Lumen​ is a handheld, portable device and app that measures your metabolism in real-time with just your breath.

It gives an insight into how efficiently users’ bodies are optimising fats and carbs to allow greater control over their health and wellness.

It works​ by measuring your carbon dioxide concentration by breathing into a handheld Lumen device.

These levels, calculated through Lumen, indicate the type of fuel your body is using to produce energy – a mix of fat or carbs.

It then provides you with personalised suggestions on when and what to eat to fuel your workout, based on your metabolism.

With Lumen’s daily insights, users can improve their metabolism by improving metabolic flexibility: the body’s ability to shift efficiently between using fats or carbs as a source of energy.

Michal and Merav Mor (pictured), twin sisters with PhDs in Physiology, co-founded Lumen and act as head of science for product and head of research and science respectively.

The sisters conceived of the idea for a personal metabolic tracker as they trained for an Ironman race.

Determined to improve their fitness and race times, the scientists sought out a way to track and test their metabolism to achieve peak fitness.

Michal More says: “While metabolism is key to weight loss, the only way to test metabolism was through a restrictive, hours-long laboratory process, leaving regular people with zero visibility into their metabolic rate and only haphazard ways of improving it.

“With Lumen, we are bringing scientifically rigorous insight into personal metabolism for the very first time, allowing anyone at home to measure how efficient their body is at burning calories, but also sharingresearch-driven recommendations on how they can reach their health and fitness goals faster.”

Lumen can provide numerous insights about the metabolism of an individual, as well as valuable scientific data to increase knowledge of metabolic flexibility and nutrition.

In a ​study​ conducted by San Francisco State University, Lumen has been validated to meet the gold standard for metabolic measurement.

The Lumen device is available at Lumen.me, currently priced at £299.

The device comes equipped ​with a travel case, charging dock, USB-C Cable, and Premium Customer Support.

Users can download the app for free ​on the Apple App Store and on Google Play.