Tabla de contenido

two minute review

Are you currently burning carbs or fat? Lumen, a small breathalyzer equipped with Bluetooth to synchronize with an app for smartphones and Apple Watch, will tell you. It's still new to the world of fitness, but it's a tool that will work well for some users, while others will forget about it and leave it in a drawer.

Why do you need to know? Because Lumen tells us that our body's metabolism is very important, and it's true. Our metabolism is the mechanism that gives energy to cells and organisms and plays a vital role in weight loss. But while fitness trackers, smartwatches, heart rate monitors, and smart scales will tell you precisely what activities you've been doing and monitor your progress, whether it's improving your fitness or losing weight, they won't let you know. they will tell you how efficient your body is at burning calories, where and when to eat.

Lumen claims it helps you achieve "metabolic flexibility." It is effective when you start the morning burning mainly fat and then switch to carbohydrates depending on the intensity and duration of your activity. Indicate better overall energy levels, more effective weight loss, and the ability to see the effect on your body of exercising, running, swimming, or walking.

Is it backed by science? Lumen says his device has been validated as a metabolic measurement device by a study (opens in a new tab) conducted by San Francisco State University. And it's true, research from the San Francisco Department of Kinesiology has found that it “detects changes in metabolic fuel usage comparable to a standard lab metabolic cart, providing the ability to get real-time metabolic information for users on the go.” all circumstances."

In the "Acknowledgments" section of the study, it is revealed that the research was supported by Meta Flow Ltd., Lumen's parent company, but the study passed the peer review process.

A device no bigger than a pair of true wireless earphones in its battery case and inspired by the type of wearable devices that test breath alcohol levels, Lumen looks a bit like an e-cigarette/vaping device.

Light metabolism monitoring

(Image credit: Jamie Carter)

It's just as easy to use. You launch an app, follow the instructions to inhale, hold your breath for 10 seconds, exhale, and then wait for the results, which follow a few seconds later and tell you exactly what your metabolism is currently burning: mostly fat, mostly carbs, or in some point in between. It does this by monitoring the CO2 levels in your breath (high CO2 = carbs, low CO2 = fat).

Except he doesn't do anything that fast. During our long-term test, the breath test had to be repeated constantly, which meant that the measurements took much longer than expected. When asked to do this multiple times a day, he becomes quite domineering. Lumen is in need.

While it provides very specific nutritional information, actions and advice to the user, whether or not Lumen can become a practical health tracking tool depends primarily on user engagement. You'll either love Lumen or quickly forget it, but it's a truly new way to quantify your health, fitness, and nutrition.

Light Metabolism Tracker: price and availability

  • Prices start at € 199 / € 199 / AU € 275
  • It costs €19 / €19 / AU €26 per month thereafter

Originally launched in May 2020 to become the world's first wearable device to measure and track metabolism, Lumen is a high-end biotech device. It comes with a small travel case, charging station, and USB-C cable, and is sold at different prices depending on how long you plan to use it.

It has a three-month 'Metabolism Booster' deal for £199 / £199 / AU$275, an 'Advanced Fat Burn' deal for £249 / £249 / AU$345 and an 'Optimal Health' deal for £ 299 / €299 / AU€415, all of which include the device itself. They all auto-renew after this period for $19 / £19 / AU$26 per month.

So yes, Lumen is an expensive device, especially with the subscription attached, but you do get a 30-day trial period during which you can cancel everything and return it for a full refund.

Tracking Light Metabolism: Design

  • weighs 74g
  • soft touch material
  • The charging base uses USB-C

Design rating: 4/5

The breathalyzer, which contains a CO2 sensor and a flow meter, is a fancy piece of equipment that looks expensive. A soft-touch matte finish takes care of this, though the mouthpiece is metal, adding a premium feel as you inhale and exhale. On the front is a ring of LEDs that light up to indicate different modes: green for charging and purple for connected to your phone.

Light metabolism monitoring

(Image credit: Jamie Carter)

Although it's designed to sit on its USB-C cable-powered charging dock, the Lumen's battery lasts around 14 days, which means you can take it on the road without having to charge its charging dock as well. In our test, Lumen and the app always automatically connected to each other, and there were no dropouts, lags, or connectivity issues of any kind. It even detects if your heart rate is particularly high and asks you to sit down for a moment before taking a measurement.

However, it is a nifty product in more ways than one. After a few weeks there is a buildup of saliva and it tends to squirt out from the bottom when you blow on it. So aside from needing an occasional cleaning, it's best not to share your Lumen with anyone but very close family members - although you could technically share it with anyone else as long as you download the separate Lumen app to your smartphone and create your own profile.

Light metabolism monitoring

(Image credit: Jamie Carter)

Light Metabolism Tracking: Performance

  • Often requires two breath samples
  • quite demanding
  • It takes two weeks to get serious.

Performance rating: 3/5

Although it is advertised as a device that only takes 10 seconds to use, in practice it is a very time consuming device. We encourage you to use it about 30 minutes after waking up, before eating, after eating, before exercising, and late at night (the latter is especially hard to remember).

This routine is made more difficult to follow because Lumen requires two breath samples too often, effectively doubling the required commitment. The app also insists that the user wait 15 seconds between samples.

Light metabolism monitoring

(Image credit: Jamie Carter)

This is the real problem with Lumen; Instead of the honeymoon period you get with most new gadgets, this one gives you the opposite via a boring new daily grind and a lack of ideas in return. That's a problem because only after two weeks of continuous use do you get a weekly summary, a "Lumen Flex Score" (an indication of how flexible your metabolism is), and a personalized nutrition plan.

The more you use Lumen, the more it will do for you. If you give a pre-exercise sample, adapt the advice based on your results. So, after telling Lumen that we wanted to do a "pre-exercise" test and choosing from a list of activities and durations, it measured our metabolism and told us that we were primarily burning fat.

He then told us that we needed fuel for our training to give us the energy we needed (because burning fat doesn't give muscles the energy they need for a race). However, he then got very specific, recommending eating high-glycemic carbohydrates like fruit, dates, bread or cornflakes 15 to 60 minutes before the race.

Light metabolism monitoring

(Image credit: Jamie Carter)

When we got back, we measured again and were told we were now burning carbs; not surprising considering we had just eaten bread, but it is proof that Lumen is accurate and cannot be fooled. She then informed us that we needed to eat a small serving of low to medium glycemic carbs within 30 minutes to two hours: yogurt, milk, muesli, or any bran. His nutritional plan is also full of very specific advice, such as eating 45g of protein.

Lumen is a very serious professional device, although it can be disconcerting at first. Therefore, the company offers a one-on-one onboarding video call and sends out helpful follow-up emails that use helpful and supportive language. You just need to fully commit to it, and that will be a problem for many potential users.

Light Metabolism Tracker - Companion App

  • The Lumen app is free.
  • Easy to use and of good quality.
  • The first two weeks can be frustrating due to a lack of information.

The free Lumen app (opens in a new tab) is excellent, never once crashing during our extensive review. It is also amazing to hold the user's hand. We have to, because who among us knows how or why to use a breathalyzer?

The first thing it does is teach you how to inhale and exhale into the device. Then it gives a visual countdown for each step; exhale now until the circle on the screen turns green, hold your breath for 1, 2, 3… exhale now until the circle disappears. If you mess up the timing, you have to start the whole process over again. It's easy to learn, but it takes a few tries.

Light metabolism monitoring

(Image credit: Jamie Carter)

After exhaling into the device, the app shows you a pie chart of half a circle divided into five colors; blue on one end for primarily burning fat and orange on the other for primarily burning carbs.

For the first two weeks, that's it, and it's a frustrating time because you feel like you've wasted time discovering useless data. Only after you've been using Lumen for a few weeks (if you get to that point) do you begin to figure out what to eat, when to exercise, and how much sleep to get.

Light metabolism monitoring

(Image credit: Jamie Carter)

Lumen now also offers an Apple Watch app that pulls data from the breathalyzer, lets you log your carb intake, and set your daily "carb budget" if you think you need low-carb days (which you seem to be obsessed with).

First revision in September 2021

Light Metabolism Tracker: Buy it if?

Light Metabolism Tracker - Don't Buy If

Tracking of light metabolism: also consider

Lumens: price comparison

Show similar items (opens in a new tab)Amazonas (opens in a new tab)

Share This