My research interests revolve around understanding the relationships between the foods we eat, metabolic health, and body weight. Current areas of investigation include evaluating the benefits of consuming important foods such as whole grains or dairy products on energy expenditure, substrate oxidation, satiety and chronic disease risk factors; 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 benefits of an active lifestyle in terms of preventing obesity and related chronic diseases.
My research objectives are:
· Determine how the amount and type of dietary carbohydrates affect metabolic health and 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.
· Determine how eating breakfast contributes to a healthy body weight.
· Contribute to determination of the safe, upper limits for consumption of sugars or sweeteners by normal weight, overweight and obese adults to prevent undesirable health effects such as weight gain, development of abdominal obesity, or disorders of lipid metabolism or ingestive behavior.
· Found that whole body metabolism of women with high levels of dietary restraint is geared to use carbohydrate for energy and has a reduced capacity to burn fat. This 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: during a long-term energy restriction, 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, suggesting that circulating lipids might be cleared from the blood more effectively with whole-grain carbohydrates.
· Developed and tested an electronic activity log that can be used to document physical activities in free-living volunteers.
· 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.