Fitbits and Other Devices Measure Energy Expended Well, But Less Reliable for Tracking Energy Storage and Intake in Research

Washington D.C. – Accurate measures of individual energy intake, storage and expenditure are important when assessing energy balance and its connections to food, nutrition and health. Unfortunately, current measures of these energy components are challenging, often laborious, resource intensive and marked by wide variability. A new study finds that commercial wearable devices like Fitbits provide robust estimates of energy expenditure compared to “gold-standard” methods, but results were mixed when used for energy storage and intake.

The findings were part of an article recently published in The Journal of Nutrition entitled “Commercial Devices Provide Estimates of Energy Balance with Varying Degrees of Validity in Free-Living Adults.” The research conducted in “free-living” healthy adults tracked their at-home daily activities which are more representative of daily behaviors.  

The study finds “that commercial devices have differential reliability and validity for capturing the 3 components of the energy balance model. Energy Expenditure estimates were the most robust overall, where Energy Storage were generally poor.”  The research calls for further study to understand measurement error, and calibration of wearable devices as they offer an opportunity to measure population-level energy intake, storage and expenditure patterns.

According to lead author Robin Shook, “These findings are a good representation of both the promise and concern using consumer devices. The consumer devices were quite good in terms of free-living energy expenditure estimations but lacking for energy storage. Importantly, future work should focus on better understanding the measurement error of these consumer devices and using statistical techniques to account for this error.”

The study was supported in part by The Institute for the Advancement of Food and Nutrition Sciences (IAFNS) which is committed to leading positive change across the food and beverage ecosystem. IAFNS is a 501(c)(3) science-focused nonprofit uniquely positioned to mobilize government, industry and academia to drive, fund and lead actionable research. iafns.org