Lumen - let the conversation begin 😋

(Michael - When reality fails to meet expectations, the problem is not reality.) #148

Just tested about 1/2 an hour after finishing my main daily meal. BrAce 10.9. At 3:30pm Lumen 3, tested on the balcony; at 3:40pm Lumen 2, tested in my computer room.

(Ethan) #149

Unfortunately, I found the pattern easily. I blow a 4 within 12 hours after weight lifting. I blow a 3 always otherwise. Perhaps if I fast a few days, I’ll blow a 2. That isn’t really of any use to me. The raw numbers would give me better information maybe.

(Ethan) #150

Blew a 2 this morning. Waited 5 minutes and then blew a 4

(Michael - When reality fails to meet expectations, the problem is not reality.) #151

(Michael - When reality fails to meet expectations, the problem is not reality.) #152

Two Lumen 1s in a row.

I started a fast yesterday at approx 11am. Blew a couple 2s and 3s on the Lumen during the rest of the day. BrAce was between 9 - 16 for all samples. Blew a couple of 3s this morning at 5 and 9am. BrAce was 10.5 ppm and 10.3 ppm respectively, surprising stable for 4 hours! At 9:30 I broke the fast (so about 20 hours or so) with my daily keto coffee. Blew two 1s in a row afterwards: at 1 and 2:45 pm. Again BrAce was remarkably close at 12.4 ppm and 12.5 ppm.

I just finished my main meal of the day and will test again in a couple hours.

(Michael - When reality fails to meet expectations, the problem is not reality.) #153

Check out this:

(Michael - When reality fails to meet expectations, the problem is not reality.) #154

Well, after measuring glucose for nearly two weeks now - the sensor self-destructs in 2 days! - I am coming around to the possibility that the Lumen is actually working as designed. Despite my 3+ years in ketosis, my glucose is consistently withing the mid-low ‘normal’ range. That glucose is not disappearing by magic and it’s not getting stored as fat. Therefore, it must be getting burned - presumably by the various cells/organs that can not burn ketones and/or fatty acids. I think the Lumen is detecting it.

My hypothesis that my Lumen ‘range’ is likely something like .71 - .76 RER is starting to make sense, if in fact the Lumen is detecting that minimal glucose burn and reporting it as ‘carbs’. Yes, it would be immensely more useful if the Lumen indicated actual RER rather than an arbitrary range of only 5 possible values. Still, instead of comparing it to BrAce, I intend to compare it to glucose the next time I buy a sensor. I think that will be interesting, indeed. Stay tuned.

Starting out help
(Karim Wassef) #155

just catching up here.Is there any way to use the Lumen to calculate RMR?

(Michael - When reality fails to meet expectations, the problem is not reality.) #156

At the moment, no.

(Jonathon Bullock) #157

Hi Everyone,

I’ve just signed up to this forum after coming across this post. I haven’t even had chance to explore the rest of the site yet but I felt I needed to reply because I might be of some assistance. A little background regarding me, I started my Keto journey a couple of years back and did really well, was super happy with results and the benefits the lifestyle brings, I fell off the wagon a fair bit for about a year but now I’m back to it and have been for 3-4 months (I’m by no means an expert and I’ve learnt so much reading just this one post). I’m a tech guy and just like @amwassil I’ve been on the hunt for some piece of technology that could help me monitor my progress doing Keto, I came across Lumen late last year and I placed an order straight away in the hope it would do what I wanted and if not it would be a new piece of tech to play with.

My Lumen arrived on Friday and after going through the initial setup and the suggestion to carb up for calibration day, I soon realised this might not work how I wanted it to. This is how I came across this post, I started google to see if anyone had managed to work the Lumen in a Keto positive way.

I think @amwassil is right, it would appear that the calibration day is setting the high and low values for you personally and the 1-5 score are just divisions between the two. This might be something that is useful for Keto but I think it leaves it open to way too much interpretation. I agree that raw values would be much more useful. This is where I might be able to help.

I’m a software developer here in the UK and I mainly deal with iOS apps and technologies, so the moment I figured out the 1-5 scale isn’t going to be that great I started work on picking apart how the Lumen works. I’ve only spent a few hours today on it but this is what I’ve achieved so far. I have written my own iOS app and I can successfully connect to the Lumen. I can see it has 2 bluetooth characteristics, one appears to have no use (or I am yet to discover it) the 2nd allows me to read and write, I have figure that sending 2 particular commands makes the device respond. One command gives me a static set of data (I’m initially expecting this to be something reporting the device battery level) the 2nd command starts the device streaming live data which changes and responds when I blow in to the device.

