Northwestern University researchers have developed a breakthrough algorithm that finally makes fitness trackers accurate for people with obesity, achieving over 95% accuracy in measuring calories burned during physical activities. This discovery addresses a critical gap that has left millions of users with discouraging and inaccurate health data for years.
The Problem with Current Fitness Trackers
People with obesity exhibit significant differences in walking gait, movement speed, and energy expenditure patterns compared to individuals of normal weight, yet fitness trackers have been designed using data primarily from non-obese populations. The inspiration for this research came when lead scientist Nabil Alshurafa attended an exercise class with his mother-in-law who has obesity. Despite working harder than anyone else in the class, her fitness tracker barely registered her effort on the leaderboard (ScienceDaily, June 20, 2025).
Breakthrough Research Methodology
The Northwestern team tested their algorithm against 11 state-of-the-art algorithms using both research-grade devices and metabolic carts that measure oxygen consumption and carbon dioxide production. Twenty-seven study participants with obesity wore fitness trackers while performing various physical activities, with their actual energy burn measured using the gold-standard metabolic cart method. The new algorithm demonstrated remarkable accuracy by accounting for the unique physiological differences in how people with obesity move and burn energy.
Real-World Impact and Applications
This advancement enables more accurate daily activity tracking for people with obesity, making it easier to monitor energy expenditure and tailor weight management interventions. The open-source, dominant-wrist algorithm can be integrated into existing commercial fitness trackers, potentially transforming the experience for millions of users who have been receiving inaccurate feedback about their physical activity. The technology bridges a critical gap in fitness monitoring that has historically left people with obesity feeling discouraged and excluded from accurate health tracking.
My Recommendations
If you have obesity and use a fitness tracker, be aware that current devices may significantly underestimate your energy expenditure. Look for updated devices that incorporate this new algorithm technology as it becomes available. In the meantime, focus on consistent daily movement rather than relying solely on calorie burn estimates from your device. The most important factor for health improvement is establishing regular physical activity habits, regardless of what your tracker displays. Consider consulting with a healthcare provider who understands the unique challenges of fitness tracking in obesity to develop an appropriate exercise plan.