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United States Department of Agriculture

Agricultural Research Service

Research Project: Dietary and Lifestyle Factors Affecting Food Intake and Energy Metabolism in Lean and Overweight Individuals

Location: Food Components and Health Laboratory

2012 Annual Report

1a.Objectives (from AD-416):
Objective 1: Determine the role of carbohydrates, including whole grain sources, protein, and fat and their interaction with physical activity on food intake and energy metabolism. Sub-Objective 1.A: Evaluate the influence of dietary macronutrient composition—specifically, on the role of complex carbohydrates (including whole grains) on metabolic flexibility, insulin sensitivity, and energy balance. Sub-Objective 1.B: Determine the extent to which the day-to-day variation in daily voluntary food intake is related to the variability in physical activity and changes in physiological and metabolic factors related to energy balance, satiety and hunger, and the extent to which these are modified by whole grain consumption. Sub-Objective 1.C: Identify behavioral and social influences on food intake and selection.

Objective 2: Develop mathematical models relating blood glucose kinetics to whole body substrate oxidation. Sub-Objective 2.A: Determine the effect of physical activity, gender and age on postprandial and 24-h substrate oxidation and glycemic control. Sub-Objective 2.B: Develop predictive models and algorithms for existing ambulatory physiological monitoring systems to estimate real-time blood glucose and substrate oxidation based on continuous estimates of energy expenditure and duration and intensity of physical activity.

1b.Approach (from AD-416):
Acute and long-term controlled human studies will evaluate the effects of various macronutrients, including consumption of whole grains, on metabolic flexibility and risk factors observed with excess weight. Overweight/obese (body mass index [BMI] >27) and control (normal weight, BMI <25) adult individuals will be chosen from the diverse population with special interest in groups identified to be at high risk for obesity. Intervention studies in which intake is either controlled or ad libitum will be undertaken, with samples collected periodically. Measurements would be made during weight loss and weight maintenance periods in overweight subjects. Measurements will be made for markers of glycemic control, energy regulation, and lipid metabolism, blood pressure, body composition, measures of satiety, and energy expenditure, as well as the effect of physical activity on metabolic flexibility. In an effort to better understand macronutrient metabolism, mathematical modeling techniques will be used to estimate substrate oxidation from glucose monitoring techniques. In addition, a study evaluating factors perceived as influencing adherence to current Dietary Guidelines will be continued.

3.Progress Report:
Two study protocols were approved by the Instituitional Review Board to investigate the role of whole grains (oats and barley) in modulating glucose tolerance and insulin sensitivity. One study is to investigate the acute effects of consuming whole grains over a short timeframe (7 hours) and the other study is to investigate their effects on glucose and insulin following chronic consumption (6 weeks) as part of a controlled diet.

Last Modified: 4/17/2014
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