I’m some way off being able to figure out if there is a RMR number in the data somewhere, at this stage I’m looking at raw bytes and it’s fairly meaningless until I can start to spot some trends.

I will continue to play around with this but I wanted to know if people might find this useful and maybe anyone with more knowledge of the type of data this device is likely to report might be able to add some insight of what to look for.

I think my blood ketone meter is lying to me/broken/possessed
(Michael - When reality fails to meet expectations, the problem is not reality.) #158

@Jon2020 Welcome aboard the forums, Jonathan! Please keep at it and keep the rest of us informed of your progress. I have an iOS device (iPod Touch) that I use with my Lumen. I for one would definitely like to get real numbers out of the device if it’s possible to do so. I suspect it is, but…

@Karim_Wassef FYI

(Karim Wassef) #159

I agree. This has some great potential. The most direct is by using a real calibration for the device using real RMR data.

For example, I fast for 3 days and go get a real test for RMR at my local DEXA site. I capture the raw measured device results immediately before and after.

The. I eat my 5000 calorie keto bulk meals for 3 days with intense lifting and repeat the test.

Based on my past experience, those two behaviors will land me at 1500 and 4000 which are real min and max. If I can tie the device raw results to these real measurements, then the software can accept my data inputs for calibration and actually be usable.

This calibration might need to be repeated every three months for confidence or we could take more data points during the period (since the model may not be linear) but the ability to capture instantaneous RMR would be real.

My experience is that metabolism fluctuates wildly with many parameters- diet, activity, sleep, stress, temperature … and this would be the tool to help align the massive daily variation to real life control variables.

I could finally determine how my sauna and my ice baths are really impacting my metabolism!

Also - fellow engineer and scientist here. Let me know if you need some help or a guinea pig!

(PJ) #160

You might consider contacting the company. I think their likelihood of getting more sales, and having much more use of their product by people who are keto, lowcarb, or even diabetic but more interested in real data not ‘interpreted’ data, could be great if there was a decent app that successfully did what you are doing. Maybe you can get them to help you with info, or even funding who knows? If you present it well. I’d find the marketing manager of the corp and see if you can contact them directly.


I think someone should void their warranty, open the thing up, and start taking pictures. Let’s see if we can find a debugging port on the darn thing and get a firmware dump. Then we can reverse engineer the heck out of it, and maybe make the darn thing useful.

(Bunny) #162

Correction: …Lipogenesis (lipid droplet storage) rather than lipolysis (extraction of lipid droplet storage)…

Typing too fast…lol

(Michael - When reality fails to meet expectations, the problem is not reality.) #163

For what it’s worth, I fired off this today:

Case summary

Subject: RER


I eat keto. I purchased Lumen in the hope that it would assist me to determine relative percentages of fat/ketone and glucose burn during various daily activities and in response to eating various foods. I find the scale of 5 arbitrary categories useless for me. I encourage you to make raw RER numbers accessible to the user. Is there any possibility of you’re doing this? Thank you.

Sincerely, Michael Wassil

Your case was created.

We’ll get back to you soon.

(Carolyn aka stokies) #164

have you heard back?

(Michael - When reality fails to meet expectations, the problem is not reality.) #165

No - at least about RER. I did receive a response a couple days later asking me to complete a questionaire about my ‘support experience’. I did. :-1:

I have not given up, though. I’m going to keep pestering them about this.

(Michael - When reality fails to meet expectations, the problem is not reality.) #166


Date: Wed, 18 Nov 2020 10:51:14 AM PST
“Steven from Lumen” Add to Address Book Block Sender Allow Sender
Subject: Re: Re: Lumen + Garmin Integration Is Here!

Hi Michael,

Thanks for reaching out and for the great suggestion!

Currently Lumen measures the CO2 concentration in order to determine what your body is using for fuel.

In the future, we may add further sensors to a new version of Lumen where we can also determine O2 levels and be able to calculate and display RER values for customers :slight_smile:

If you have any further questions or suggestions, please let me know and i’ll be happy to help.

Best regards,

Date: Wed, 18 Nov 2020 11:40:19 AM PST
“MICHAEL WASSIL” Add to Address Book Block Sender Allow Sender
To: Steven from Lumen
Subject: Lumen + RER

Thank you for the prompt response, Steve!

There are lots of folks in the KETO community who would be very interested in
a device that measures RER. We currently have nothing that gives us direct
useful data re ‘fat adaptation’. We are left guessing based on ketone and
glucose measures, and dietary choices. It would be soooo useful to have a
direct measure that doesn’t require a trip to a sports nutrition center.

(Ethan) #167

Yeah. They are focusing on selling and not improving. I troll them on Facebook.