Am I Over fueling?

You might be right and certainly have more knowledge than I do. My experience was that I didn’t really need to fuel at all until my weekly training hours tipped past 10 hours per week or in individual sessions past three hours. Caveat: I was also relatively young and had years of endurance training through high school and into college.

Definitely an N=1, not backed up by any science or even solid coaching recommendations.

I’ve only been training for 6 years, and haven’t had a lot of fueling issues. Here is my base for this season:

  • averaged 8.3 hours/week from first week of October 2021 thru end of January 2022
  • lost 20 pounds during that time
  • winning in the kitchen when not on the bike
  • randomly pulled up some workouts in January and see a lot of mid-week rides burning 1000-1500kJ and only ate 200 kcals on the bike (a couple fig bars), HOWEVER post-ride had quick snack (chocolate milk) and then dinner within an hour
  • weekend rides I generally see things like burned 1800kJ and consumed 700kcal or roughly 40%

So that worked fine, but I was really certain to be winning in the kitchen when not on the bike. Based on some experiments (where I intentionally bonked) I seem to be a pretty decent fat burner.

Now I’m going to try going the other direction:

did my first 90g / 28oz bottle on Sunday and no issues. Going to take some minor adjustments to what I do off the bike, the other 160 hours/week (assuming 8 hours on the bike). Will try it for 3 months and see how it goes.

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Yeah this helps tremendously. The more type 1 fibers you’ve got and the more efficient your whole “engine” the better your body will manage with lower exogenous carbs.

Full disclosure: I’m certain I’m personally biased in the opposite direction of you because I had years of strength/power/speed sport experience before coming to endurance sport.

I was hypoglycemic most of my first century ride while intaking 117g/hr, (plus some cookies) back in 2018.

Lots of large inefficient fast twitch fibers and disastrously low CV capacity made my body operate a bit like driving a top fuel dragster around down in first gear. :slight_smile:

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Which part?

When a person has metabolic syndrome, which usually (always?) includes type 2 diabetes, or some level of blood sugar dysregulation, absolutely there should be caution exercised not to overdose carbs during training. But yes, dosing carbs sufficiently high to prevent hypoglycemia, at whatever pace they choose to exercise, is probably wise.

2 reasons:

  1. Hypoglycemia drives hunger up, much longer than the duration of the actual low blood sugar. This often results in overconsumption later, above what’s needed for kcal balance.
  2. In both T2D & T1D, the muscle cells behave sufficiently differently during exercise, as compared to resting state, that there is substantially reduced risk of both hyperglycemia and further damage to pancreas if it’s T2D. I’d posit that during exercise one would be hard pressed to cause damage to a T2D pancreas by fueling with carbs, because the way a pancreas damages itself is by overproduction of insulin. Insulin production during any level of exercise is blunted substantially because muscle cell receptivity to glucose in response to circulating insulin is 50-100x greater than in a resting state.

But yes, this is a great plan of action.

That’s not quite true. Fat burned over the course of days, weeks, and months, is completely unrelated to the magnitude of fat burned during exercise, and much more closely linked to kcal balance (deficit).

If a person burns more fat during exercise, there is zero advantage, in terms of chronic fat loss, as an adaptation to that exercise. There certainly may be metabolic advantages for the person with T2D! But no differences in fat loss over time are present, simply because of greater fat burn during training.

The reason why: homeostasis is a pesky one. If you burn more fat in training, your body will find a way to replace it, if you’ve got the kcals onboard to do it. If you burn less fat in training, but are in a kcal deficit round the clock, your body will burn fat at a greater rate while not training, than if you’d restricted carbs during training. Bodies just like to go back to the way they were.

I’ve not seen this episode (or any of them). But I am familiar with the fructose absorption adaptive capacity of the gut, even in adults.

To my knowledge, as of yet, there is little research on the effects of gut training on long-term satiety. I imagine the research in the area of childhood-based increased fructose absorptive capacity points to satiety differences leading former high-fructose consumers to be more likely to overconsume fructose and kcal in general, as adults. (and thereby struggle with weight loss).

That said, without reviewing the articles they’re citing, I won’t say I’m 100% convinced there is a strong causative link there between high youth fructose consumption and difficulty with weight loss as adults.

One potential giant caveat in that causality link is the fact that the gut tends to adapt relatively quickly to new stimuli. A substantial reduction in fructose usage in training and outside of training for example, (or complete elimination) could harm fructose absorption ability during exercise within a week or two, I believe. I think maybe less, but can’t recall for sure.

That said, the longer a person does a thing, the more likely the adaptations to that thing are to become permanent. 20 years of high fructose consumption could plausibly lead to some very lasting adaptatoins for faster/greater fructose absorption.

Got a link handy? To the episode or the study(ies)?

If I had to guess, there’s going to be some evidence that “gut training,” especially with high fructose, can cause slightly reduced satiety around the clock, outside of training, because of the gut’s now-increased rate of fructose absorption.

I have no evidence that rate of absorption changes at low rates of consumption of fructose, or that it’s exclusively the absorption rate ceiling that is affected, which would only apply to cases of very high fructose ingestion rates.

I have no evidence in either direction, but if it ends up functioning like most of the rest of physiology (murky, on a continuum) then I’d bet that yes, gut-training for endurance sports may affect fructose absorption rates at rest.

That could be problematic for someone who already struggles to stay in kcal balance (maintain weight) with comfortable satiety levels.

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I’m very interested in how this works out - please keep us posted!

And @Dr_Alex_Harrison, for those of us coming from a high-intensity athletics background (for me, ice hockey and skiing) with a history of high sugar consumption, is there anything we can do during our training (especially base, which is coming up for those of us in the northern hemisphere) to improve our fat burning capabilities at low intensity?

I’ve considered a fully polarized training plan for base rather than SS, thinking that might help. I’m also open to changing the way I fuel during workouts, or changing my off the bike nutrition.

Open to recommendations - thanks in advance for your continued contributions here!

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Hmm… I hadn’t considered this. Let me think on it.

Okay… so here’s where it probably breaks down. There is pretty robust evidence that if a study holds protein intake and kcal intake the same, there can be substantial manipulations of fat or carb consumption, with no overall effect on body composition change. If anything, a higher-carb diet probably very slightly wins out for body composition change. But essentially they’re equivalent.

Timing of those consumptions also tends not to matter. (ie. 2 meals per day or 7 meals per day). So long as kcal expenditure and intake are matched between groups, and protein intake is matched between groups, it takes enormous differences in carb vs. fat approaches or dietary timing shifts to cause any difference in body composition over time. This holds true for periods of kcal balance and

Now, many things change in T2D and T1D. Going high-carb when T2D and relatively sedentary is probably a recipe for disaster. But for folks who don’t have current blood sugar dysregulation, high carb or high fat, probably has no real outcome differences on body composition. There will be differences in training performance, favoring higher carb, or equivocality, depending on study design. (always assuming same kcal and same protein intake between groups).

I posit that this is a sign of likely advantaged performance and that what feels bad, is actually just his body signaling “if you eat more carbs, I’ll give you a better threshold and VO2max performance!” … in very scientific terms.

I remain unconvinced that this is advantageous. This is just the kind of protocol I’d love to exploit. I don’t think it does anything other than make you psychologically more resistant to neurogenic hypoglycemia, maybe physiologically more resistant to hypoglycemia too, but importantly never by a greater magnitude than you are sacrificing max exogenous carb absorption and oxidation ability. That is, what you gain in fat burning ability is often outweighed by loss of carb-burning ability.

Hmmm… gout with SIS seems interesting to me. Do you mean SIS beta fuel? Beta fuel 1 or 2.0? If not beta fuel, I’m surprised SIS would be the trigger for gout if it’s indeed fructose-triggered, because SIS is relatively low fructose. Problematically low, for a lot of folks, actually! They use a 4:1 glucose fructose ratio in SIS GO Electrolyte which is their primary fueling-oriented powdered mix. Typically folks end up having substantial GI distress from overdosing glucose with that product, long before fructose causes an issue.

I am nowhere near SME re: gout. FYI!

This comment from @timpodlogar paired with my general skepticism has me wondering if I 100% trust all the uric acid claims Attia makes.

I don’t know what exactly Peter Attia says, but I have noticed a trend of subtle alarmist type thinking from him… which often leads to the sale of some product he’s profiting from.

Super smart guy. Ahead of the curve in optimizing health for sure. But also need to watch for motives carefully there. COI disclosure for me here: I’m going to be profiting from an app I made, soon.

Volume on volume on volume. Don’t manipulate fueling strategies to alter metabolism. Train to get fit. If you’re a natural sprinter, train to increase fitness and volume tolerance. Eat the carbs as needed/desired during training.

My absolute pleasure. You all keep me honest and force me to be current on the research. Too many gol’darn smart folks on this forum to speak out of the side of your mouth. @redlude97 (and a dozen others) will call you (me) out on it immediately.

