I've finally got a working Continuous Glucose Monitor, and the results are not what I expected.
I installed it on Friday night and started it late Saturday night.
I finished dinner about 10pm on Saturday night, low carb, high fat with wine of unknown carbs and didn't have anything except black coffee and one flat white until about 22 hours later. I went for a solo 60km cycle that took about 6 hours elapsed, but only about 3 hours moving time; caught up with friends so had a couple of longish coffee breaks.
My fasting glucose is higher than I hoped - in fact, in a high enough range that I might get diagnosed with pre-diabetes. The NHS no longer uses fasting glucose, so phew!
I had thought that my plans for the day would drop my glucose, but instead as soon as I started pedalling, it climbed towards hyperglycemia! 😱 I was really worried about it, repeatedly checking the level with my phone to make sure. But coincidentally I was listening to a Diet Doctor podcast, and Dave Feldman was talking about his lean mass hyper-responders and said "their CGMs are flat as a pond, except when it shoots up with exercise". So I am somewhat normal - at least for his abnormal group.
Not quite sure what the cause of it going up is. Lactic acid (which your muscles produce when you exercise) is converted to glucose in the liver. Exercise can trigger glucagon which drives gluconeogenesis, also producing glucose. If my muscles are fat adapted, maybe they just didn't use the glucose, thus keeping it elevated. Do I need a ketone metre to confirm I am fat adapted? 😕 I also wonder if I would fail an oral glucose tolerance test, if my muscles aren't using glucose. But the glucose dropped when I stopped and settled down quickly after the ride, so maybe I would be OK. 🤞
Food doesn't seem to change my blood glucose measurably. My high fat dinner didn't move the needle
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Subtle_badger
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Oh good for you, I'd love to have a cgm and take note of everything I ate and how that affected my glucose . Yes, apparently the exercise has a major effect on glucose and the fact that it came down quickly after resting, I wouldn't be overly concerned .I love Dave Feldman, he's great, all the experiments and tests he does on himself.
Yes, I am in Australia. Thanks for the link, sounds like a really good offer. I'll look into that properly in a few week's time. My life is a bit topsy-turvy with my son being home and travel plans right now.
I think it is totally normal for your glucose to shoot up with exercise. My ketone levels always go down after exercise, and that's despite the fact that I eat strictly and otherwise maintain high ketone levels.
My exercise trainer once explained it this way: if you think about it, exercise always temporarily WORSENS the levels of the things in your body that it ultimately IMPROVES, like pulse, blood pressure, stress hormones...and blood sugar.
I don't think that's a very scientific explanation, but it seems to fit.
🤔 Apparently not everyone's blood glucose shoots up with exercise, though. Diabetics are told to take a brisk walk after a higher carb meal. The muscles burn their glycogen so the blood glucose replaces it.
But it's common enough in keto, though. I speculated it's because
I don't think there is any mystery about those "bad" things going up while exercising - it's during periods of exertion that they are meant to go up,to help our body meet the demands we are placing on it. They are good in that context, only becoming unhealthy when they continue all the time under chronic stress.
There is not much difference between semi and full fat milk, in terms of carbs. To prove it, I had a proper flat white yesterday, and it caused exactly the same response.
I'm always frustrated trying to find coffee places that offer "no/low sugar" milk options. Usually there's oat or soy, which too high carbs for me, and when they offer almond milk it is the one with carbs, not the 'no sugar' version. You'd think there would be enough people asking for low/no sugar milk that it would become more of a 'thing'. Short rant over! -- glad to hear you've been able to get on with your CGM experiment. It's interesting to follow. Hopefully it will be insightful for you. -- I had a quick read of the Freestyle Libra website and was interested to see how the readings are taken. I had thought the arm monitor had a little pin-prick needle in it!! Didn't realise it takes readings from fluid under the skin. Silly me. -- I saw them advertising the other day and am considering giving it a go. Knowledge is power, surely it can only help to understand more about how our bodies respond.Keep posting updates if you can. Really interested to hear how you get on!
Thanks for the support. It's an interesting experiment for sure.
I find it amusing to order a coffee with full fat milk while everyone around me is asking for semi or skimmed - and they are all overweight, and I am not.
