Lumen is a pocket-sized device that measures your metabolism to help you achieve health and fitness goals; it’s just received a new update and now offers more precise results to show you the exact breakdown between the fat and carbs your body is burning. Added to that, it provides new meal suggestions that align with your personalized nutrition plan and the whole ecosystem fits nicely within the standards set by Apple Health.

One of Lumen’s key insights comes from its ability to analyze your breath at different times of the day to see how your daily activities impact the fat and carbs that your body is burning. This helps you understand how you process different macro food groups and how you react to exercise. The insights feed back into the recommendation given in your custom nutrition plan which determines what you eat before a workout and how metabolically flexible you are at switching to fat-burning when needed (almost all athletes and dieters need to be good at that).

Previously, Lumen used a simple 1-to-5 whole number scale where 5 represented carb burning and 1 represented fat burning. The same broad scale is kept but now Lumen gives you more granular readings – 1.8, for example.

Secondly, new meal suggestions are added that include combo meals. A combo meal can be more easily logged in the app and even provide a breakdown of the optimal timing for consuming carbs.

I looked in detail at Lumen soon after it was launched in 2019 and revisited it in 2022 after one of many updates that better allow it to work with Apple Watch and Garmin watches. Both my partner and I have found it useful to understand our workouts and our ability to burn fat and carbs. If you are really keen to understand more, then Lumen can be used in conjunction with a blood glucose sensor like Supersapiens which provides further, but different feedback albeit perhaps a little complex. Lumen is definitely easier to get to grips with!