7 ms·

Continuous glucose monitors reveal variable glucose responses to the same meals

201 points by Matrixik 1y ago

msarrel 1y ago
Fascinating. I've always felt that this was true with my own body, yet every medical professional I've spoken to said that I was wrong.
- jzacharia 1y ago
  Hate to sound like "that guy" but a majority of medical professionals are running their practice on outdated data or false studies funded by pharma.
  - nradov 1y ago
    There are problems in the US healthcare system with slow adoption of clinical practice guidelines and lack of research funding for non-pharmaceutical treatments. But on an objective scientific basis the recent studies funded by pharma tend to be some of the highest quality work. They have huge budgets and are held to fairly high standards now by the FDA so we tend to see large subject populations, multiple sites, proper controls, and rigorous statistical analysis.
zingababba 1y ago
"Additionally, the summarized study did not record the timing of snack and water consumption. This is relevant because the sequence and timing of subsequent meals (or snacks), as well as the food processing and variability, can influence postmeal glucose responses." - probably a factor, hydration status is huge. This result is kind of like 'duh' though. https://pubmed.ncbi.nlm.nih.gov/28739050/ https://pubmed.ncbi.nlm.nih.gov/28739050/
- hinkley 1y ago
  Hydration, activity and stress levels. Adrenal responses can pause the digestive process to conserve energy for fight or flight. Muscle use also diverts resources, stressed or not. And being dehydrated essentially concentrates everything in your blood, complicating kidney and liver function.
ggandv 1y ago
80% of the variation due to individual differences OR measurement error.
taeric 1y ago
Odd, I would have expected this to be somewhat the case? Specifically, I would expect your activity leading into the meals, along with your expectations of what you will be doing after, would have some impact? Probably more impact from how hungry you were going into a meal. If you were already sated, for example, I'd expect your body to largely try and push the meal through as fast as it can. Neat to see what other people's priors are, on this.
- pfortuny 1y ago
  People think medicine is Physics. They really do.
  - taeric 1y ago
    I think I agree with the idea you are saying. That people think you can formulate our body to ignore a lot of the state that it holds. I'll note that even basic physics has that problem. Try explaining to a 5th grader why a feather would fly in the same arc that a rock will take, if there was no air.
    - pfortuny 1y ago
      Well, I did not want to say "Mathematics" because it sounded a bit exaggerated. Of course you are right.
- blitzar 1y ago
  Non expert here ... My understanding was sleep, stress and many other variables all impact these things significantly (before we even consider food). Having a different context when you then add the same food thus should not result in the same outcome.
- perrygeo 1y ago
  I'm very sensitive to sugar and starch when "at rest". If I wake up first thing in the morning and drink an orange juice or have a bowl of white rice before bed, my blood sugar and mood are out of control. But the same foods mid-day before/after/during intense mental or physical work are very well tolerated if not beneficial. So my priors agree with yours, timing and context absolutely matters.
stranded22 1y ago
Yep. My wife is T1D and this is infuriating for her. She’ll think that she’s cracked it, and then the next day, with the same meal at the same time, her sugar levels go high. Her words: there is nothing else where you have studied for over 30 years and STILL feel like you know nothing. It is incredibly demoralising for her sometimes - especially when she’s suffering also from a high/low sugar level. I have the upmost respect for anyone having to do the amount of work, to get to zero (sometimes).
- deleted 1y ago
  [deleted]
- ddorian43 1y ago
  How about just not eat carbs at all and have more consistent & lower blood sugar? (this was an interesting case https://www.youtube.com/watch?v=CG8UU7P8FBU https://www.youtube.com/watch?v=CG8UU7P8FBU) I do keto diet long term but for other reasons, often the epilepsy version where it's more strict and higher fat.
  - jzacharia 1y ago
    Keto works well, but I'm concerned about the extreme fat intake. I did manage to lower my A1C from 9s to mid 5s using Keto as a T1D, but eventually settled into a high protein, moderate fat, low-ish carb diet and that has worked pretty well without being hyper-restrictive. Heavily inspired by the late Dr. Richard K. Bernstein.
    - ddorian43 1y ago
      I target for high ketones (1.5+) & low glucose 4-5mmol (blood test 1 hour after wake up) and higher protein interferes with both of them.
      - jzacharia 1y ago
        Curious - what's the reason for targeting ketone levels?
csours 1y ago
Some assumptions are so obvious no one bothers to state them, or even remember them. Assumption: Medical professionals are trained to use Evidence Based Medicine (EBM). One might assume that EBM means something specific, and I'm sure it does, but that specific thing is different for different people. One thing that EBM sometimes means is: common sense is no substitute for evidence. There are uncountable times that common sense has been wrong in the medical context. So, you have a lot of people commenting here that this is obvious common sense, but many medical professionals will pull out a reference chart of caloric content and glycemic index and say "look at the evidence". So, it is very useful to do studies that bring evidence to common sense. --- My other pet peeve with EBM is that it does a poor job of understanding that different interventions work for different people - it is time consuming and expensive to do that kind of investigation, thus some/many medical professionals do not understand or believe it. This comment is intended as a critique, not a dismissal.
- blitzar 1y ago