At Pret à Manger (where they have a £20/month subscription), they have semi and skim cow milk, sweetened soy milk ("apple concentrate" 🙄), rice-coconut milk (sugar), oat milk (sugar + rapeseed). But also they have cream and of course Americano. So I have options.
The first time I applied a monitor, I had to talk talk myself into it, the filament looks formidable and painful, and I couldn't touch it or I might contaminate it. But it is truly painless, and easy to do. Pulling it off is worse, but only because of the strong adhesive.
Ah, ok, so I'm not too silly after all. It does have filament. That makes more sense. -- I've just tried to take advantage of a 2 week trial, but unfortunately my phone is not compatible. -- yes, perhaps I should ask after cream. I generally end up ordering black coffee, which is fine if its a good tasting blend. Yeah, the 'fats' conversation is one I dread. There is a limit to how many times I can bang my head against a brick wall. I still try, but I'm not so evangelical about the whole LCHF business now because often people just don't want to hear (even when they ask!) and it seems to somehow make them even more entrenched in their opposing views. Intensely frustrating to see some people doing the opposite of what would truly be beneficial for their health. We can only hope that changes in public information and health services start happening soon.
Yes, the fats conversation used to happen a lot at the yoghurt section in the supermarket. I made a mistake this week and bought 0% fat super thick yoghurt (I generally make my own) so I’ve been adding some double cream to the daily portions.
Oh great, you have cream as an option... that would be my choice for sure. Every time I go grocery shopping and I have 8 cartons of cream, the checkout woman will ask me what am I cooking? It stumps them when I reply that "it's for our coffees"... they don't know what to say 😁
I haven't eaten for the last 24 hours, just black coffee, water and lo-salt. Glucose has remained in the 6-8 mmol/l range (spiking even higher) for most of the time. I am seriously wondering if I am in ketosis at all, or am I just living off gluconeogenesis.
I will do a proper fast over the weekend, and see what I can learn.
It's a freestyle libre. Yes, you can buy it in the UK without prescription. I think you can even get it from boots, but you can order it from the company.
I do occasionally (3-4 times a year) eat rice based sushi as I really really love it. On a more regular basis I stick with just the sashimi grade fish. Sashimi grade fish is much cheaper from the fish monger than a sushi restaurant - I've found I can eat a lot of it just with some seaweed salad or some HM wasabi mayo.
I was hungrier than usual this morning, but my blood glucose was rising at the time, so it's a mystery.
The sushi was via the TooGoodToGo app - a magic bag, so I didn't know what I would get. As well as the sushi there was a sandwich. I was going to bin it, but apparently it's a chicken katsu sandwich they charge more than £10 for 🤯. I think I will try it.
It's great, if you like carbs! Mostly the things are leftover pastries and sandwiches from cafes.
I was walking home from the cinema (Candyman didn't raise my blood glucose; I was unaffected by the stress and the candy 🍬 🤭) and I remembered the sushi place used the app. I opened the app and found they had bags available in 1 minute! After peering in the bag of a stranger, decided to order one. I paid £5.50 for about £24 worth of food! it wasn't as good as freshly made, it was presumably leftovers made for dinner time so 4-6 hours old.
Woah!.. do you think it was as a result of the bread, or the contents?.. or just the whole combination? Even though there is a clear reaction , your body seemed to have coped well with your levels adjusting again quite quickly, or maybe I'm misunderstanding how it works! Did you feel unwell at all?
Doctor Google tells me that glucose levels should go back to normal (7.7mmol/l) within 2 hours after eating a meal with at least 75g of carbs. My meal would not have had much more than 40g, and at the two hour mark I was at 8.1 - though I just remembered CGMs lag blood sugar by 20 minutes or so, so maybe I squeaked in under the wire. I was down to 6.1 by the 2 1/2 hour mark.
The bread is probably milk bread, so has a bit of sugar, but still, less than 20g carbs per slice. Not much other carbs there, except for the chicken breading and the handful of grated carrot.
It has settled down and stayed down. I skipped dinner last night (wasn't hungry), and feel fine this morning.
The sandwich and the pizza are much the same, with glucose rising sharply and then dropping back to normal within 2 1/2 hours and then remaining steady overnight and into the next day. The sandwich was much higher than the pizza, I expect the fat buffered the release of sugar into my blood. That really makes the idea of low fat spread on your bread a bad idea, at least for me.
