SHANON CASPERSON, PhD
Dr. Casperson received the B.S. degree in Exercise and Human Performance from the University of Houston, and the Ph.D. in Cell Biology from the University of Texas Medical School, where she studied how nutrition, specifically amino acids, and exercise independently and synergistically contribute to the maintenance of skeletal muscle mass. She joined the staff at the Grand Forks Human Nutrition Research Center as a postdoctoral research fellow in nutrition and obesity. In November 2014, she became a Research Biologist in the Center's Healthy Body Weight Research Unit.
My research aims to optimize nutritional strategies that promote attaining a healthy body weight and maintaining weight control. My research focuses primarily on the relationship between meal macronutrient composition (fat, carbohydrate, protein), dietary intake patterns, and energy metabolism. Small changes in meal composition and timing can make a big difference in how the body uses the foods we eat for energy. Utilizing whole-room calorimetry, we can precisely measure changes in energy metabolism in response to different foods, meal composition and meal timing. My research also examines how the foods comprised in meals and/or snacks may disrupt homeostatic regulation of food intake. Utilizing cutting edge technologies, we can understand the impact of the different foods and food components we eat on eating behavior.
- Established the negative impact consuming a sugar-sweetened beverage has on energy metabolism. Consuming a sugar-sweetened beverage with a meal decreases fat utilization and diet-induced thermogenesis. Moreover, when paired with a protein-rich meal, fat utilization and diet-induced thermogenesis are further decreased by at least 40%.
- Demonstrated the impact of beverage choice during a meal has on snacking decisions. Using an operant choice paradigm, we showed that consuming a non-nutritive sweetened (diet) drink with lunch increases the wanting of a sugary snack food 4 hours later.
- Demonstrated that changing the macronutrient composition of the meal influences snacking decisions differently in women and men. Using an operant choice paradigm, we found that consuming of a high-protein meal decreases the wanting of savory (i.e., chips) snack foods in women but not men. There was no difference between the women and men in the wanting of sugary snack foods.
- Established that daily protein intake patterns affects skeletal muscle protein synthesis. Evenly distributing dietary protein across meals (30g for breakfast, 30g for lunch and 30g for dinner) stimulates the skeletal muscle synthetic response to a greater extent than a more typical intake pattern of consuming most of the protein at the evening meal.
- Established that increasing the leucine content of each meal enhances the anabolic stimulus of a mixed nutrient meal in older adults.
- Demonstrated that during endurance exercise: 1) amino acid exchange increases, stimulating muscle protein synthesis without an age-related resistance to the anabolic effects of exogenous amino acids, however, following an acute bout of endurance exercise the anabolic effect of exogenous amino acids is reduced in aged muscle, although this does not manifest as noticeable changes in overall net protein balance, and 2) the molecular events underlying these changes are marked by increases in the activation of proteins involved in muscle hypertrophy signaling, and decreases in muscle atrophy signaling.