Archive · 28 Sep 2026
At-Home Metabolism Tracking in India: How Lumen Measures Fuel Use
Your body can use carbohydrates or fat to make energy.
Different devices measure different parts of this process.
A fitness watch estimates activity and energy use, while a continuous glucose monitor measures changes in blood sugar.
Lumen is a small device that analyzes the carbon dioxide in your breath.
It estimates which fuel, carbohydrates or fat, your body is using more at that moment.
A morning test can show what happens after sleeping and fasting.
Other tests can show how food, exercise, or fasting changes fuel use.
The goal is not always to burn more fat, but to help the body switch between fuels when needed.
Lumen requires active breath tests and may be most useful for people who regularly use health data to change their routines.
At-home metabolism tracking can involve fitness wearables, continuous glucose monitors, laboratory testing, or breath analysis.
Lumen estimates whether the body is using more carbohydrates or fat by analyzing carbon dioxide in exhaled breath.
Unlike a continuous glucose monitor, Lumen measures fuel use rather than glucose levels.
Repeated readings can help users study responses to fasting, meals, exercise, stress, travel, and routine changes.
At the time described, delivery to Mumbai cost roughly ₹30,500 before possible import duties, with membership included for the first year.
- Who
- Lumen, a consumer metabolic breath-tracking device developed by Meta Flow Ltd., and people monitoring nutrition, exercise, fasting, or metabolism.
- What
- A method for estimating whether the body is using more carbohydrates or fat through standardized breath measurements.
- When
- At the time of writing; the article does not provide a calendar date.
- Where
- The device can be ordered for delivery to India, including Mumbai.
- Why
- To understand fuel use and potentially guide workout fueling, meal timing, fasting, nutrition, and recovery decisions.
- Primary measurement
- Carbon dioxide in exhaled breath, along with airflow and pressure.
- Fuel information
- An estimate of the relative use of carbohydrates versus fat.
- Testing pattern
- Usually measured in the morning, with additional readings possible during the day.
- Comparison with CGM
- A continuous glucose monitor measures glucose, while Lumen measures estimated fuel use.
- Research
- One validation study involved 33 healthy adults and compared Lumen changes with respiratory exchange ratio measurements.
- Estimated Mumbai order cost
- Approximately ₹28,700 for the device plus ₹1,800 shipping, or roughly ₹30,500 before possible duties and taxes.
- Membership and warranty
- The first 12 months of membership were included, followed by an annual cost of approximately ₹14,300; the device included a one-year limited warranty.