A case for 120/g hr....and Gut Training

https://glut4science.com/publicaciones/entrenamiento-nutricional/120-grams-carbohydrates-per-hour-during-exercise-improve-recovery/100

a case against it… https://www.frontiersin.org/articles/10.3389/fphys.2023.1150265/full

It’s good to read contrasting research.

Here is another one from Frontier in favor of LCHF diets, but this was done on short, high intensity efforts, not a 3-5 hour ride.
https://www.frontiersin.org/articles/10.3389/fnut.2023.1084021/full

The one you noted was on 6 x 800 meter running intervals, not hours-long rides, but there may be research on LCHF for long endurance rides, too. And the LCHF in the context of pre-exericise diets, not while riding/running, so it is not an apple to apples comparison.

Which does not mean that LCHF is not the best everyday diet, Trevor and Dr. Iñigo were discussing eating sensibly between workouts, not loading up on carbs habitually. The research I brought up, and I am not an expert on this, is specific to carbs during exercise, not a high carb lifestyle diet.

That’s an amazing study. Thanks for forwarding. 31 days of high or low carb diets, calorie balanced, and monitored using CGMs. WOW! Love how it busts the myth that you need high carbs for high intensity intensity performance. Both diets worked deliver 1 mile running performance (~6 min all out). Even a trend for fat group going faster.

But yes, to your point, you’re interested in the consumption of 120g/h of carbs over 3-5 h rides and how that can be achieved using multiple transportable carbohydrates (fructose/glucose blends). While this certainly can be accomplished, in my experience this high rate can also contribute to GI issues (gas, bloating due to the required fermentation process for digestion), especially in the older athlete.

Regardless, probably never hurts to experiment with both approaches and see which one suits you best… we are all individuals, and we learn best from reflecting on our own experiences.

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A few questions

  1. Why was the LCHF group given advised sodium that the HCLF was not?
  2. The study repeatedly states “Iso-caloric” - what was the actual caloric intake of participants?
  3. Training load is in a unit-less value (RPE x Duration) - What was the actual duration and intensity?
    3a. Was duration and intensity controlled or guided between groups? Did one group do all low intensity and the other all high?
    3b. which RPE scale was used? - If 6 to 20, then assuming an RPE of 15 - a Weekly TRIMP of ~2500 = a duration of 166 minutes per week or 27 minutes per day.

I could go on, but the obscurification of information guides us to believing a narrative. This research was well designed to prove that LCHF does not negative affect high-intensity performance but it lacks the control, data, and efficacy to do that. (In my opinion)

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I hope this turns into a long thread! Fascinating conversation!

I’m looking forward to reading that study. Rob raises some interesting questions about it. Will be nice to get into the details and see how it holds up.

My only response right now is to take a bit of a different angle that I believe strongly in. I think it’s a mistake in general to purely talk about LCHF diets and HCLF diets. We are too focused on the macronutrient ratios and not on the quality or the nutrient density of the foods we eat. For example a LCHF diet includes both people who eat a lot of avocados and salmon and conversely people who eat a stick of butter every day. Those are very different diets yet they both can fit under LCHF.

I have no particular issue with eating carbohydrates - what I’m concerned more about is the sources of those carbohydrates. I eat plenty of carbs but I get them through fruits and vegetables. My concern with HCLF diets is that they generally require the consumption of a lot of free sugars. The scientific evidence for the negative health impacts of free sugars is, in my opinion, overwhelming. I will personally consume them during hard workouts or in races, but that’s about it. The rest of the time I focus on getting my carbohydrates through healthier sources. At the end of the day I don’t really care if my diet is labeled as HCLF or LCHF.

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I’ll keep this one going.
@robpickels The control was pretty good IMO. These are not easy studies to do.

  1. Sodium intake is the primary remedy used to alleviate the ‘keto-flu’ symptoms commonly associated with hypoinsulinemia. When individuals consuming a standard diet reduce carbohydrate content and replace these calories with fat, blood glucose is lowered and insulin naturally falls. When insulin levels are low, the kidneys excrete more sodium, and less is reabsorbed back into the bloodstream. In addition, low-carbohydrate diets tend to stimulate the release of hormones, such as glucagon and cortisol, that can increase sodium excretion. These hormones can also cause the kidneys to release more water, further contributing to sodium loss (lots of water weight lost during LCHF treatment; Table 3).
  2. Table 1, Row 1, about 2500 kcal/d each
  3. sRPE uses the 0-10 scale which is valid and used throughout the literature and in practice (we use this in Athletica.ai to back up our internal/external load markers). These are well trained middle aged runners so they aren’t likely to do anything other than what they normally do in their typical weekly training, and the monitoring confirmed this (Table 2).