  It is wonderful that we have things like CGM's and patients can establish their own baselines and their own evidence profiles on a high(ish) frequency basis. Such tools also enable studies that can be done at a scale and cost level that is reasonable and can push forward the communal knowledge base.
  - csours 1y ago
    Yup, and this was the original dream of Theranos - lots of measurements, lots of data. It's a nice dream, shame about the lies though.
  - Taikonerd 1y ago
    This is the idea behind the "Zoe" service: https://zoe.com/en-us https://zoe.com/en-us 1. You wear a CGM for 2 weeks, and log everything you eat. 2. At the end, you get a personalized report about how different foods that you ate affect you, personally. And they can extrapolate to other foods that you didn't eat during the testing period. 3. Zoe's model gets better and better the more people sign up, and the more data they get.
endoblast 1y ago
One factor that scientific food experiments don't seem to include is gluttony. Presumably because it is subjective (though nonetheless real for that). Yet if people are motivated by the amount of comfort and/or pleasure they obtain from eating their favourite foods this may have an effect on their physiological response.
- endoblast 1y ago
  I realise the word 'gluttony' is off-putting (for atheists for instance) but I don't know a better one. Perhaps 'over-excitement'? The symptoms of excitement are of course similar to the fight-or-flight response. Raised heart rate for one. Butterflies in the stomach indicate release of adrenaline, which in turn raises blood glucose -- not from the food being eaten but from the body's stores. So there's a link right there. How excited you are about a given food will depend not only upon the foodstuff itself but also on your personal taste and personal history. If you have taken pleasure in its consumption many times in the past this may affect your present level of excitement. 'Arousal' is another word that just sprang to mind.
francisofascii 1y ago
Sounds expected? If you are glycogen depleted, it will cause less of an insulin spike. This sounds like if you fill up the same type of car with 5 gallons of gas. Sometimes it reports full, and sometimes it doesn't. That sounds odd, until you accept that you are never fully sure the gas level you started at.
blindriver 1y ago
I've been diagnosed with Type 2 diabetes and wear a CGM. I find that my blood glucose spikes much later than what is suggested. For example, I might eat a meal and my blood glucose doesn't spike until after 2 hours. When it spikes, I see the body react with insulin and it drives my blood sugar levels down, so I'm not sure if I actually do have T2D or if this is just how my body works. Another thing I've noticed is that if I eat a very rice-heavy meal, my blood sugar levels may rise throughout the night. I don't think this is insulin-resistance but rather my body digesting the rice. You can't expect the body to digest all the rice in 2 hours, can you, there certainly must be parts that are protected from the stomach acid until much later in the digestion process. So that feeds into the high blood sugar levels overnight in my opinion. I think if anything, CGMs have opened up the idea of what diabetes really is and how different bodies handle blood sugar. I think I'm borderline T2D, not full-on T2D despite what my doctor says, and I've started wondering if my blood sugar has always been high, but normal for me. On average it's about 120 mg/dL, but I do see my body react properly to new sources of blood sugar and drive it back to "normal" levels, so the idea that I have insulin resistance doesn't make sense to me.
- bobmcnamara 1y ago
  Do you know if you do(not) have delayed gastric emptying?
- bilsbie 1y ago
  Interesting. What’s your a1c level ? I think you could have a point at around 100-105 baseline but 120 seems too high.
  - blindriver 1y ago
    It's high, like 6.7-6.9. It doesn't make sense to me because that would suggest average blood glucose of over 150, but it's objectively around 120.
    - nradov 1y ago
      There is some genetic variability in the correlation between blood glucose versus HbA1c. The HbA1c test is essentially an integrator of blood glucose level over time but different people have different average red blood cell lifespans.
jzacharia 1y ago
Shouldn't come as a surprise - there are so many factors involved in glucose response to food that it's almost impossible to replicate a glucose response even with a controlled intake. Sleep, activity levels (before, after, during, even days before, etc), stress, hormones, all of these are major factors involved in how glucose is metabolized.
- burnt-resistor 1y ago
  Chewing, acid production, gut microbiome, and possibly more. I think it will/would take a lot of data to uncover the most important factor(s).
siliconc0w 1y ago
Is this already pretty expected? We already knew that glucose response was highly dependent on time of day, pre or post meal movement, and whether the meal is moderated by other components like fats that can slow down the immediate impact.
GiorgioG 1y ago
As the parent of a type 1 diabetic...all I can say is "duh, no shit." Activity levels, emotional state, how much time between eating & bedtime, agem among other things affect glucose response.
slwvx 1y ago
Jessie Inchauspe [1] created a business (she's the "glucose goddess") and wrote books around the different blood sugar responses she and others have to meals, exercise, etc... I don't recall all the ideas, but here are the two I remember: Exercise before and/or after eating smooths out the blood sugar response to food. When eating a meal, it's better to eat high-fiber stuff first, then complex carbs, then protein, then fats, and eat simple carbs last (Or something like that order). [1] https://en.wikipedia.org/wiki/Jessie_Inchauspé https://en.wikipedia.org/wiki/Jessie_Inchauspé
- electrondood 1y ago
  GLUT-4 activation in the muscles primes them to take up glucose and other nutrients. So air squats or going for a walk before/after a meal can significantly blunt the insulin response, because there's less glucose in your blood stream, because more of it has been ported into muscles.