Wow. That’s awfully generous. Thank you.

Good luck!

I still posit that the only effect reduction of intra-workout carbs has on chronic fat loss is to enhance one’s ability to consume higher volume carb sources, on average, over the course of a fat loss diet phase. This manages satiety better, and facilitates easier adherence to a kcal deficit diet plan.

Regardless of mechanism at play, I hope you have an amazingly successful fat loss phase, and even more, that the weight maintenance phase that follows is permanent and easy to settle into.

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@Crosshair, out of curiosity do you plan to reduce carbs during all training sessions? Or just shorter ones? Or just easier ones regardless of length?

Just cutting out fructose? Or cutting out fructose and scaling back glucose? Or just wholesale general reduction of carb intake?

Hourly rates?

I’d love to hear the deets!

I know you’ve thought about it. I’d like to hear your execution plan.

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@redlude97 my man! Checking these out asap. Thank you.

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After quick perusal of the literature and a couple newer gout systematic reviews and meta-analysis, I can conclude:

I’d need to read about gout and fructose for at least another 8 hours before knowing if I knew anything for sure. :slight_smile:

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Tip of the hat to you for your wisdom there.

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Wise choice!

What is easiest, in nutrition, often actually is a very good choice. Only until proven that it’s not, should folks consider changing. I can support this. :slight_smile:

Your approach makes total sense. Not that you needed or asked for any confirmation from me!

I might chalk it up to you being a very good critical thinker and wanting to ask the right questions. But you may be quite right that it’s just contextual (cyclist vs. gen pop).

In the ultimate display of my cynicism and skepticism towards many wildly successful companies in the nutrition space, I’ll say this:

Every time I’ve felt what you’re feeling about someone, or some claim that I’ve thought was really meaningful and interesting, and I’ve really REALLY dug into the validity of what they’re saying, I pull at the string of questions that stem from the one thing they’re not saying and I end up unraveling the entire argument they’re making.

Much to my chagrin.

I always start listening to a podcast with the hope that I’ll learn something truly valuable. So when I’ve spent 30+ minutes listening, and then I bump into the flaw that invalidates some of their most valuable points, it’s quite disappointing.

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I don’t think there is a such thing as “teaching the body to use fats”. Body prefers carbohydrates for fuel at any time point, so it will first use carbs if they are available. This is why even a low carbohydrate person would be preferentially using carbs if lots of carbs would have been provided to them. I had a chance to measure Marko Baloh, a pretty famous ultra-endurance rider in the lab and his fat oxidation rates have been super high. I asked him if he is doing any low carb work. He said he doesn’t. High carbohydrate intake all the time. Fat oxidation will come naturally with training…

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In my view it isn’t about carbs restriction but rather about calorie intake restriction. I’d rather minimise the fat intake to 0.8 g/kg or lower but maintain high carbohydrate availability. Or your training will suffer… But otherwise - I don’t think that there is an easy way to lose body mass… Everyday stress makes things pretty difficult - I agree!

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This is exactly the perspective I was looking for. Thanks @timpodlogar !!

This is actually what I end up doing when leaning up and has always worked for me in my n=1 case. Not saying fat = 0, but I keep it lower than the maintaining phase and still try to fuel all workouts well. @Dr_Alex_Harrison new project is helping with that :wink:

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Preach!

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Thank the lord. It’s like saying I’m gonna to teach my body to not use the ATP-PCr system first. It just ain’t gonna happen.

Louise Burke’s work on LCHF is the nail in the coffin.

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Well - first we need to discern between adaptations in aerobic capacity and fat oxidation rates. I believe that targeting aerobic capacity makes sense, whereas fat oxidation rates follow the former.
I do fasted rides all the time pretty much because I don’t bother preparing breakfast. I don’t really think I’d benefit from them in any way…
However, if I was after increased adaptations I might sometimes do a muscle glycogen depleted training session but since I like to use my brain and sleep normally, I avoid this kind of workout as it is too stressful.

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Surely the main thing here is if you want to improve your fat ox then you want to raise your LT1 to as high as possible. That way you are then outputting more KJ for a longer time with a more favorable % being used from fat if that is your goal?

Im not sure this is how it works. LT1 defines generally how much fat - carb is used.

For example i just had a recent full lactate VO2 and metabolic profile done. At LT1 and below i was burning roughly 1.4g car and 0.7g fat per min. As far as i understand from the professionals doing this that is the normal ratio and the amount just depends how high your LT1 ish. So someone with a higher LT1 would burn the same ratio but greater amounts irrespective of how they fuel.

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