Lumen - let the conversation begin šŸ˜‹


(Michael - When reality fails to meet expectations, the problem is not reality.) #93

I agree it would be interesting. If someone wants to go for it, great! But if Lumen is actually measuring the ratio of O2 in and CO2 out, I donā€™t think it would make much if any difference. This device was apparently not designed with ketosis in mind, but rather for folks eating SAD or lower/low carb versions of SAD. In other words, there is always ā€˜supposedā€™ to be a mix of fat/carb burn. In ketosis weā€™re removing the carb portion. Maybe thatā€™s causing the AI engine to get confused and inflate the value of whatever CO2 itā€™s detecting. Just a guess.


(Ethan) #94

Even in ketosis, there is some glucose metabolism from gluconeogenesis


(Windmill Tilter) #95

No it does not make sense, nor is it plausible. $50,000 metabolic carts donā€™t seem to have that problem measuring RER. See the study on RER in ketogenic diets linked about 20 posts up.

The only issue I can recall with RER measurements in a metabolic ward was in a fasting study. After like 8 days of water fasting, the subjects started exhibiting RERā€™s of 69 or something like that, which is not theoretically possible. It was something to do with some strange feature of ketone metabolism in super deep ketosis. If I recall they did the chem math on paper, and made the adjustment in a second column as ā€œadjusted RARā€. But Iā€™m reasonably sure that deep ketosis caused underestimation, which was how they spotted it. Iā€™ll try to dig it up.

Assuming each of the six ā€œzonesā€ of the Lumen, are increments of 5 between 70 and 100, you shouldnā€™t be above ā€œ1ā€ on that meter, but there is no possible way you should be above ā€œ2ā€, unless youā€™re eating your bodyweight in protein daily.

This does assumes that the 1-6 scale corresponds to an RER value in some way. Does it?


(Michael - When reality fails to meet expectations, the problem is not reality.) #96

@Don_Q I donā€™t think Lumen is comparable to your $50K metabolic cart. It may or may not actually be measuring and calculating RER directly and/or accurately. Iā€™m trying to establish, using BrAce as a marker whether or not the Lumen is internally consistent with the values of BrAce. This to test my hypothesis and to see if we can actually get any useful results from this device. My initial assumption is that BrAce is somewhat consistent with level of activity. That may or may not be true.

I guess Lumenā€™s 1-5 numbers corresponds to RER thus: 1=< .76 ā€¦ 5=>.94 (the range .7-1.0/5).

As I mentioned above all the studies Iā€™ve seen so far were done on exercized subjects, not at rest. That could make a difference, or not. From the Abstract of the study you link above:

The main objective of this research was to determine the effects of a long-term ketogenic diet, rich in polyunsaturated fatty acids, on aerobic performance and exercise metabolism in off-road cyclists.

Also, I want to mention some possible confounders. I have been sick pretty much continuously for about 2 months with cold/flu combo. I had been (but not as since 4pm yesterday) medicating myself heavily with both Dayquil and Nyquil to control coughing. I suspect the illness has been and is affecting my ketone levels, including BrAce, which is currently quite a bit lower than when I was testing several times daily last spring/summer. 20-40 ppm then, 5-10 ppm now. Also, it may still take more time for whatever is in that cough syrup to get fully metabolized out of me. For example, I just took a 2 hour nap, tested immediately afterwards: BrAce 9.4 and Lumen 2. That doesnā€™t support my hypothesis! So maybe Iā€™m just getting random numbers right now.

@EZB Yes, always some glucose burn. But Lumen value 1 covers all the territory from .7-.76, so as Don says, it should be showing ā€˜1ā€™ all the time unless we purposely carb up.


(Windmill Tilter) #97

I wish! Iā€™ve got the budget model. Iā€™ve been underwhelmed by itā€™s RER measurements, which is why I am skeptical of the lumen.

The study I linked earlier took a baseline for all athletes at rest. The ā€œketogenicā€ subjects blew a .76. Bear in mind though, they had to eat a 15% carb diet in this study (donā€™t ask me why they call that ketogenic), and given that these were 180lb athletes at 11% bodyfat, Iā€™d guess that TDEE was easily 3000kcals. This would give us 450kcals, which is 112g carbs. I donā€™t think anybody here is eating 112g carbs!

