Location: Healthy Body Weight Research
Project Number: 3062-51000-057-00-D
Project Type: In-House Appropriated
Start Date: Oct 1, 2019
End Date: Sep 30, 2024
Objective 1: Determine the efficacy of a DGA-style diet combined with DGA-recommended exercise, as well as individual differences on alterations of physiological and psychological factors associated with successful weight loss and maintenance. Sub-objective 1A: Determine whether consumption of the DGA weight loss diet will produce a greater reduction in CLGI than weight loss when reducing calories with the Western diet. Sub-objective 1B: Determine whether consumption of the eucaloric DGA diet will produce a greater reduction in CLGI than the eucaloric Western diet. Sub-objective 1C: Determine whether executive function training will reduce impulsive responses to, valuation of, and attention for energy-dense foods. Sub-objective 1D: Determine whether executive function training will result in greater weight loss maintenance over 6 months than usual follow-up care. Objective 2: Test individual differences in the efficacy of dietary intake patterns and exercise to promote healthy metabolic and ingestive behavioral responses. Sub-objective 2A: Determine the independent and synergetic effects of diet and PAGA-recommended amounts of physical activity on metabolic flexibility. Sub-objective 2B: Determine the association between dopamine (DA) release as measured by electroretinography (ERG) and food reinforcement. Objective 3: Determine the relationships among exercise, dietary intake, inflammation, fitness, and behavior motivation. Objective 4: Determine the role of fat mass, fat-free mass, resting metabolism (RMR), and cellular signals on behavior motivation and appetite control.
The Dietary Guidelines for Americans (DGA), which include the Physical Activity Guidelines for Americans (PAGA), is the primary U.S. government resource for weight control. We propose that chronic, low-grade inflammation (CLGI) limits weight control by acting upon physiological and behavioral factors that moderate weight control. Diet and exercise reduce CLGI and provide weight control, but no one has investigated the efficacy of the DGA and PAGA to reduce CLGI, whether reduced CLGI promotes greater weight control, and the moderating roles of physiological and behavioral factors on the association of reduced CLGI with weight control. This study will test DGA- and PAGA-induced changes in CLGI and weight control. We will also determine the relation of change in CLGI with changes in novel putative physiological (metabolic rate, cell signaling molecules) and behavioral (food and exercise reinforcement, executive function) factors on the association of reduced CLGI that moderate weight control efficacy. To accomplish this, we will conduct a 9-month trial in 224 obese adults; a 3-month controlled feeding trial with four dietary treatment arms; 1) DGA with weight loss, 2) Western diet with weight loss, 3) DGA diet weight maintenance, 4) Western diet weight maintenance. Each dietary arm will have PAGA-recommended exercise and non-exercise arms. Post-trial is a 6-month weight maintenance period with participants randomized into executive function training intervention or control. The results will inform the DGA and PAGA; thereby helping clinicians, public health workers, and policymakers to improve the health of Americans.