Location: Obesity and Metabolism Research
Project Number: 2032-51530-025-01-T
Project Type: Trust Fund Cooperative Agreement
Start Date: May 1, 2016
End Date: Apr 30, 2020
Objective 1: Identify regular dairy consumers and non-consumers using standard diet assessment methods; establish correlations between self-reported perceptions of hunger and satiety and associated endocrinology across the entire sample and within dairy consumer and non-consumer groups. Objective 2: Develop and compare models of satiety for consumers and non-consumers based on multivariate statistical analyses.
This project is a sub-objective of the larger “WHNRC phenotyping project” which is a cross-sectional study designed to assess participants’ physical and behavioral characteristics coupled with a standardized postprandial meal challenge test to gauge metabolic flexibility. For the main study approximately 400 adults (18-65 years) will be recruited over the course of four years, with equal representation of gender and BMI representing normal to moderately obese. Demographics, physical measurements, biological specimens, diet and health assessments are done to fully characterize each individual’s dietary, biological, environmental, and behavioral phenotype. Using results from a food frequency questionnaire, dairy consumers will be defined as those who report using, on average, at least two servings of milk, yogurt, and/or cheese per day and whose 24-hour dietary recalls confirm the use of dairy products. Non-consumers will be defined as those who report no use of dairy products on both the food frequency questionnaire and the 24-hour diet recalls. We anticipate based on our experience in previous studies that out of the 400 volunteers studied, at least 10% will be classified as dairy consumers (n=40) and 10% as non-consumers (n=40). In selecting the final samples of consumers and non-consumers, we will match gender, age, and BMI of the groups as closely as possible prior to evaluating and comparing the satiety models. The following measurements are currently planned and will be used to develop the satiety models: • Body composition: body fat mass and fat-free mass. • Resting metabolic rate, postprandial metabolic rate, and physical activity energy expenditure. • Associated measures representing tonic appetite signals arising from fat mass (leptin), and the active metabolic mass (resting metabolic rate). • Estimation of adequacy of self-reported energy intake. • In response to a high-fat challenge meal, episodic signals including glucose, insulin, the orexigenic hormone (ghrelin) and anorexigenic hormones (GLP-1, GIP, PYY3-36, and CCK). • Measurement of endocannabinoids by LC-MS as a measure of non-homeostatic, hedonic drive to eat. • Self-report (using visual analog scales) of meal satisfaction, hunger, and satiety in response to the challenge meal. • Eating behavior traits such as dietary restraint, disinhibition, and hunger. • Psycho-social stress levels and allostatic load. • Food preference evaluation with focus on sweet, savory, high and low fat foods. • Taste thresholds for sweetness, bitterness, and saltiness. • Cognitive tests of executive function. • Gut fermentation products in the circulation and feces, along with the microbiota characterization.