The sushi is a different story. It's even hard to work out how many carbs it has - being insulin dependent must be a nightmare! But according to what I read, your blood sugar should settle down again with two hours, but mine stayed elevated over night and was swinging about for the rest of the day.
It's worth noting that the pizza and sandwich were eaten mid afternoon, and the sushi at 11pm. It's not quite a level playing field, but I still know I will never have another sushi meal again, because the response was so extreme.
NB: this is not advice for anyone else. This is how my body responds, you may be quite different.
Someone said honey is better for you than sugar. I thought I would test this, but I only had a couple of hours left.
So I did a simple test. Ate enough syrup to give me 15g of sugar. When it settled down again (about 90 minutes), I did the same with honey. Results were identical, and honey has more fructose, which doesn't raise BG, instead going straight to the liver.
For me, sugar is better for me metabolically than honey. It may have other benefits, but they do not outweigh the harm to me. I will continue to abstain from both.
Graph showing identical glucose rise for syrup and honey.
It looks like a tiny smoke detector with a needle.
What are your main take-aways from your experiment in summary? Do you think it was worth the fuss?
I have enjoyed looking at your infographics. You have some IT skills! I'm envious. A few months ago I learned to merge two photos and that took me about a hour to work out!
My best attempt at an infographic was this graph illustrating the effect of the covid vaccine on my daily average resting heart rate. Somebody replied to this saying they didn't realise that one of the effects of the vaccine was a deterioration in handwriting and IT skills.... 😳
Thank you for the graphic. I really laughed hard at it. Like actual LOL. People stared at me. But it's interesting data, but unsurprising now I reflect on it. After a vaccine, your body thinks it is sick, and raised HR is one sign of infection.
You are going to hate me more. I did them all the graphics on my phone!
I think the experiment was worth it. I think the insights will keep coming over the next few weeks, so I am glad I recorded my experience here so I can come back to see as I learn more.
My fasting glucose is rarely below 5.5 even in the morning and sometimes higher than 7. But it stays in that range all the time, and even the sushi didn't get it higher than 11.1. It actually drops with my So if I get a glucose test, I won't be worried about the results, because I know I am different.
I think most keto people have a low glucose level than me (watched a video where a guys is normally at 80 ==4.4), but it's not a competition. Mine is normal for me, and in the healthy range. I think my hba1c will be higher than I was expecting, pretty close to what it was in 2016. But again, it's not a competition, and whatever number I get, I will know it's not hiding a rolling set of hyper and hypo glycaemias.
I have also learnt that blood glucose and hunger are completely unconnected for me - which is very strange.
See, I am having more insights as I type this. Very worthwhile, for me at least.
I'm still eagerly anticipating the arrival of a smart watch with a non-invasive blood glucose monitor. I quite like having my basic health data on hand to make sense of. I use most of the health functions available to me on my watch and phone and I often look at the little graphs. There was a rumour about apple watch 7 having a glucose monitor but it's not going to happen. Maybe next year.....
GI and thus GL are calculated by literally sampling the blood of (google google) 10 people, and averaging them. That makes it a very useful tool for guessing how an individual will respond to various foods, but that is the point of my experiment; I don't have to guess anymore - at least for the foods the foods I have tried. My body responds to semi-skim and full fat milk in very similar way, so I will only have it as a treat.
My theory is that my muscles aren't interested in glucose, so I guess that suggests my muscles are insulin resistant.
I no longer think I have raise BG overnight. When I was searching for something unrelated to CGMs, I found this healthunlocked.com/lchf-die... and Dr Unwin's pre-breakfast BG is in the same range as mine.
The app also gives you an estimated Hba1c, which is 34 in my case, so now well below the threshold for pre-diabetes. I may not handle glucose well - the jury is out on that subject - but as I rarely eat any, that's really not a problem.
Still learning, though, and I really appreciate the feed back.
Dietdoctor's Dr Brett mentioned the blood glucose raise in today's YouTube post. Mine would easily be my biggest high of the day, excluding all the carbs, that I don't normally eat.
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Interesting thing I noticed!