Here is the table I was talking about where they had to adjust the RQ (same thing as RER but under strict measurement and resting protocols). The chart increases in size for clarity if you click on it. The RQ adjustment was way bigger than I remembered! By day 18 of water fasting, these guys were blowing a .628!!! Thatā€™s how they knew the readings from the $50,000 metabolic cart were bullshit. They made the adjustments on paper, and after day 1, these fellas all stayed at ~0.70 for the duration of the 18 days. In short though, being in deep ketosis caused underestimation rather than over-estimation.


(Windmill Tilter) #98

I think that makes sense. Iā€™m not trying to bust your chops or belittle the Lumen. My rig sucks for RER too. It had me at .75 while 3 days into a water fast. Thatā€™s not even humanly possible. Even the oneā€™s in metabolic wards struggle with RER once deep ketosis comes into play!

Iā€™m stuck with my rig, but youā€™re not stuck with the Lumen. Either it can measure the RER of people in ketosis or it canā€™t. It seems like itā€™s giving weird readings that donā€™t make sense to either of us. I think the Lumen folks have an obligation to answer questions about whether itā€™s capable of measuring RER of keto folks, and if not I think they have an obligation to refund your money. Or maybe a software patch can adjust the algorithm for ketosis, I donā€™t know. I think itā€™s worth asking them this stuff sooner rather than later if return is an option though. Iā€™m just trying to throw in what little I know about RER, but lord knows Iā€™m not an expert on any of this stuff.

Iā€™m guessing there are plenty of carb burners on the waiting list for whom it might be a better fit, and whoā€™d be thrilled to get a refurb model ahead of schedule. Itā€™s possible the algorithm is optimized for them.


(Michael - When reality fails to meet expectations, the problem is not reality.) #99

@Don_Q Thanks for pointing out those are rest values. Assuming Lumen numbers represent this:

1: =<.76 2: >.76 <.82 3: >.82 < .88 4: >.88 < .94 5: >.94 =<1.0

I want to admit that my first sampling was a total shock! How could I possibly have an RER >.82 and/or >.88 when I have consumed sub-15 grams of carbs nearly every day for the past 3+ years and many days only 10 grams or less! The Ketonix measurements confirmed ketosis. So either the device is junk or thereā€™s CO2 coming from somewhere other than fat burn. Before concluding the Lumen is junk, I want first to eliminate the alternative possibilities. So, where could other non-fat burn CO2 come from? Acetoacetate breakdown. Dayquil/Nyquil and/or Fishermanā€™s Friend.

Iā€™m going after acetoacetate breakdown first because I think thatā€™s the least likely source. 10 ppm is a very small amount. Iā€™m plotting sample results on a spreadsheet and already, itā€™s looking somewhat random. Maybe it will look less random with more samples. Weā€™ll see.

Iā€™m hoping that the combination of being ill and consuming overdoses of OTC meds to keep myself able to go to work will ultimately prove to be the source of the skewing. My last previous sample after my nap earlier supports this possibility. I had a powerful ā€˜breakā€™ in the current illness yesterday and overnight. I feel a lot better today than in more than a week. Maybe when I get over this, the Lumen samples will go to 1 and stay there. I certainly agree with you thatā€™s where it should.


(Michael - When reality fails to meet expectations, the problem is not reality.) #100

:face_with_monocle: The question of the moment!


(Ethan) #101

Yeah. Iā€™m underwhelmed by a few things. I blew a 3 on it today. This thing canā€™t deal with ketogenic diets. Then the thing tells me today will be a zero-carb dayā€”yet it says to eat 30g of carbs! Last time I checked zero isnā€™t equal to 30! That alone makes me want to smack the taste right out of their mouths


(Michael - When reality fails to meet expectations, the problem is not reality.) #102

To/From Lumen Support:

----Original Message----
I am in ketosis and have been continuously for 3+ years. Iā€™m getting unexpectedly high ā€˜carb burnā€™ readings from my Lumen (3-4). Is the Lumen capable of measuring RER in ketosis? If not, can the software be modified to enable it to do so? Thank you.