- goldchainposse 1y ago
  Is the order salad, baked potato, steak, dessert?
  - slwvx 1y ago
    Yeah, I think so, though my recollection is that a baked potato's glycemic index is kinda high. For more authoritative list of details, you could listen to the following podcast with Inchauspé: https://overcast.fm/+AA4G32XuwoA https://overcast.fm/+AA4G32XuwoA
Imme_Play_5550 1y ago
My mother and I recently did an oral glucose tolerance test while wearing CGMs and discovered that in us, the CGM measurements (Dexcom G7) and the reference instrument measurements (whatever Quest Diagnostics uses) virtually _never_ lined up, even when including the G7's advertised error margins. The blood glucometer readings in me didn't line up either. Admittedly this was on the first day using the G7, when it's apparently less accurate, but due to this I've been doubtful of CGM readings in me/her. I'm sure CGMs work on a population level, but for us, on that day? Nope. My graph: https://i.imgur.com/FzPdH1g.png https://i.imgur.com/FzPdH1g.png Mom's graph: https://i.imgur.com/5DR1G30.png https://i.imgur.com/5DR1G30.png Discussion: https://reddit.com/r/PeterAttia/comments/1k301o4/my_ogtt_experience_or_how_i_learned_that/ https://reddit.com/r/PeterAttia/comments/1k301o4/my_ogtt_exp...
mahgnous 1y ago
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aucisson_masque 1y ago
> if an individual eats the same meal on two occasions but starts with the vegetables on one occasion but not the other, this may lead to different glucose responses to the same meal within the same individual. > Other behavioral and individual factors are known to influence CGM responses.[22][6] Postmeal physical activity — even as minor as leg fidgeting[23] and walking for a few minutes every hour — reduces postmeal glucose responses.[24] Sleep quality has also been associated with changes in postmeal CGM glucose responses.[25] Emerging studies are also uncovering the relationship between an individual’s gut microbiome and their postmeal glycemic responses.[26][27][28] So basically it's the impact of the parasympathetic/sympathetic nervous system and the order of food ingestion that could induce different glucose response. It's interesting because I assumed that beside the nervous system, whatever order we eat our food, it all mixes in the stomach and then start to process. Negating the importance of order but studies implies it does.
- NoPicklez 1y ago
  It is interesting, but it has been long well "known" that if you eat the more fibrous foods first this effectively slows the digestion of what comes next.
pedalpete 1y ago
Blood glucose is dependent on more variables than just what you eat. Decreased sleep slow-wave activity (not just sleep time, but the actual restorative function of sleep) significantly decreases next day insulin response [1]. This is my area (I work in neurotech/sleeptech), but other things that come to mind are changes in changes in gut biome, which can be altered by previous meals, and I assume is always in flux (not my area of expertise), hormonal changes, I'm sure there are others. However, the conclusion that it undermines the CGM measurements. In fact, I think this makes CGMs more valuable, not less. For those without diabetes, I always thought you'd use the CGM for a few weeks, figure out what your body responds to, and then sort out your diet. This shows that it isn't that simple, and that we likely need to be monitoring more regularly. If my breakfast spiked my glucose unexpectedly, that may be a signal that I should change my lunch in order to reduce the likelihood of another spike. It becomes about constant management, rather than a 1 time look under the hood. https://doi.org/10.1016/j.sleep.2022.03.005 https://doi.org/10.1016/j.sleep.2022.03.005
- esperent 1y ago
  > For those without diabetes, I always thought you'd use the CGM for a few weeks, figure out what your body responds to, and then sort out your diet. This was my plan sometime in the next few months. I think it's still a valid plan, just with some caveats. Anyway due to cost and annoyance I'm unlikely to wear a CGM for more than a couple of months. But that should be enough time to get usable data - like all body tracking data, I'll end up using it as guidance rather than rule. The caveats are that I'll also need to track my sleep and workouts during that time and carefully look for patterns in the data related to all three. I already know sleep and workouts are strongly correlated and not always in the way you'd expect. I did a strong HIIT class at 6pm last night, and due to a bit of crunch on personal projects it was my first proper workout in a week. My sleep tracker (Galaxy Watch 6) gave me a very poor sleep and energy score. 61/100 for sleep, 69/100 for energy. I normally score high eighties to low 90s in both. These scores usually but not always match with my actual feeling. But today I also feel tired (it's 8am here now). If I had a CGM, I'd also be keeping a strong eye out for unusual glucose response today. This is more complex than I'd like it to be - I wish my body was as simple to read as just getting a single number like glucose response and making adjustments from that! But as a lifelong migraine sufferer who now has my migraines almost entirely under control by making lifestyle changes, I'm well aware that how my body responds is always a combination of many things. Stormy weather + ate cheese + slightly too strong coffee + stress from work = boom, migraine. Take away any one of those and maybe I wouldn't have got one. I fully expect my body's glucose response to be just as complex.
FollowingTheDao 1y ago
I wish they would’ve checked insulin response along with the glucose response.
utopcell 1y ago
Here's a (Gemini) AI summary that seems to be capturing the main point that the article wants to convey. ``` This page summarizes a study about continuous glucose monitors (CGMs) and how individuals can have highly variable glucose responses even when eating the same meals. The study, which involved 30 participants without diabetes, found a weak-to-moderate correlation between glucose responses to identical meals, with about 80% of the variation attributed to within-participant differences or measurement error. The article notes that high glucose variability is linked to increased risk of death, greater hunger, and poorer mental health and sleep. While CGMs are beneficial for people with diabetes to prevent hypoglycemic episodes, this study suggests that developing personalized nutrition recommendations for glycemic control may be more complex than previously thought due to inconsistent individual responses. The authors emphasize the need for more reliable dietary assessment and a deeper understanding of the behavioral, dietary, and individual factors that influence glucose responses. ```
utopcell 1y ago
It would be unfortunate if this article were to discourage folks from trying CGMs out. I am not diabetic but have found a lot of value in using a Stelo CGM sensor. At minimum, it gives me awareness of my current state. I routinely check it before considering desserts for example. Also, I was shocked at the spikes I would get from some food. Maybe an "obvious in retrospect" feedback was drinking a bottle of (non-diet) Coke. It consistently gave me 50 unit spikes (mg/dL). Nothing came close to it, including large meals or meals + desserts. On the other hand, drinking diet coke had absolutely no impact, which was contrary to what I've read before (the body is confused and produces insulin). Another surprising observation is the effect of consuming Feta (a particular kind of Greek cheese) : no matter what else I may have eaten, a piece of feta always leads to a reduction of 10 to 20 points for at least half an hour after consuming it(!) I doubt this is generally true, which speaks to each body reacting differently.
esdott 1y ago
As a long time diabetic (t1d) with direct relatives also afflicted with this horrible disease, it’s frustrating that we often miss the key factors in insulin resistance and fail to see how they fit in. The level of serotonin and its interplay with our current level of immune response/inflammation in our body is the single best predictor of insulin resistance. That’s simply because every good thing you can do to lower resistance increases serotonin. Serotonin then decreases inflammation. When you exercise for a long period of time you are not only increasing your immediate availability of serotonin, you are also increasing your daily availability for serotonin. Obviously it’s a little more complicated but from a big picture standpoint, either something is increasing inflammation in you today and increasing your insulin resistance or (hopefully) the opposite is happening and serotonin is moving your insulin through your blood stream like a mag lev train. On a side note, I do love cgms.
sinuhe69 1y ago
What about the famous breakfast? One prevalent theory among nutritionists is that the breakfast has huge influence on the insulin responses during the day: a low carb/no sugar, high protein and fat breakfast will not spike your blood glucose level and therefore will lead to a more moderate response to meal intake during the day as opposite to a high carb breakfast. I think the study should control this variable as well.
Klaus_ 1y ago
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lytefm 1y ago
I've been working in this space for seven years, this isn't new. There have been big studies from the UK in 2020 [1] and Israel in 2015 [2] about this. Some of my learnings: - Don't start your day with a large amount carbs. Have some insulin in your blood before eating that big bowl of oatmeal. Or just go for some yougurt with nuts and seeds. - The classical order of a three course meal (salad first, then main dish, then dessert) is pretty good in terms of preventing glucose spikes. - Going for a walk after a meal is great for bringing glucose levels down. - Eat at least 2h before going to sleep. Having high glucose levels disrupts sleep. - Alcohol lowers the glucose response of a meal, but is still bad unfortunately. - Diet Coke works. No spike vs loads of sugar with a real coke. - Stress can spike glucose like crazy, e.g. being in an interview or during takeoff. - If you really want to know how you react to some food, keep the circumstances (time of day, sleep, physical activity, stress) similar. There's too much influence beyond just the meal. I bet that everyone who is wearing a premium smartwatch or an Oura ring now will be using a CGM now and then in the next years. [1]: https://pubmed.ncbi.nlm.nih.gov/32528151/ https://pubmed.ncbi.nlm.nih.gov/32528151/ [2]: https://pubmed.ncbi.nlm.nih.gov/26590418/ https://pubmed.ncbi.nlm.nih.gov/26590418/
kristel100 1y ago
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whycome 1y ago
I like the idea that the proliferation of LLMs become frameworks for understanding that can help advance a field or help curious thinkers come up with novel hypotheses. If the body is something like a trained model, it’s not crazy to think that it will respond to something like fake sugar (eg aspartame) with biological processes that would only be expected for real sugar.
turnsout 1y ago
Leaving aside the science, this paper draws the wrong conclusion. Just because many factors influence BG response does not mean CGMs are somehow invalid as a tool for personalized nutrition. Quite the opposite. A good nutritionist does not work in a vacuum. They know the holistic nature of BG and will tailor their recommendations to the patient based on lifestyle. (I worked on a holistic diabetes management platform)
jadeisokay 1y ago
i'm a type one diabetic. this is uh, not news to me. i can eat the same thing every single day at the same time and see different numbers after every meal. stress, hydration, heat/cold, fatigue, if the wind is blowing, so many other things affect blood sugar.
fcpk 1y ago
Sorry to complain, but what the hell is this horrible AI summary link? The actual study is not open, but surely enough something a bit more precise could be given.

