Posts tagged: Energy Expenditure

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A person running on a treadmill in a lab setting, the exact environment where Stanford tested fitness trackers against clinical calorimeters

Calorie TrackingFitness TrackersWearable Accuracy

Why Your Wearable's Calorie Count Is Wrong by 27 to 93 Percent

A Stanford study tested seven fitness trackers against clinical instruments. Heart rate was accurate. Energy expenditure was off by 27 to 93 percent on every device. The calorie number on your screen is not a measurement. It is a guess.

James Hoffmann

May 30, 2026 15 min read