This is the point. Exercise effectively inhibits insulin release from the pancreas because muscle contraction causes translocation of the GLUT4 channel to the myocyte membrane, allowing for glucose uptake into the myocyte without insulin stimulation. This is why patients with type 1 diabetes need to decrease their insulin dosage (if they’re on basal-bolus and eating; if on a pump, reducing basal rate) before exercising to avoid hypoglycemia.
Tim Noakes is horribly compromised on this topic.
I agree that we need to think about our health.
The biggest problem most of us face is the western diet with its copious amounts of calories, sugar, processed oils, and lack of nutrition.
Carbs come in different forms - nobody got diabetes eating broccoli and spinach 5 times per day.
There are indigenous tribes that get near 100% of their calories from carbohydrates but they have little to no diabetes, cancer, or heart disease. These people also live in a lifelong chronic calorie deficit. They aren’t eating bread and sugar as their carb.
I’m sure we could find similar examples of peoples that mostly eat meat and do not have the usual ailments.
Whenever these tribes add flour, sugar, and fast food to their diets they gain weight and eventually start coming down with all the usual western diseases.
So armed with this kind of knowledge one could switch to a diet of quality proteins, vegetables, some legumes, and a few whole grains. But most people aren’t willing to give up the convenience of packaged food, pizza or burgers on the weekend, or the constant drip of soda like an IV. Lots of people eat almost every meal out or pre-packaged. It’s no wonder why type 2 diabetes has been on the rise for decades.
This hits squarely I believe. @stevemz sitting for hours @230W is bound to respond very differently to sugars than the couch potato watching Netflix all day. At least that’s what I’d expect (bro science alert 
). Similarly, the protein levels a gym bro consumes are going to wreak havoc on the body of said couch potato:slightly_smiling_face:
Just n=1 if anyone is interested, here is my blood glucose reaction to a few short efforts:
Fuelled with 120gr of carbs = 480kCal (60gr maltodextrin, 60gr fructose), spread evenly across the efforts…
Zoomed out a bit from sleeping levels to end of day
I had a family day in the afternoon involving induging in waffles drowned in honey, cider, and cookies this afternoon hence the unusual peaks🥳
The blue line is 90mg/dL
You mean just after eating 800kCal of breakfast:yum:? Yeah, I’m not too worried about that 
That’s the night before for context. Woke up at 7:00, had a gigantic bowl of muesli with a huge cup of coffee at 7:45 
Pretty sure I ate more than 5000kCal today, actually, which should put me at about 1000kCal excess. That‘s totally fine for a splurging day. I burn 2000-2500 kCal per day 5 days a week on top of my 2800 kCal base rate (I‘m not a climber). I‘m not going to cut that on an easy day like today, not with my weight still about 2kg below long term baseline🙂
Yeah, indeed 
Didn’t take the time to tinker with CGM when I was setting up for the races 
Interesting to see those charts, thanks for sharing. Does the blood glucose level during exercise mean anything? It seems to be very high when you’re taking your workout sugars.
Yeah, I’m too quite sure about that yet.
The pattern I’ve seen so far:
With my normal fuelling (60gr/h spread out every 10minutes) for my typical 2.5h workout at 6:00, I see:
I’ve experimented recently with a “megadose” of 60gr before leaving the door, then top up at a rate of 120gr/h. The result was:
Interestingly, I had been observing for a while already that my intervals got markedly easier in the second hour, which I have never experienced in previous years. That’s the opposite of what I expect (normally I struggled with the later intervals, the last ones should be the hardest right?). I now think that is linked to the through I saw in blood sugars early on with my normal fueling regime (60gr/h), and that that didn’t occur in previous years partly because I trained in the afternoon (so starting fully topped up).
More experimentation is required! But what is already clear to me (n=1) is that sustained blood sugar at 160 or more during workouts all but guarantees a ridiculously low RPE, and that blood sugar returns to baseline fairly quickly after a workout.
This probably makes your question worse rather than answering it but I can say for sure if I do a vo2max workout with 6x3min at $hard % my blood glucose goes through the roof without eating anything at all. I have to eat like a moron to get close to 200 from food but I can get over that with really really hard efforts even 16 hours fasted.
Something like this makes sense. Body shifting around what it’s already got (plus whatever you’re giving it). Very interesting stuff
@dmalanda do you wear a continuous glucose monitor? How did you get that data. Are you diabetic or just a curious person? Lol just wondering
Yeah, it is hepatic glucose for sure. I was more pointing out that for my N=1 it was a way bigger contribution than I expected it to be before i started wearing cgm and it makes the intra workout nutrition data quite a bit less clear.
Yeah, I noticed that too. The spike occurs with or without fueling. It’s not only VO2max either, even a dead-chill walk just after waking will spike me into the 140s while still fasting…
However, I know for a fact I could never sustain 200 mg/dL for the full duration of Spanish Needle+3 (2h) after a 16h fast and without fueling.
On top of that, the last intervals would never feel so manageable as to make me decide to tack on another hour of Spanish needle @500W, just for fun
For me that was totally unimaginable before I started the carb experiments…
Just a curious person, I’ve been struggling to fuel my rides for a while (it gets really hard for me once I reach 1000kCal/h burn rate).
I started experimenting with Supersapiens 3 weeks ago, and will probably keep tinkering with it until I understand my body’s handling of blood glucose better…
Interesting idea 
I wonder if I could estimate my endogenous stores by starting “topped up” and riding myself into a bonk at sweet spot for example (should not take more than a couple of hours from experience). I think the variable I’d be missing is total blood volume…
And maybe it’s even possible to guess the fat oxidation rate as the energy not coming from carbs in that ride…
More experimenting ahead!
My recollection is that Nate (and some of the other hitters, like Keegan Swenson) only does this in the window leading into a long race like Leadville, or during a stage race.
I wish they had made this point clear on the podcasts. Well said!
Very interesting thread here… I have a strong familial history of T2D. I’ve been quite concerned about fueling when cycling and typically only have gels when I train or cycle.
I do note significant blood sugar spikes but these come down within 30 mins of intense exercise.
From what folks have posted here, I don’t have much to worry about. My last HBA1C was at the top end of normal (I have confirmed impaired fasting glycaemia).
I rode a long event yesterday 120mi / 10.8k climbing. Took me about 7 hours, I fueled with 6x80g Beta Fuel + 2 Clif bars + 3 Maurten 100 + 2 bags Clif Bloks, in 7 bidons of water. I ate a PBJ sandwich for breakfast with coffee at 4:30am. Event started 6:45am and I finished around 2pm.
I found myself in an extreme sugar high for hours after the event. Around 7pm it was uncomfortable. I craved veggies and avocado even though my wife had made lasagna.
I’m now wondering if I should have continued to ride to clear the sugar high.
Very interesting 
In what form is the 120g/h?
Yeah they should caveat it a bit, especially the large human Nate (@stevemz that really made me laugh!)
Just revisited this thread as a result of a comment above. I am that person and up until now haven’t been consuming anything like 60g/hour except on long hard group rides. However I looked at an old 2018 metabolic test I had done and discovered that at my endurance power my efficiency was WAY down at 18% and only got to to 20+% on supra threshold wattages. This despite have a presumably reasonable FATMAX of 0.75=-0.80 g/min at those power levels. Doing some maths has shown that this makes a massive difference to how much more CHO I should consume on a ride. I’m going to up my intake and see if it improves not only my performance but also my recovery which seems to have gotten worse over the last year to or so.
