Start Date: Jul 01, 2010
End Date: Sep 30, 2014
We will employ novel field methods and laboratory methods (assessment of energy expenditure by the metabolism of doubly-labeled water, energy substrate assessment by breath carbon isotope ratio, and body composition analysis by DXA) for objective assessment of total energy expenditure, physical activity energy expenditure, and energy intake in free-living individuals. We will link these data to environmental factors (such as season and weather), and to socio-demographic, biological, and psychosocial predictors of energy balance. This study will provide the basis for family-based interventions addressing the identified needs of targeted individuals for maintenance of healthy body weight. The primary outcome measure will be change in weight over time. We propose to build a robust model that can be used to inform family based interventions by including groups of potentially modifying covariates such as age, gender, race/ethnic group, SES, mood, weather, active transport patterns, chronotype, and location. The significance of seasonality will be tested, along with interactions by internal and external factors. Because of the complexity involved in combining data from multiple sources, state-of-the-science tools are needed for data processing, visualization, and analysis. We propose to cooperate with UCSD-EPARC who will provide remote training and support to the GFHNRC team throughout the study period and provide PALMS (Physical Activity Location Measurement System) software.