201 points by Matrixik 1y ago

Fascinating. I've always felt that this was true with my own body, yet every medical professional I've spoken to said that I was wrong.

jzacharia 1y ago
Hate to sound like "that guy" but a majority of medical professionals are running their practice on outdated data or false studies funded by pharma.
- nradov 1y ago
  There are problems in the US healthcare system with slow adoption of clinical practice guidelines and lack of research funding for non-pharmaceutical treatments. But on an objective scientific basis the recent studies funded by pharma tend to be some of the highest quality work. They have huge budgets and are held to fairly high standards now by the FDA so we tend to see large subject populations, multiple sites, proper controls, and rigorous statistical analysis.

zingababba 1y ago

"Additionally, the summarized study did not record the timing of snack and water consumption. This is relevant because the sequence and timing of subsequent meals (or snacks), as well as the food processing and variability, can influence postmeal glucose responses." - probably a factor, hydration status is huge. This result is kind of like 'duh' though. https://pubmed.ncbi.nlm.nih.gov/28739050/ https://pubmed.ncbi.nlm.nih.gov/28739050/

hinkley 1y ago
Hydration, activity and stress levels. Adrenal responses can pause the digestive process to conserve energy for fight or flight. Muscle use also diverts resources, stressed or not. And being dehydrated essentially concentrates everything in your blood, complicating kidney and liver function.

ggandv 1y ago

80% of the variation due to individual differences OR measurement error.

taeric 1y ago

Odd, I would have expected this to be somewhat the case? Specifically, I would expect your activity leading into the meals, along with your expectations of what you will be doing after, would have some impact? Probably more impact from how hungry you were going into a meal. If you were already sated, for example, I'd expect your body to largely try and push the meal through as fast as it can. Neat to see what other people's priors are, on this.

pfortuny 1y ago
People think medicine is Physics. They really do.
- taeric 1y ago
  I think I agree with the idea you are saying. That people think you can formulate our body to ignore a lot of the state that it holds. I'll note that even basic physics has that problem. Try explaining to a 5th grader why a feather would fly in the same arc that a rock will take, if there was no air.
  - pfortuny 1y ago
    Well, I did not want to say "Mathematics" because it sounded a bit exaggerated. Of course you are right.
blitzar 1y ago
Non expert here ... My understanding was sleep, stress and many other variables all impact these things significantly (before we even consider food). Having a different context when you then add the same food thus should not result in the same outcome.
perrygeo 1y ago
I'm very sensitive to sugar and starch when "at rest". If I wake up first thing in the morning and drink an orange juice or have a bowl of white rice before bed, my blood sugar and mood are out of control. But the same foods mid-day before/after/during intense mental or physical work are very well tolerated if not beneficial. So my priors agree with yours, timing and context absolutely matters.

stranded22 1y ago

Yep. My wife is T1D and this is infuriating for her. She’ll think that she’s cracked it, and then the next day, with the same meal at the same time, her sugar levels go high. Her words: there is nothing else where you have studied for over 30 years and STILL feel like you know nothing. It is incredibly demoralising for her sometimes - especially when she’s suffering also from a high/low sugar level. I have the upmost respect for anyone having to do the amount of work, to get to zero (sometimes).

deleted 1y ago
[deleted]
ddorian43 1y ago
How about just not eat carbs at all and have more consistent & lower blood sugar? (this was an interesting case https://www.youtube.com/watch?v=CG8UU7P8FBU https://www.youtube.com/watch?v=CG8UU7P8FBU) I do keto diet long term but for other reasons, often the epilepsy version where it's more strict and higher fat.
- jzacharia 1y ago
  Keto works well, but I'm concerned about the extreme fat intake. I did manage to lower my A1C from 9s to mid 5s using Keto as a T1D, but eventually settled into a high protein, moderate fat, low-ish carb diet and that has worked pretty well without being hyper-restrictive. Heavily inspired by the late Dr. Richard K. Bernstein.
  - ddorian43 1y ago
    I target for high ketones (1.5+) & low glucose 4-5mmol (blood test 1 hour after wake up) and higher protein interferes with both of them.
    - jzacharia 1y ago
      Curious - what's the reason for targeting ketone levels?

csours 1y ago

Some assumptions are so obvious no one bothers to state them, or even remember them. Assumption: Medical professionals are trained to use Evidence Based Medicine (EBM). One might assume that EBM means something specific, and I'm sure it does, but that specific thing is different for different people. One thing that EBM sometimes means is: common sense is no substitute for evidence. There are uncountable times that common sense has been wrong in the medical context. So, you have a lot of people commenting here that this is obvious common sense, but many medical professionals will pull out a reference chart of caloric content and glycemic index and say "look at the evidence". So, it is very useful to do studies that bring evidence to common sense. --- My other pet peeve with EBM is that it does a poor job of understanding that different interventions work for different people - it is time consuming and expensive to do that kind of investigation, thus some/many medical professionals do not understand or believe it. This comment is intended as a critique, not a dismissal.

