Properly calibrated smartphones and smartwatches can yield multicompartment body composition estimates that closely match laboratory standards and support precise, low-cost monitoring in remote and resource-limited settings.
Smartphone-based three-dimensional optical imaging showed strong agreement with laboratory air displacement plethysmography for body volume measurement.
Smartwatch-based bioelectrical impedance analysis showed strong agreement with a clinical-grade bioimpedance system for total body water estimation.
After calibration, the consumer-accessible five-compartment model estimates of fat-free mass and fat mass closely matched laboratory-derived five-compartment model estimates.
The study developed a five-compartment body composition model using only consumer-accessible devices by combining smartphone-derived body volume and smartwatch-derived total body water.
Both smartphone and smartwatch measurements required offset corrections to remove systematic biases before achieving agreement with laboratory reference methods.
This research suggests that everyday consumer devices — specifically smartphones and smartwatches — can be used together to measure body composition (how much of your body is fat versus lean tissue) with accuracy comparable to expensive laboratory equipment. The researchers had 30 adults undergo body composition testing using both high-end clinical tools and consumer devices. The smartphone was used to create a 3D scan of the body to estimate body volume, while the smartwatch measured the body's water content using a mild electrical signal. These two measurements were then combined in a mathematical framework to estimate fat mass and fat-free mass. The consumer devices performed well but needed mathematical corrections to remove systematic errors before their measurements matched the laboratory gold standards. Once calibrated, the smartphone body volume measurement matched laboratory results with an r² of 0.97, and the smartwatch water measurement matched with an r² of 0.98. The final body composition estimates from the combined consumer-device model agreed with the laboratory five-compartment model with an r² above 0.96 and an average error of about 2.1 kilograms. This research suggests that with proper calibration, affordable and widely available consumer technology could allow people to monitor their body composition outside of clinical settings — at home, in remote areas, or in resource-limited environments. This could be particularly meaningful for tracking muscle loss in aging populations, people with chronic illness, or those in areas without access to specialized medical equipment. The need for initial calibration against laboratory equipment remains a practical consideration for broader deployment.
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Upload Your LabsBennett J, Wong M, Liu Y, Kelly N, Quon B, Shepherd J. (2026). Consumer Technologies for Personalized Health: Feasibility of Five-Compartment Body Composition Self-Assessment Using Mobile Devices.. Obesity (Silver Spring, Md.). https://doi.org/10.1002/oby.70200