Hi Michael,

Thanks for reaching out.

I have analyzed your data and see Lumen could learn more about the range of your metabolism. Did you follow the calibration day guidelines regarding fasting before your morning measurement and then the high carb recommendations? It is via the calibration day that Lumen has an opportunity to learn about your unique metabolic scale.

To improve this I recommend the following -

Try to improve your flexibility by challenging your metabolism, this can be done by following the two protocols ( the order of the protocols is essential)

Protocol 1: The goal of this protocol is to stretch your metabolism and improve your flexibility toward using carbs as fuel source. Enjoy a high healthy carb meal (such as a nice bowl of legumes & rice/pasta) and then breath into your Lumen after 45-60 minutes.

Protocol 2: Keep taking your morning measurement and follow the app meal plan guidelines: The goal of this protocol is to stretch your metabolism and improve your flexibility toward using fat as fuel. For 1-3 days eat low carb and maintain a caloric deficit in your diet ( you can do so by following Lumenā€™s macro recommendations in your daily plan)

Try to have a good night sleep (at least 7 hours) each night.

Finish eating early each evening (ensure you fast for at least 10 hours).

And finally, relax before taking your measurements - Try taking a few breaths before you breath in order to fully relax your body and ensure you are in a non-stressful environment.

Lumen is indeed able to tell you if you are burning fat which happens well before appreciable levels of ketosis. Currently the application does not provide metrics such as RER to users, however, may do so in the future based on user requests. I recommend reading the following article

Please donā€™t hesitate to reach out if you have any further questions.

Best regards,
Aviv

I plan to respond to Aviv later today after I get home from work, if I have time. I may not until tomorrow, though because Wednesday afternoons and evenings are quite busy for me.


(Polly) #103

Sorry to be silly, but surely you already know you are burning fat as your fuel source.

ā€œIn this aspect the Lumen measurements in comparison to the ketosis results provide you with deeper information about your metabolism that can help you to achieve your weight or fitness goals.ā€

I would love to know what the deeper information about your metabolism is, and how you can find it without resorting to carb fuelling during calibration.


(Bob M) #104

Another issue I foresee is your own body over time. For instance, 4+ years ago when I was taking data, I would get 50-70 via Ketonix and BHB ketones via a blood meter (Precision Xtra first, then Keto Mojo) of well over 1.0 mmol/L.

Now, I blow in the 20s in Ketonix and am always below 0.5mmol/l in the morning. These are some of the values I got (to the right of time, keto mojo at home, keto mojo at work, ketonix, blood sugar):

image

Compare with a few years ago:

image

This must skew the results somehow.


(Michael - When reality fails to meet expectations, the problem is not reality.) #105

See above:


(Jenna Ericson) #106

Iā€™m sorry that youā€™ve been sick for so long. I think youā€™re right to connect this to your lower ketone levels and higher RER. While it sucks that youā€™re sick, I think we can learn something from your n=1. You said that in the spring/summer your BrAce was between 20 and 40 and recently your BrAce was 9.4 and Lumen 2 (and I understand your Lumen readings have been higher than that too).

My understanding is that your immune response is probably requiring a pretty constant supply of glucose to fight your illness. The interesting thing is, you are still in some level of ketosis even though it is a lower level than you are used to. Maybe this means that you are producing ketones to fuel your brain while also producing glucose to feed your immune response. Thatā€™s kinda amazing if itā€™s whatā€™s happening. I hope you get better soon (and not just so we can see how your numbers change) :blush:


(Ethan) #107

Well that is an interesting response. If you donā€™t want to eat carbs, just do a caloric deficit? I wonder what a 7-day fast would do


(Ethan) #108

Alsoā€¦ in the zero-carb meal plans is grilled duck breast with butter-glazed carrots. Do they know what a carb is?