blitzar 1y ago
It is wonderful that we have things like CGM's and patients can establish their own baselines and their own evidence profiles on a high(ish) frequency basis. Such tools also enable studies that can be done at a scale and cost level that is reasonable and can push forward the communal knowledge base.
- csours 1y ago
  Yup, and this was the original dream of Theranos - lots of measurements, lots of data. It's a nice dream, shame about the lies though.
- Taikonerd 1y ago
  This is the idea behind the "Zoe" service: https://zoe.com/en-us https://zoe.com/en-us 1. You wear a CGM for 2 weeks, and log everything you eat. 2. At the end, you get a personalized report about how different foods that you ate affect you, personally. And they can extrapolate to other foods that you didn't eat during the testing period. 3. Zoe's model gets better and better the more people sign up, and the more data they get.

endoblast 1y ago

One factor that scientific food experiments don't seem to include is gluttony. Presumably because it is subjective (though nonetheless real for that). Yet if people are motivated by the amount of comfort and/or pleasure they obtain from eating their favourite foods this may have an effect on their physiological response.

endoblast 1y ago
I realise the word 'gluttony' is off-putting (for atheists for instance) but I don't know a better one. Perhaps 'over-excitement'? The symptoms of excitement are of course similar to the fight-or-flight response. Raised heart rate for one. Butterflies in the stomach indicate release of adrenaline, which in turn raises blood glucose -- not from the food being eaten but from the body's stores. So there's a link right there. How excited you are about a given food will depend not only upon the foodstuff itself but also on your personal taste and personal history. If you have taken pleasure in its consumption many times in the past this may affect your present level of excitement. 'Arousal' is another word that just sprang to mind.

francisofascii 1y ago

Sounds expected? If you are glycogen depleted, it will cause less of an insulin spike. This sounds like if you fill up the same type of car with 5 gallons of gas. Sometimes it reports full, and sometimes it doesn't. That sounds odd, until you accept that you are never fully sure the gas level you started at.

blindriver 1y ago

I've been diagnosed with Type 2 diabetes and wear a CGM. I find that my blood glucose spikes much later than what is suggested. For example, I might eat a meal and my blood glucose doesn't spike until after 2 hours. When it spikes, I see the body react with insulin and it drives my blood sugar levels down, so I'm not sure if I actually do have T2D or if this is just how my body works. Another thing I've noticed is that if I eat a very rice-heavy meal, my blood sugar levels may rise throughout the night. I don't think this is insulin-resistance but rather my body digesting the rice. You can't expect the body to digest all the rice in 2 hours, can you, there certainly must be parts that are protected from the stomach acid until much later in the digestion process. So that feeds into the high blood sugar levels overnight in my opinion. I think if anything, CGMs have opened up the idea of what diabetes really is and how different bodies handle blood sugar. I think I'm borderline T2D, not full-on T2D despite what my doctor says, and I've started wondering if my blood sugar has always been high, but normal for me. On average it's about 120 mg/dL, but I do see my body react properly to new sources of blood sugar and drive it back to "normal" levels, so the idea that I have insulin resistance doesn't make sense to me.

bobmcnamara 1y ago
Do you know if you do(not) have delayed gastric emptying?
bilsbie 1y ago
Interesting. What’s your a1c level ? I think you could have a point at around 100-105 baseline but 120 seems too high.
- blindriver 1y ago
  It's high, like 6.7-6.9. It doesn't make sense to me because that would suggest average blood glucose of over 150, but it's objectively around 120.
  - nradov 1y ago
    There is some genetic variability in the correlation between blood glucose versus HbA1c. The HbA1c test is essentially an integrator of blood glucose level over time but different people have different average red blood cell lifespans.

jzacharia 1y ago

Shouldn't come as a surprise - there are so many factors involved in glucose response to food that it's almost impossible to replicate a glucose response even with a controlled intake. Sleep, activity levels (before, after, during, even days before, etc), stress, hormones, all of these are major factors involved in how glucose is metabolized.

burnt-resistor 1y ago
Chewing, acid production, gut microbiome, and possibly more. I think it will/would take a lot of data to uncover the most important factor(s).

siliconc0w 1y ago

Is this already pretty expected? We already knew that glucose response was highly dependent on time of day, pre or post meal movement, and whether the meal is moderated by other components like fats that can slow down the immediate impact.

GiorgioG 1y ago

As the parent of a type 1 diabetic...all I can say is "duh, no shit." Activity levels, emotional state, how much time between eating & bedtime, agem among other things affect glucose response.

slwvx 1y ago

Jessie Inchauspe [1] created a business (she's the "glucose goddess") and wrote books around the different blood sugar responses she and others have to meals, exercise, etc... I don't recall all the ideas, but here are the two I remember: Exercise before and/or after eating smooths out the blood sugar response to food. When eating a meal, it's better to eat high-fiber stuff first, then complex carbs, then protein, then fats, and eat simple carbs last (Or something like that order). [1] https://en.wikipedia.org/wiki/Jessie_Inchauspé https://en.wikipedia.org/wiki/Jessie_Inchauspé

electrondood 1y ago
GLUT-4 activation in the muscles primes them to take up glucose and other nutrients. So air squats or going for a walk before/after a meal can significantly blunt the insulin response, because there's less glucose in your blood stream, because more of it has been ported into muscles.
goldchainposse 1y ago
Is the order salad, baked potato, steak, dessert?
- slwvx 1y ago
  Yeah, I think so, though my recollection is that a baked potato's glycemic index is kinda high. For more authoritative list of details, you could listen to the following podcast with Inchauspé: https://overcast.fm/+AA4G32XuwoA https://overcast.fm/+AA4G32XuwoA

Imme_Play_5550 1y ago

My mother and I recently did an oral glucose tolerance test while wearing CGMs and discovered that in us, the CGM measurements (Dexcom G7) and the reference instrument measurements (whatever Quest Diagnostics uses) virtually _never_ lined up, even when including the G7's advertised error margins. The blood glucometer readings in me didn't line up either. Admittedly this was on the first day using the G7, when it's apparently less accurate, but due to this I've been doubtful of CGM readings in me/her. I'm sure CGMs work on a population level, but for us, on that day? Nope. My graph: https://i.imgur.com/FzPdH1g.png https://i.imgur.com/FzPdH1g.png Mom's graph: https://i.imgur.com/5DR1G30.png https://i.imgur.com/5DR1G30.png Discussion: https://reddit.com/r/PeterAttia/comments/1k301o4/my_ogtt_experience_or_how_i_learned_that/ https://reddit.com/r/PeterAttia/comments/1k301o4/my_ogtt_exp...

mahgnous 1y ago

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aucisson_masque 1y ago

> if an individual eats the same meal on two occasions but starts with the vegetables on one occasion but not the other, this may lead to different glucose responses to the same meal within the same individual. > Other behavioral and individual factors are known to influence CGM responses.[22][6] Postmeal physical activity — even as minor as leg fidgeting[23] and walking for a few minutes every hour — reduces postmeal glucose responses.[24] Sleep quality has also been associated with changes in postmeal CGM glucose responses.[25] Emerging studies are also uncovering the relationship between an individual’s gut microbiome and their postmeal glycemic responses.[26][27][28] So basically it's the impact of the parasympathetic/sympathetic nervous system and the order of food ingestion that could induce different glucose response. It's interesting because I assumed that beside the nervous system, whatever order we eat our food, it all mixes in the stomach and then start to process. Negating the importance of order but studies implies it does.

NoPicklez 1y ago
It is interesting, but it has been long well "known" that if you eat the more fibrous foods first this effectively slows the digestion of what comes next.

pedalpete 1y ago

Blood glucose is dependent on more variables than just what you eat. Decreased sleep slow-wave activity (not just sleep time, but the actual restorative function of sleep) significantly decreases next day insulin response [1]. This is my area (I work in neurotech/sleeptech), but other things that come to mind are changes in changes in gut biome, which can be altered by previous meals, and I assume is always in flux (not my area of expertise), hormonal changes, I'm sure there are others. However, the conclusion that it undermines the CGM measurements. In fact, I think this makes CGMs more valuable, not less. For those without diabetes, I always thought you'd use the CGM for a few weeks, figure out what your body responds to, and then sort out your diet. This shows that it isn't that simple, and that we likely need to be monitoring more regularly. If my breakfast spiked my glucose unexpectedly, that may be a signal that I should change my lunch in order to reduce the likelihood of another spike. It becomes about constant management, rather than a 1 time look under the hood. https://doi.org/10.1016/j.sleep.2022.03.005 https://doi.org/10.1016/j.sleep.2022.03.005

esperent 1y ago
> For those without diabetes, I always thought you'd use the CGM for a few weeks, figure out what your body responds to, and then sort out your diet. This was my plan sometime in the next few months. I think it's still a valid plan, just with some caveats. Anyway due to cost and annoyance I'm unlikely to wear a CGM for more than a couple of months. But that should be enough time to get usable data - like all body tracking data, I'll end up using it as guidance rather than rule. The caveats are that I'll also need to track my sleep and workouts during that time and carefully look for patterns in the data related to all three. I already know sleep and workouts are strongly correlated and not always in the way you'd expect. I did a strong HIIT class at 6pm last night, and due to a bit of crunch on personal projects it was my first proper workout in a week. My sleep tracker (Galaxy Watch 6) gave me a very poor sleep and energy score. 61/100 for sleep, 69/100 for energy. I normally score high eighties to low 90s in both. These scores usually but not always match with my actual feeling. But today I also feel tired (it's 8am here now). If I had a CGM, I'd also be keeping a strong eye out for unusual glucose response today. This is more complex than I'd like it to be - I wish my body was as simple to read as just getting a single number like glucose response and making adjustments from that! But as a lifelong migraine sufferer who now has my migraines almost entirely under control by making lifestyle changes, I'm well aware that how my body responds is always a combination of many things. Stormy weather + ate cheese + slightly too strong coffee + stress from work = boom, migraine. Take away any one of those and maybe I wouldn't have got one. I fully expect my body's glucose response to be just as complex.

FollowingTheDao 1y ago

I wish they would’ve checked insulin response along with the glucose response.

utopcell 1y ago

Here's a (Gemini) AI summary that seems to be capturing the main point that the article wants to convey. ``` This page summarizes a study about continuous glucose monitors (CGMs) and how individuals can have highly variable glucose responses even when eating the same meals. The study, which involved 30 participants without diabetes, found a weak-to-moderate correlation between glucose responses to identical meals, with about 80% of the variation attributed to within-participant differences or measurement error. The article notes that high glucose variability is linked to increased risk of death, greater hunger, and poorer mental health and sleep. While CGMs are beneficial for people with diabetes to prevent hypoglycemic episodes, this study suggests that developing personalized nutrition recommendations for glycemic control may be more complex than previously thought due to inconsistent individual responses. The authors emphasize the need for more reliable dietary assessment and a deeper understanding of the behavioral, dietary, and individual factors that influence glucose responses. ```

utopcell 1y ago

It would be unfortunate if this article were to discourage folks from trying CGMs out. I am not diabetic but have found a lot of value in using a Stelo CGM sensor. At minimum, it gives me awareness of my current state. I routinely check it before considering desserts for example. Also, I was shocked at the spikes I would get from some food. Maybe an "obvious in retrospect" feedback was drinking a bottle of (non-diet) Coke. It consistently gave me 50 unit spikes (mg/dL). Nothing came close to it, including large meals or meals + desserts. On the other hand, drinking diet coke had absolutely no impact, which was contrary to what I've read before (the body is confused and produces insulin). Another surprising observation is the effect of consuming Feta (a particular kind of Greek cheese) : no matter what else I may have eaten, a piece of feta always leads to a reduction of 10 to 20 points for at least half an hour after consuming it(!) I doubt this is generally true, which speaks to each body reacting differently.

esdott 1y ago

As a long time diabetic (t1d) with direct relatives also afflicted with this horrible disease, it’s frustrating that we often miss the key factors in insulin resistance and fail to see how they fit in. The level of serotonin and its interplay with our current level of immune response/inflammation in our body is the single best predictor of insulin resistance. That’s simply because every good thing you can do to lower resistance increases serotonin. Serotonin then decreases inflammation. When you exercise for a long period of time you are not only increasing your immediate availability of serotonin, you are also increasing your daily availability for serotonin. Obviously it’s a little more complicated but from a big picture standpoint, either something is increasing inflammation in you today and increasing your insulin resistance or (hopefully) the opposite is happening and serotonin is moving your insulin through your blood stream like a mag lev train. On a side note, I do love cgms.

sinuhe69 1y ago

What about the famous breakfast? One prevalent theory among nutritionists is that the breakfast has huge influence on the insulin responses during the day: a low carb/no sugar, high protein and fat breakfast will not spike your blood glucose level and therefore will lead to a more moderate response to meal intake during the day as opposite to a high carb breakfast. I think the study should control this variable as well.

Klaus_ 1y ago

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lytefm 1y ago

I've been working in this space for seven years, this isn't new. There have been big studies from the UK in 2020 [1] and Israel in 2015 [2] about this. Some of my learnings: - Don't start your day with a large amount carbs. Have some insulin in your blood before eating that big bowl of oatmeal. Or just go for some yougurt with nuts and seeds. - The classical order of a three course meal (salad first, then main dish, then dessert) is pretty good in terms of preventing glucose spikes. - Going for a walk after a meal is great for bringing glucose levels down. - Eat at least 2h before going to sleep. Having high glucose levels disrupts sleep. - Alcohol lowers the glucose response of a meal, but is still bad unfortunately. - Diet Coke works. No spike vs loads of sugar with a real coke. - Stress can spike glucose like crazy, e.g. being in an interview or during takeoff. - If you really want to know how you react to some food, keep the circumstances (time of day, sleep, physical activity, stress) similar. There's too much influence beyond just the meal. I bet that everyone who is wearing a premium smartwatch or an Oura ring now will be using a CGM now and then in the next years. [1]: https://pubmed.ncbi.nlm.nih.gov/32528151/ https://pubmed.ncbi.nlm.nih.gov/32528151/ [2]: https://pubmed.ncbi.nlm.nih.gov/26590418/ https://pubmed.ncbi.nlm.nih.gov/26590418/

kristel100 1y ago

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whycome 1y ago

I like the idea that the proliferation of LLMs become frameworks for understanding that can help advance a field or help curious thinkers come up with novel hypotheses. If the body is something like a trained model, it’s not crazy to think that it will respond to something like fake sugar (eg aspartame) with biological processes that would only be expected for real sugar.

turnsout 1y ago

Leaving aside the science, this paper draws the wrong conclusion. Just because many factors influence BG response does not mean CGMs are somehow invalid as a tool for personalized nutrition. Quite the opposite. A good nutritionist does not work in a vacuum. They know the holistic nature of BG and will tailor their recommendations to the patient based on lifestyle. (I worked on a holistic diabetes management platform)

jadeisokay 1y ago

i'm a type one diabetic. this is uh, not news to me. i can eat the same thing every single day at the same time and see different numbers after every meal. stress, hydration, heat/cold, fatigue, if the wind is blowing, so many other things affect blood sugar.

fcpk 1y ago

Sorry to complain, but what the hell is this horrible AI summary link? The actual study is not open, but surely enough something a bit more precise could be given.