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Ph.D., Department of Nutritional Sciences
University of Wisconsin
Office: 430 West Health Sciences Dr.
University of California
Davis, CA 95616
Phone: (530) 752-4163
Fax: (530) 752-5271 |
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Page Summary:
Biography
Research Interests
Research Objectives
Research Accomplishments
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Biography
Nancy L. Keim, PhD, RD, is a Research Chemist at the Western Human Nutrition Research Center. She leads studies to evaluate the Dietary Guidelines for Americans as they relate to achieving a healthy body weight. Dr. Keim received her PhD in nutritional sciences at the University of Wisconsin, Madison in 1980. She joined the USDA-ARS-Western Human Nutrition Research Center as a Research Chemist in 1985 and has served as a Research Leader and a Lead Scientist. At the University of California-Davis, Dr. Keim is an Adjunct Professor in the Nutritional Biology Department, a member of the Graduate Group in Nutritional Biology, and serves as a member of the Institutional Review Board for Social and Behavioral Studies. She is an active member of the American Dietetic Association and has served on an expert panel to evaluate the use of indirect calorimetry in clinical practice. She is also a member of the American Society for Nutrition, the American College of Sports Medicine, and the Obesity Society.
Research Interests
My research emphasizes the study of behaviors related to food intake and physical activity and how these affect energy metabolism and appetite. Areas of investigation include evaluating the effects of controlled interventions of energy intake and/or exercise energy expenditure on body composition, metabolic rate, and the underlying endocrinology related to glucose disposal, fat combustion, and food intake regulation; discovering pathways of intermediary metabolism that can be modulated by cognitive-behavioral factors related to food intake; determining optimal sources and amounts of different types of dietary carbohydrates that contribute to satiety, healthy eating behaviors, and reduce risk of chronic disease; and evaluating the benefits of achieving an active lifestyle in terms of preventing obesity and related chronic diseases.
Research Objectives
· Determine how the amount and type of dietary carbohydrates affect the flux of metabolic fuels, satiety, and subsequent food intake.
· Assess the ability of individuals to adhere to the recommended level of physical activity for preventing adult weight gain in the current Dietary Guidelines.
· In overweight adult women, determine if successful adherence to the physical activity recommendation significantly impacts food intake, insulin sensitivity, and the effects of psychosocial stress.
· Contribute to understanding the safe, upper limits for the quantity of added sugar or sweeteners that can be consumed by normal, overweight and obese adults to prevent undesirable health effects such as insulin resistance, chronic inflammation, development of abdominal obesity, or disordered eating.
Research Accomplishments
· Found that whole body metabolism of women with high levels of dietary restraint is geared to use carbohydrate for energy and has a decreased capability to burn fat. This finding may be indicative of a metabolism that favors storage of fat and contributes to the ease of weight regain in women who chronically restrain food intake.
· Provided the first evidence in humans that leptin influences hunger during conditions of calorie restriction: discovered that during long-term, controlled consumption of an energy-restricted diet, women who reported feeling most hungry had the largest relative decrease in circulating leptin levels.
· Found that consumption of a meal based on whole grains reduced circulating insulin levels, increased the use of fat for energy production, and altered the distribution of apoprotein components of lipoproteins. These data suggest that circulating lipids might be cleared from the blood more effectively when the carbohydrate consumed is from whole-grain sources.
· Developed and tested an electronic activity log that can be used to document physical activities in free-living volunteers. Demonstrated that this device accurately estimates physical activity energy expenditure for groups of subjects engaged in intervention trials.
· In collaboration with UC-Davis scientist, Dr. Peter Havel, determined that consumption of large quantities of beverages sweetened with fructose resulted in alterations in hormones associated with hunger, including insulin, leptin, and ghrelin. Long-term consumption of these fructose-sweetened beverages also caused elevated circulating triglyceride concentrations, reduced ability to burn fat for energy, decreased resting metabolic rate, and evidence of insulin resistance.
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