Completed Obesity Epidemiology Studies

Hispanic Community Health Study/ Study of Latinos – Nutrition Reading Center
Investigator:  John H. Himes, Lisa Harnack
Funding Agency: NHLBI/NIH
HCHS/SOL was 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 were followed with chief outcomes related to obesity, cardiovascular disease, and diabetes. The University of Minnesota was the Nutrition Reading Center for the study, and developed and oversaw the protocols, training, and analysis of dietary intake and other nutrition-related data.

Genetics of Infant Growth and Later Obesity
Investigator
: Ellen Demerath
Funding Agency: NIH/NICHD
This project used 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.

Visceral adiposity: Genetic and environmental influences
Investigator
: Ellen Demerath
Funding Agency: NIH/NIDDK
This project aimed 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).

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 theorized 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 theorized 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 used a randomized crossover 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 was high in protein. Specifically, we examined 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 study contributed 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.

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 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 varied in amount and type of carbohydrate and fat. This study helped 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.

The Effects of Fast Food on Body Weight and Health Status
Investigators: 
 Mark Pereira, Simone French
Funding Agency: Nutritional Resource Foundation
This study was 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 were recruited from the University and surrounding community. Participants were 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 were measured before during and after each intervention period. The findings have the potential to contribute significant scientific information to the limited body of evidence regarding the potential impact of eating fast food on health.