ILSI Energy Balance Study

There are four stages in the proposed project: 1) We will validate EE and ES (hereafter, Fitbit_EE and Fitbit_ES) from a consumer physical activity monitor (Fitbit Alta HR™) and body composition analyzer (Fitbit Aria™) with gold-standard measures of DLW for EE and DXA for ES during a 14-day baseline period; 2) We will estimate EI using the intake-balance method during the 14-day baseline period; 3) We will calibrate daily Fitbit_EE and Fitbit_ES from consumer devices using a Bayesian semi-parametric measurement error modeling approach to estimate energy balance; 4) We will reassess our validation and calibration models of consumer devices during a 14-day post-study assessment period to evaluate changes associated with growth and development with gold-standard measures of DLW for EE and DXA for ES.

Aims of the proposed study are to:

Specific Aim 1. Validate and calibrate consumer devices to estimate energy balance using gold-standard methods and a Bayesian semi-parametric approach. Hypothesis 1: We will be able to jointly model measurement error for both EE and ES to create a calibration model that reduces bias and improves accuracy of consumer devices of EE and ES.

Specific Aim 2. Estimate energy intake using the intake-balance technique using consumer monitors. Hypothesis 2:We will use calibrated EE and ES from consumer monitors to estimate EI using the intake-balance technique, with values being superior to self-reported EI.