent environmental intervention in preventing weight gain among working adults with various interventions taking place at the workplace. It is hypothesized that employees in intervention worksites will decrease energy intake, increase energy expenditure, and reduce weight gain compared to those in comparison sites over two years. It is also anticipated that the effects of the intervention on behavior and weight will be related to degree of exposure to intervention activities.

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Maintenance-Tailored Obesity Treatment

Investigator: Robert W. Jeffery,   Andrew Flood
Funding Agency: NIH National Institute of Diabetes & Digestive & Kidney Diseases (NIDDK)
Recent dramatic increases in prevalence have made obesity the number one nutritional problem in the US. Of particular concern is the fact that, although available treatments are effective in producing clinically significant weight loss, their ability to sustain weight loss long term is poor. The project is based on a conceptual analysis of this problem that argues for greater attention to two issues related to the temporal dynamics of the challenge of long-term weight control. These are: 1) the environment is continually changing and is not supportive of weight control and 2) the intervention methods that are effective in inducing short-term changes in behaviors and weight often lose their potency over time because of habituation. . Obese men and women will be randomized to either standard behavior therapy (SBT) or to a maintenance-tailored treatment (MTT) for 18 months, followed by 12 months of no-treatment follow-up. It is hypothesized that weight losses in the MTT group will be better than those in the SBT group, show better compliance to behavioral assignments, express more enjoyment and awareness of the treatment process, and have higher efficacy expectations in regard to handling future challenges to weight control.

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Examining the Obesity Epidemic through Youth, Family, and Young Adults

Investigator: Robert W. Jeffery,  Leslie Lytle,  Eileen Harwood,  Simone French,  Mark Pereira,  Jean Forster
Funding Agency: NIH/NCI RFA CA-05-0102005-10: Transdisciplinary Research on Energetics and Cancer
The purpose of this center is to conduct transdisciplinary research, training, and outreach on obesity and cancer in youth, family, and young adults. The proposed Center will address questions about the etiology, prevention, and treatment of obesity in youth and families, and explore biological pathways that may link obesity to cancer.

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Study of Health Outcomes of Weight Loss (Look AHEAD)

Investigator:  Robert W. Jeffery ,  Richard S. Crow
Funding Agency: National Institute of Diabetes and Digestive and Kidney Diseases
This is a field center for the Study of Health Outcomes of Weight Loss, which is a multicenter, randomized, clinical trial designed to examine the effects of sustained weight loss on health outcomes in individuals with Type 2 diabetes. The trial has three study groups: 1) community care, 2) lifestyle intervention (comprised of an intensive and sustained program of counseling for diet and exercise behavior change), and 3) lifestyle intervention plus pharmacologic intervention (Orlistat and/or sibutramine). The primary study outcome is carotid intima-media wall thickness. Secondary outcomes include glycemic control, cardiovascular risk factors, cardiovascular and cerebral event rates, cardiovascular disease, and psychosocial well-being.

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“Ready, Set, ACTION!: A Theater-Based Obesity Prevention Program for Children

Investigator:  Dianne Neumark-Sztainer
Funding Agency: NIH/NIDDK
School-based interventions have great potential to reach children from ethnically diverse, low-income backgrounds who are at high risk for obesity. However, parents provide a major source of influence for their children, and empirical findings suggest that family level participation in school-based interventions is typically low. Results from formative work show that a good way to reach out to parents is by inviting them to a performance by their children. The primary aim of this study is to examine the feasibility of an innovative theater program, Ready. Set. ACTION!, that reaches out to children and parents. Intervention messages are based on the children’s own experiences and thus personally and culturally relevant to children and their parents. The after-school program is being run for a 12-week period and reaches out to parents through home food and fitness packs, home challenge activities, healthy eating opportunities, and a play performance. The intensive portion of the program is followed by booster sessions in which children further enhance their skills as agents of change. Results from this study will provide insight into how to engage parents in school-based interventions.

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Effects of Dietary Composition on Exercise Tolerance in Obese Adults

