Lumen Review – Tracking Metabolism

Everyday you give away mountains of data without any benefit. Each time you exhale, the makeup of your breath contains a mountain of information about how your body is working. Lumen, the metabolism tracking device, uses  carbon dioxide measurements in your breath, CO2, to gauge what your body is processing. This measurement can be used to define your metabolism and figure out how your body responds to your diet. 

lumen device and charging stand


Lumen Diet and Metabolism Monitoring

For athletes trying to carbo load before an event,  enthusiasts trying to stay in ketosis, intermittent fastest trying to burn fat, or anyone else, you can then change your diet. This Lumen metabolism tracking review can help figure out how you can hack your metabolism.

Recently Lumen has improved their tracking. You now only have to take one breath sample, in the past it was three. This brings the time down from a 2-3 minute reading to just 20-30 seconds. Each sample really only requires a single steady breath in, hold for 10-15 seconds, then breathing out. There’s nothing more to it.At first the pace of exhale and aggressiveness of inhale have to be learned, Lumens app helps figure this out. It took a handful of test breaths to get the app to register. 

The Lumen Level is broken down into a scale of five. They define the target as in the 1-2 range, which equates to mostly fat burning. It’s easy to get a 5, just have an extra dessert before climbing in bed. getting the Lumen score of one or two is a little bit harder. Intermittent fasting makes it easier, and the final meal of the night have the most impact. 

Once you know what your body is burning, fats or carbohydrates, you can change your diet. Lumen makes broad suggestions about the macro balance, or the ratio of fats to carbohydrates to protein. They provide information to help understand what foods are better for each. 

lumen nutrition plan summary

The Lumen app also makes sure to tell you why the macro ratio it provided is suggested.

Although the diet is helpful, it does not take into consideration any of your personal goals. If you don’t want a fat burning diet, maybe you are a distance runner or endurance athlete who prefers quick burning carbohydrates, there is no way to tell Lumen this. This Lumen review is more than just about metabolism tracked… Lumen tries to be a behavior modifier.

The diet recommendations then are not personalized, which is a shame. This seems to be the major drawback of a device and offering that is inherently so personal.

No two people will react the same to identical diets. Even so, if you are able to look past this the Lumen readings can still be used to gauge how your diet is effecting you.

So, Is Lumen A Gimic? Or is it Legit?

Beyond the daily morning score, you can also track what you did in prior days to look for trends. Lumen let’s you enter your calories and macros consumed, as well as pulling information from trackers for workouts. This is important since a heavy day of activity can force your body to burn its energy stores differently. 

Overall the device itself is shown to monitor in a reliable fashion, but it is not causal of any changes. To influence and make behavior changes, you need to do something or take some action. 

Lumen Product Design Review

The Lumen device is designed to do two things. First, measure the CO2 from your breath. Second, report that measurement back to a database for monitoring and recommendations. 

To achieve the reading the Lumen stick has an onboard sensor and processor that you breath into. The unit is hand held and doesn’t require any specific orientation when using it. I still don’t know which side is “up”.

Lumen comes with a charging base, this helps keep the design small since it doesn’t have a huge battery compartment and battery door. The charging base plugs into a microUSB and altogether the unit looks decent sitting on a counter. 
lumen metabolism tracker on a desk

Readings are supposed to be taken early in the morning before vigorous movement. This likely means a bedroom or bathroom will be the right placement for it, and it blends in while although the shiny black appearance may differ from the rest of the room decor. 

Lumen fits nicely in hand. The only button on it is the pairing button, which is also used to turn it on with a simple press. A light ring also appears on the device and although it is multi-colored, it’s not really a feedback mechanism. You can’t take a reading unless the unit is actively paired and the app is open. 

This design is a bit of a bummer. In practice it would be much easier to just take an inhale and exhale into the unit, following a simple on device prompt from the light or other feedback. It would likely increase how easily taking a reading could be integrated into a routine. Instead having to pull out multiple devices and wait for the prompt is a pain. 

If you are not trying for a low carbohydrate diet then the Lumen also falls short. It is possible to take reading a before and after a run, but this is an option for calibration not for analysis of how a workout went. It’s not possible to link this to heart rate of effort and tell what you were burning during the workout, it’s not a live reading. 

Lumen Flex Score

The app also provides a Lumen Flex score, which estimates how well you body adapts at moving between the 5 levels. Eat low carbohydrates one day, it tells you how quickly you shift to fat burning. 

There is a lot more that could go into the flex score. Depending on your activity for the day will drastically change what your body is burning. Go out for a super long moderate effort hike (powered by a handful of snacks) and compare it to a stress inducing day watching your favorite team struggle while eating game time snacks (similar to the hike) and your body may process things entirely differently.