(Windmill Tilter) #109

@amwassil

Iā€™m really intrigued by this idea, and your use of the Ketonix to correlate BrAce with the Lumen. You mentioned the use of cough syrup, and that youā€™ve been ill recently, and how you wondered how that might affect readings. You could be on to something. This article might be a piece of the puzzle. It summarizes ways in which certain foods and medications and other factors can affect BrACE levels within the body:

https://onlinelibrary.wiley.com/doi/full/10.1002/oby.21242


(Michael - When reality fails to meet expectations, the problem is not reality.) #110

I think Iā€™ve discovered a significant effect over the past two days re medication that affects RER, at least as measured by the Lumen.

As mentioned previously, I was taking some fairly large doses of Dayquil and Nyquil, both liquid and caplets to control my coughing. It enabled me to go to work and function. I stopped all *quil as of Feb17, prior to 4pm. I tested 0218: at 4pm, 7pm and 9pm. Results were all 2 on the Lumen. So my guess is that most of whatever the cough syrup was dumping into my system was metabolized out. I donā€™t think all of it yet, otherwise I suspect I would have blown 1s not 2s.

Last night (Feb18) before bed at 11pm I took a single Mucinex tablet. I also ate about 5 grams of raw ginger root just before taking the tablet. Today, I ate about 20-25 grams of raw ginger root (4-5 grams of carbs total) during my work shift to keep coughing under control. It worked, however, Iā€™ve tested 3 times today, 0219: at 5am, 3:30pm and 5pm. Results were all 3 on the Lumen. So either the Mucinex and/or ginger root have boosted CO2 again. I hope not as much as the cough syrup.

I am off both tomorrow and Friday, so I do not have to medicate myself to prevent coughing. I am hoping that a couple of ā€˜cleanā€™ days will burn out whatever is still lingering. Also, the wife and I are going to our local rec center tonight, she for swim lesson and I for the sauna and hot tub. So maybe Iā€™ll blow some 1s before the weekend. :+1:


(Michael - When reality fails to meet expectations, the problem is not reality.) #111

Iā€™ve been wondering about ā€˜calibrationā€™ and I think Iā€™ve figured out whatā€™s going on. First off, whatā€™s to ā€˜calibrateā€™? If you measure O2 in and CO2 out, RER is just the mathematical ratio of those two values somewhere within the range of .70 to 1.0.

So why didnā€™t Lumen just design and build a device that calculates absolute RER? I think because the market for such a device would be fairly limited. Us gadget guys and gals, maybe some university labs and training facilities and a few top athletes.

But if you build such a device how do you market it (and make big bucks) to a wider audience who probably donā€™t know and likely donā€™t care what RER is? But who do care about losing weight and probably need help to do it. You market a consulting service based on using said device as a yard stick and gimmick.

Average overweight Joe and Jill eating some variation of SAD donā€™t have a realistic RER range much beyond .80 - .90 and probably spend most of their lives at .85. So thereā€™s really no need to display the absolute range of RER. You only have to give Joe and Jill something attractive and encouraging to look at multiple times per day.

Thus: Calibration! You have Joe and Jill fast overnight to get whatever the lowest RER they can blow. If they actually get into ketosis, great. But itā€™s not necessary, we just need a relative min value. Then during the day we have Joe and Jill carb up to get whatever highest RER they can blow by the end of the day. Again the absolute number does not matter, we just need a relative max value. Then our ā€˜smartā€™ software takes the min and max values, divides the range into 5 equal segments. VoilĆ ! A customized, calibrated RER value set.

So what happens when some smart aleck like me comes along whoā€™s been in ketosis for 3+ years and has no intention of carbing up. The device still calibrates a min and max value and divides the range into 5 equal segments. But in my case the range is probably something like .72 - .76.

What do you think? Plausible?


Mike's Excellent Glucose Monitor Adventure
(Polly) #112

More than plausible, @amwassil I would say probable that you have hit the nail on the head!

When I read the letter they had emailed to you yesterday, I actually wondered what the device was measuring and calculating at all but now you have seen through the smoke and mirrors it makes sense to me.

Well done.

Will you now record your data in a spreadsheet so it can do what you want it to do?