Investigator:   Mark A. Pereira
Funding Agency: American Heart Association
We believe people’s physiological responses to exercise have an important systematic influence on their psychological response to exercise, which we refer to as ‘exercise tolerance’. We theorize that the composition of the diet may affect exercise tolerance through its known impact on metabolic fuels (i.e. glucose and fatty acid. Specifically, typical high carbohydrate diets may have a deleterious impact on exercise tolerance through effects of postprandial hyperinsulinemia on the partitioning of metabolic fuels from oxidation to storage. Our research has shown that high carbohydrate diets, relative to energy-matched moderate carbohydrate diets, result in reactive hypoglycemia, an augmented drop in resting energy expenditure during weight loss, and greater perceived hunger. We theorize that the proposed interplay between the physiological and the psychological systems may have implications for the maintenance of a physically active lifestyle. To this end, we will use a randomized cross-over design to compare the effects of two dietary patterns – Control (high carbohydrate) v. Experimental (lower in carbohydrate, more slowly digested carbohydrates) — on obese individuals. A second version of the Experimental diet will be high in protein. Specifically, we will examine the relative effect of the diets on metabolic fuels during standardized exercise testing; perceived exertion, energy, and mood during standardized exercise testing; and free-living day-to-day reported energy levels, mood, and well-being. By addressing these aims, the proposed study will contribute to our understanding of the interplay between the physiological and psychological systems that regulate people’s exercise behavior. Moreover, if the composition of the diet is shown to have a causal influence on exercise physiology and, in turn, on how people think and feel about exercise, it will provide the basis for new directions in the design of interventions to promote physical activity and prevent obesity.

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“Effects of Breakfast on Hunger, Mood, and Cognition in Youth (A Pilot Study)

Investigator: Mark A. Pereira,  Leslie Lytle
Funding Agency: Minnesota Obesity Center
This study is designed to evaluate the effects of eating breakfast and to examine the content of breakfast meals on appetite, mood, and cognitive performance in boys. Many studies have documented high rates of skipping breakfast among youth, but prospective and experimental studies are lacking. We hypothesize that children will be less hungry, less irritable, more energetic, and demonstrate superior memory and analytical skills following a breakfast meal in comparison to skipping breakfast. Due to effects of dietary composition on blood glucose and satiety, we further hypothesize that children may be less hungry and perform better on these parameters following a balanced breakfast meal containing whole grain cereal, fruit, and milk than after a refined carbohydrate breakfast meal including a pastry and fruit juice. The proposed study will include a cross-over experimental design in 15 overweight adolescent boys in good health and between the ages of 11 and 14 (middle school). The study findings may provide insight into the role of breakfast habits in modulating energy regulation, behavior, and academic performance.

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Effects of Dietary Carbohydrate on Glycemia, Appetite, and Mood

Investigator: Mark Pereira
Funding Agency: Minnesota Medical Foundation & General Clinical Research Center, U of MN
This study is aimed at testing the effects of four different breakfast meals, and of a fasting (water only) condition, on postprandial blood concentrations of glucose, insulin, and fatty acids, and on appetite and mood levels. The meals vary in amount and type of carbohdyrate and fat. This pilot study will help us to design protocols needed to test other potential effects of dietary composition, such as effects on physiologic and psychologic states during and after exercise, and ultimately adherence to dietary and physical activity interventions.

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The Effects of Fast Food on Body Weight and Health Status

Investigator:  Mark Pereira,  Simone French
Funding Agency: Nutritional Resource Foundation
Fast food is a premier dietary pattern in the U.S., yet no clinical trial has been conducted to evaluate the effects of eating at fast food restaurants on body weight and related health parameters. This study is a randomized controlled crossover trial to compare the effects of eating fast food on body weight, body composition, and chronic disease risk factors in young overweight and obese adults. Twenty healthy overweight and obese adults will be recruited from the University and surrounding community. Participants will be assigned to receive two months of each treatment – 1) eating at fast food restaurants daily, or 2) eating home prepared meals with little or no restaurant use. Body weight, body composition, risk factors for chronic disease, detailed dietary intake assessment, and physical activity will be measured before during and after each intervention period. The findings will have the potential to contribute significant scientific information to the limited body of evidence regarding the potential impact of eating fast food on health.

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Strength Training for Obesity Prevention

Investigator: Robert Jeffery,  Lisa Harnack
Funding Agency: NIH
This randomized controlled trial will test the efficacy of twice weekly strength training for preventing age associated increases in body fat (total and visceral) in women aged 25-44 and BMI 25-35. Primary outcomes are total percent fat and visceral fat. Secondary outcomes include insulin sensitivity, bone density, blood pressure, blood lipids, and a variety of psychosocial correlates of physical activity.

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Primary prevention of diabetes: population-based methods to identify people most likely to benefit from interventions

Investigator:  Susan J. Duval,   David Jacobs,  James Pankow
Funding Agency: CDC
We will develop a non-invasive or minimally invasive screening tool to identify persons with impaired glucose metabolism. We will test the sensitivity and specificity of this tool in different subgroups, formed for example by sex, age, ethnicity and their combinations, and if needed modify the screening tool in the different subgroups. Our database includes sufficient ethnic variation and sample size to give precise estimates even for those subgroups which are not adequately represented in any individual study. Our large international database includes more than 40 studies and 500, 000 participants.