Carbs At 90g Per Hour And Blood Sugar Crash

This week’s episode from FastTalk is very insightful on this topic!


This may be overly simplistic summary. Yes the human body has a ton of available energy on board, but the conversion of those energy sources to usable fuel is a different story. Lord knows I’ve got enough fat stores to provide energy source, but doing SST my body cannot convert it fast enough.

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Buying your own blood glucose monitor can be insightful. They’re like $20 or $30 and usually include 20-ish test strips to get started… cheaper than any doctors appointment or bloodwork. Get a couple baseline. Check some 2hr-after-meals, and some before+after readings on your bike rides.

I wish there was a similar test for insulin, but my bet is you’re slamming so much carbs on the bike you end up with a ton of extra circulating insulin. When you get done, it’s still pushing glucose away for storage, but with no more inbound carbs. At rest the body should be mostly burning fat (RQ of 70), but it turns out insulin inhibits fat metabolism, so actually your body is making you hungry because you’re experiencing an energy crisis.

You might try stopping in-ride carbs 30+ minutes before the ride is over.


This for the win.

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I haven’t done the same experimentation, but I would agree it’s a bit simplistic to say the Pro’s just eat those products. Sandwiches, rice cakes, made up bars - people have done books on the recipes of what’s prepared!

Even when it comes to recovery - there was BBC documentary following Thomas/ Sky on the 2019 tour - he was basically giving out about being handed boxes of rice and chicken, and having to force himself to eat them. I’m sure he necked a recovery shake, but it wasn’t what they were using exclusively.

Personally, I struggle (as discussed on the last podcast) with the whole weight control v fuelling. Banana’s and dried fruit (dates/ raisins/ cranberries) seem to sit better with me mentally than using carb mix, although I plan to incorporate the carb mix back in when I get to build. I use carb mix outside, as it’s obviously easier to get it in on hard spins.

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I think the context is important.

Your comment which i quoted responded to a string of posts where we were discussing available on board glycogen stores available first thing in the morning for workouts. Essentially fasted.

We were not talking about doing an ironman or other workouts after proper pre-race/workout fueling. No one is disagreeing with that point.

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Apparently you then missed some of my initial comments because because I was responding to OPs post and the experiences he made with the excessive carb intake.

Also you are messing up the terms. Getting on the bike in the morning does not equal fasted training. When you get out of bed your glycogen stores are full (if you had a normal dinner).

For what it’s worth my examples just highlighted that an one to two hour workout worth 1,000 to 2,000 kcal is possible without 100g of carbs per hour. (What causes OP problems).

Again, for what it’s worth, I never advised anybody to fuel a certain way. For further context see my initial comment and the question of OP.

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Take a listen to that FastTalk episode 37 linked above. I am by no means a scientist, and will not even try to do it justice by repeating the argument they make. But my takeaway was that he made a strong case for why the body shuts down insulin response during workouts, and for about 1 hour after. So taking in carbohydrates while working out hard, that you more than consume in terms of energy shouldn’t be a problem.

Did you even read the post of OP? Obviously, it is a problem for him/her. :zipper_mouth_face:

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I did. But given this fueling strategy is so common. There might be other causes for that? Maybe getting in a recovery shake with a good protein & carbohydrate mix immediately after the ride would solve it?


Will definitely give it a listen. I agree insulin secretion to food should be lower in exercise, but that doesn’t mean it always is. And reduced isn’t the same as none. A huge portion of the population has an unhealthy insulin dynamic already (and don’t know it; see anything on Kraft test), so something could easily be going wrong for the OP.

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