I ❤️CARBS! (and so should you!)

This blurb may be informative on that.

Chasing with water, according to a dentist on here, apparently negates much or all of the dental risk.


Ok, question for you regarding fueling zone 1/2 60-90 minute sessions. Do you really think there is a huge difference if you fueled a 60 minute zone 2 ride with say 100 grams of carbs IF at the end of the day your totals were the same? I struggle with this concept and people generally like to say if you fuel the ride it helps with recovery and you won’t be as hungry after the ride etc. and then there are those who start fueling these easy rides and gain weight (obviously they didn’t adjust their total overall calorie consumption) that’s all good and everything but let’s just assume you are going to take in the same amount by the end of the day regardless of the fuel you consume during the ride. Is there any difference to recovery? There just doesn’t seem to be a need to push zone 2 rides to the point that fueling during is necessary and if you complete the ride and recover the same before your next ride is it really optimal to fuel them? I think that it is dependent on a few factors such as body composition and overall threshold (there has to be a difference between a lean 130lb male burning 700 calories in a 60 minute zone 2 ride and a 20+% bf person burning around 400 :man_shrugging:t3:).
So, if you were designing an optimal routine for someone who does not need to lose body fat, is at or near their race weight, and willing and able to track all macros throughout the day, would you have them max out fuel during all bike sessions and fill in the test with real food off the bike?

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Not really. Here are the recommendations from my book. Table of Intra-workout Carb Needs Per Hour of Training

Not for z1/2 <90min rides, probably not. Maybe very marginally out near 90min, hence the increasing recommendations in the above table as duration increases.

If by “push” you mean elevate the intensity sufficient to necessitate fueling, I agree.

Necessary ≠ Optimal, though.

If the Z2 ride is >90min, glycogen repletion is likely to be enhanced by fueling intra-workout to some degree.

Yes but there are probably competing factors working against such a discrepancy. Larger folks tend to burn ever so slightly more kcal per watt (barely), and less fit folks tend to burn much higher percentages of carbohydrate for their energy production.

Unless the person possessing 20% BF is pre-diabetic or type 2 diabetic, intra-carb consumption doesn’t need to be modulated (reduced from the tabular recommendations) simply because of body fat levels. Exception: if they’re legitimately doing <100W the entire time.

You’ll like my book. :slight_smile: I make ~$12 when you buy it. If it’s not worth that to you, I’ll paypal you the full price. Answer: if there’s a race coming up in the next couple months, I’d program somewhere between the recommended and maximum amounts, always. If no race, and satiety and life-enjoyment was primary goal, then maybe near minimums if personally preferable to the rider.

Good questions!


Thanks for the thorough response! Your contributions to this forum are priceless in my opinion. I am definitely comfortable supporting you financially and will purchase a copy of your book. Any chance you do a one time 60 minute consultation for a fee? I know you aren’t taking new coaching clients right now but there might be a market for you to have a video call or something where someone could bounce some ideas off you and come up with some personal recommendations. I know I’d be interested if that were a possibility.

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I bowed out of that a while back, unfortunately. Time-cost got too high. With TextExpander at my fingertips I can be lightning on my keyboard!

I’ll be starting a youtube series on https://www.youtube.com/channel/UCfQgsKhHjSyRLOp9mnffqVg for endurance sport performance “soon.” (couple months prob… maybe sooner)

Edit: thank you for the kind words!


Just to add, I’ve purchased the book and found it very useful (I’ve no affiliation with Alex/RP - other than being on the same forum).


I sometimes heard (and unfortunately let myself be influenced by) bro science things like

  • I want to increase fat metabolism and as soon as carbs are in the system fat metabolism gets decreased
  • in a similar way as: as soon as intensity rises into tempo/threshold range for too long, then metabolism will switch to carb preference and it will last very long until fat burning gets going again

Hard to get these conceptions out of the head because they seem so nice and simple.

Totally understand that! I agree. They are simple. And true too!

Wrote this yesterday actually, and fits nicely here. Apologies for length!

"Mechanism, therefore application" is the fastest way to folly in exercise and sport science.

It works better in limited-dimension systems, like engineering and physics. Not so much in infinitely multidimensional biological systems that have a nasty little thing called homeostasis to maintain. Negative feedback loops often shut down acute responses to anything, and totally negate and erase any potential gain that might theoretically exist if the acute effect were to continue indefinitely without interruption.

4 prominent examples that has gotten loads of folks in the sport science community caught with their feet in the mouths:

  1. Low-rest hypertrophy training causes a larger post-exercise testosterone and growth hormone increase, therefore it’s better or even essential for muscle growth. Truth : More inter-set rest is better >90% of the time.
  2. Post-workout carb:protein intake ratios like “4:1” results in higher circulating anabolic hormones, therefore bigger muscles or better recovery. Truth : Ratios don’t matter.
  3. Fasted training increases fat-burning during training, therefore it will result in more fat loss or weight loss chronically. Truth : There is no body composition or weight benefit chronically.
  4. Higher fat oxidation rates with high-fat low-carb chronic diet, therefore improved exercise performance. Truth : there is no benefit and may be harm to performance.

Pesky homeostatic mechanisms!


I just saw this and despite the importance of the question, I love how it is phrased and made me laugh. To be honest, this really sums up nutrition back and forth discussions - we all want someone to slap us to stop us from doing barmy things.

@Dr_Alex_Harrison thank you so far for the insights and for the useful metaphorical slap!


I’m going to back off 2:1 fuelling on TR workouts. My weight has been stable for years at ~70kg and used to regularly do turbo sessions fasted, but since drinking a bidon of 2:1 on each significant session it has gradually crept up, despite a significant increase in workload (e.g. SPB MV). And no, I don’t think it’s all muscle.

As a result, on the road, the FTP increases are being negated by the increased weight on hilly rides.

I’m going to experiment with electrolyte rather than carb hydration for a while and see what happens (or maybe just reduce the carb concentration).

Would you not back off something else in the day? I guess it depends on how much of 2:1 mix you’re having - I go for a 40g/ 500ml bottle which my mix works out at 160cals.

I do sometimes just have food that I would have later in the day, during the workout, so it’s not necessarily “extra”. Doesn’t work as well on intense workouts though.

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I go once a week in the dishwasher, then try to remember to through the lids in baby bottle sterilising fluid once a month.

Not to stoke a fire, but thoughts on this? Sweet Little Lies - Sugar and Cycling and Sports Drinks @Dr_Alex_Harrison

garbage bro science. Doesn’t even differentiate between insulin response during exercise and at rest


I was hoping you’d say that! :smile:

I think I’ll be relying on @redlude97 for my concise summaries from now on. Spot on.

I don’t possess the conciseness gene.


Do this for easiest rides.

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I got the IDGAF gene since this isn’t my area of research I’m not pissing in my own swimming pool

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it’s hard not to do that when you specialise - at least during my PhD I had no energy to give a toss about other areas for a while at least. Would imagine for this realm of science to be even worse.

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I tried 700ml + 100g sugar + 1 lemon, way too sweet. Today I tried a 70:30 sugar:maltodextrin ratio and that was quite nice.
I also used @Nate_Pearson’s suggestion of pre-diluting the carbs in warm water. That worked so much better than just mixing cold water with the carbs. The drink doesn’t contain any clumps which helped make the bottles easier to clean post ride.
Really happy that I have a cheap and effective way to fuel on the bike :+1:t2: