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>120 g/hr carbohydrate realistic? Discussion on MAX carb consumption rates during exercise.
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Would love to hear stories that hit me right in the confirmation bias about how folks have consumed and benefited from far greater than the oft-cited recommendation of 60-90 g/hr of carbs during endurance activities lasting more than 2 hrs.

I'll start.

1. My first century, ~116g/hr riding a 2006 Trek 1200 with a mix of Tiagra and 105 components. 6'1", 215, ~10% fat. (former strength/power athlete). Completion time: blazing 6 hrs & 30 minutes. Estimated average power: 150-170 W. Total carbs consumed: 750g. Total calories: ??? I stopped for cookies... it was a gran fondo. More than 3300kcal for sure, in total. Was ravenous and hypoglycemic afterwards. Ambient conditions: ~60-70 degrees, sun, calm, comfortably low humidity. (Summer in PNW).

2. More recently, random 2-hr experiment on gut tolerance (just over 2hrs): Consumed ~300g carbs. (~1200kcal). ~150g/hr. 250g carbs from sucrose. 50g from Gatorade. Added 1 tsp sodium citrate. Ambient conditions: ~70-75 degrees, sun, moderate humidity. (Early fall in Carolinas). 6'1", 208, 10% fat (now-lighter, former strength/power athlete). Felt well-fueled and only reasonably hungry afterwards. Estimated average power: 200 W.

I don't intend for this to be a discussion on the utility of such approaches, though happy to entertain any discussion.

Just want to see what folks do for higher carbs.

Alright, brag it up. Let's hear your "I ate/drank THIS much" stories. "This athlete did X" also accepted.

Dr. Alex Harrison | Founder & CEO | Sport Physiology & Performance PhD
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Re: >120 g/hr carbohydrate realistic? Discussion on MAX carb consumption rates during exercise. [DrAlexHarrison] [ In reply to ]
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In a podcast with the MX Endurance guys, I believe Adam Hansen talked about shooting for 120g/hr and doing everything with gels. And he talked about taking a gel halfway thru an IM SWIM to keep the calories going. He was pretty clear that he thought keeping his fueling at this level would definitely be helpful over what he thinks most triathletes are doing, and he said he can do it all day every day basically when cycling.

Interesting ideas for sure. I always thought the idea of 400 calories an hour being the max was counter intuitive, as people are different sizes and shapes. A blanket amount doesn't make much sense.

Looking forward to seeing where this thread goes.

ETA the bold word swim as it's critical haha

DFRU - Detta Family Racing Unit...the kids like it and we all get out and after it...gotta keep the fam involved!
Last edited by: dfru: Dec 30, 20 8:00
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Re: >120 g/hr carbohydrate realistic? Discussion on MAX carb consumption rates during exercise. [DrAlexHarrison] [ In reply to ]
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Sugar is pure energy. The more you can tolerate and digest, the longer you’ll be able to produce high power. Drown yourself in sugar if you never want to bonk

The real trick is dealing with the sugar high effects...

Strava
Last edited by: rsjrv99: Oct 24, 20 17:31
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Re: >120 g/hr carbohydrate realistic? Discussion on MAX carb consumption rates during exercise. [DrAlexHarrison] [ In reply to ]
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The interesting thing for me would not be how many / hr, but how many hours.

I can consume some pretty high cals on the bike, and keep taking those for the 5hrs (6 hours in training). But where' I'm coming unstuck is after the bike where I am dropping the intake, but struggling with the post effects.

So for a 70.3 with the same cal intake on the bike and then the run, I'm A OK. On the bike in IM then I'm fine for the 5 hours. So it's neither the cals on the bike or the cals on the run that are 'flawed', it's the combination of cals on the bike for 5 hours followed by attempting the cals on the run after 2 hours. Obviously hard to test this in training.

(and in answer to your question at 6'4" and 85kg then I've been doing 90g/kg/hr on bike and 60 on the run.
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Re: >120 g/hr carbohydrate realistic? Discussion on MAX carb consumption rates during exercise. [Duncan74] [ In reply to ]
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Duncan74 wrote:
The interesting thing for me would not be how many / hr, but how many hours.

I can consume some pretty high cals on the bike, and keep taking those for the 5hrs (6 hours in training). But where' I'm coming unstuck is after the bike where I am dropping the intake, but struggling with the post effects.

So for a 70.3 with the same cal intake on the bike and then the run, I'm A OK. On the bike in IM then I'm fine for the 5 hours. So it's neither the cals on the bike or the cals on the run that are 'flawed', it's the combination of cals on the bike for 5 hours followed by attempting the cals on the run after 2 hours. Obviously hard to test this in training.

(and in answer to your question at 6'4" and 85kg then I've been doing 90g/kg/hr on bike and 60 on the run.

Would be interested to hear what your hourly fluid and sodium intake is. Entering the run dehydrated could explain the gut disturbance.

What's the glucose fructose ratio in your carb sources?

Dr. Alex Harrison | Founder & CEO | Sport Physiology & Performance PhD
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📱 Check out our app → Saturday: Pro Fuel & Hydration, a performance nutrition coach in your pocket.
Join us on YouTube → Saturday Morning | Ride & Run Faster and our growing Saturday User Hub
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Re: >120 g/hr carbohydrate realistic? Discussion on MAX carb consumption rates during exercise. [DrAlexHarrison] [ In reply to ]
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Don't believe it's dehydration on the bike - I always go pee in T2. I pretty much nail 700ml of nuun an hour on bike.

Where I struggle is then keeping that hydration going in on the run after the 5hrs on the bike. Noting that in training and for 70.3 I'm fine to get the hydration in, just struggle after 5hrs. I will reply later with the details of the intake - I'm a geek so use timers and a strict food plan so just need to grab my wrappers later to get the exact numbers across gels, chomps and bars. (will cheat and fakescan the barcodes into myfitness plan).
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Re: >120 g/hr carbohydrate realistic? Discussion on MAX carb consumption rates during exercise. [Duncan74] [ In reply to ]
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Duncan74 wrote:
Don't believe it's dehydration on the bike - I always go pee in T2. I pretty much nail 700ml of nuun an hour on bike.

Where I struggle is then keeping that hydration going in on the run after the 5hrs on the bike. Noting that in training and for 70.3 I'm fine to get the hydration in, just struggle after 5hrs. I will reply later with the details of the intake - I'm a geek so use timers and a strict food plan so just need to grab my wrappers later to get the exact numbers across gels, chomps and bars. (will cheat and fakescan the barcodes into myfitness plan).

Might be worth trialing 900-1100mL and adding sodium citrate on top of the nuun if your sodium intake is under 1000mg per hour. Has made a difference for a few of my clients but admittedly I've never run after >5hr biking. Longest activities have been 7-10 hrs riding. My longest bricks have been 4hrs tops.

Dr. Alex Harrison | Founder & CEO | Sport Physiology & Performance PhD
-------------------------------------------------------------------------------------------------------------------------------------------------
📱 Check out our app → Saturday: Pro Fuel & Hydration, a performance nutrition coach in your pocket.
Join us on YouTube → Saturday Morning | Ride & Run Faster and our growing Saturday User Hub
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Re: >120 g/hr carbohydrate realistic? Discussion on MAX carb consumption rates during exercise. [DrAlexHarrison] [ In reply to ]
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Interesting discussion. To me it looks like there is maybe a fairly narrow range here.


I'm guessing Duncan74 means 90g per hour. For him that's about 1g per kg per hour on the bike.

DrAlexHarrison, bigger guy, 100+g per hour, also about 1g per kg per hour over a long ride. Not sure how valid rates for short rides are- for example, someone could ride for 5 minutes, drink a glass of orange juice, and claim 1000g per hour.

Me, smaller, 60g per hour on the bike is about what I can handle , also about 1g per kg per hour. On the run I often struggle to take anything though.
Last edited by: fruit thief: Oct 25, 20 2:55
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Re: >120 g/hr carbohydrate realistic? Discussion on MAX carb consumption rates during exercise. [DrAlexHarrison] [ In reply to ]
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I'm sure it's been posted here many times, but FYI:

Last edited by: HardlyTrying: Oct 25, 20 5:15
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Re: >120 g/hr carbohydrate realistic? Discussion on MAX carb consumption rates during exercise. [DrAlexHarrison] [ In reply to ]
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though I have never been too concerned with intake per hour, I have done something to make a very high carb per ml solution. The big thing is osmality. Osmality is related the number of molecules not weight, so for that reason the osmality of maltodextrin (a large molecule is lower than fructose, glucose and sucrose on an equivalent weight basi..We can get into the intro chemistry class on moles etc but you can load a whole lot more calories per ml by using maltodextrin. The energy release kinetiics are nearly identical to sugar but a bit slower. So that is why most energy drinks based upon maltodextrin also have a mix of glucose and fructose added. The three items are cheap and easy to acquire. So I have played with loading maltodextrin plus a small amount of fructose and glucose (plus a bit of sea salt to get a multi mineral blend) to my energy drink to find the tipping point for my stomach. I use a ratio of glucose to fructose of 2:1 and about 30g glucose per bottle of so. Once you find what your stomach will accept I just flavour with lemon and lime juice and off we go.
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Re: >120 g/hr carbohydrate realistic? Discussion on MAX carb consumption rates during exercise. [DrAlexHarrison] [ In reply to ]
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I have a very intolerant stomach and realized I gravitated towards shorter races over the years because I hate the upset stomach/bonk at the two extremes. My only two attempts at multisport races longer than five hours both ended up as dnf's. My best half-IM ever, I guess my muscles were just topped off because I went about 4.5 hours on 40 ounces of water and maybe 200-300 calories.
A couple of years ago I tried my first gravel event--72 miles with 7,000 feet of climbing--and ended up on the side of the trail both bonking and with still with a stomach that seized up after partaking of mid-race hor d'oerves. A very nice rider stayed with me until I could ride back to the start, but I threw up and then could not stomach any food for hours. Since then I have determined I can take in about 100 calories before the start of a long gravel ride and then about 50-100 calories an hour for two to three hours. After that, if I try to consume more my stomach just shuts down. I either finish and perform well or bonk and dnf. My only race this year (Cedar City Fire Road 100K) was a dnf.
My marathoning was the same. First race, undertrained and clueless was still my best because for whatever reason, my muscles were just full that day. I ran pretty fast on just a bit of water. Subsequent attempts with double the mileage and lots more experience never came close to that first effort and several ended on the side of the road bonked, or walking with severe stomach cramps.
If people can really consume that much it must make long events a lot more palatable (pun intended) :)
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Re: >120 g/hr carbohydrate realistic? Discussion on MAX carb consumption rates during exercise. [rsjrv99] [ In reply to ]
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rsjrv99 wrote:

The real trick is dealing with the sugar high effects...

The real trick is dealing with the impaired digestive capability of the digestive tract during high intensity exercise. Eat too much and you end up with bad digestive issues. Bloat, gas, etc.
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Re: >120 g/hr carbohydrate realistic? Discussion on MAX carb consumption rates during exercise. [trail] [ In reply to ]
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A general rule is guidance, however, its a pretty complicated balance

If you race at a high intensity you impair the digestive system's ability to absorb carbs. On a long distance ultra event, I tend to take more real food and more than 90g/hr. If I race an HIM where I am close to threshold most of the time I only take gels and liquids and limit to 100g/hr

On a long distance race, you cannot rely purely on Carbs.... even if you drown yourself in suger, you will still run low as you are using more energy than your body can absorb. If I am racing an Ultra event, I am using around 700Cals per hour, I may be able to absorb 400Cals (at a push), so still have a deficit of 300Cals per hour, which comes from burining fat. During a short event like a HIM I am burining up to 1000Cals per hour, but can absorb 300Cals (due to higher intensity) so I am at a deficit of 700Cals per hour. Therefore I need some level of fat adaptation.
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Re: >120 g/hr carbohydrate realistic? Discussion on MAX carb consumption rates during exercise. [fruit thief] [ In reply to ]
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It's actually a benefit to be 60kg! Carb g/hr tolerance is not related to body mass.
There are a couple of later steps where higher muscle mass might have an influence, but the biggest bottlenecks are much earlier in the GI tract and so size-independent (and trainable).

But to address the OP, I have not had a client able to manage over 100g, and getting up to 90 for a full IM is challenge enough typically. But to be fair, I have also not had a client (including myself) able/willing to commit to the nutritional training a nice high CHO rate requires.

http://www.extramilenutrition.com
Last edited by: greenjp: Oct 26, 20 18:30
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Re: >120 g/hr carbohydrate realistic? Discussion on MAX carb consumption rates during exercise. [DrAlexHarrison] [ In reply to ]
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In an LD-Ironman:
4 powerbar-gels/h.
1 powerbar-gel has 28g carb, lets say 25 because you can't empty the package totally clean => 100 g/h.

During the bike as well as during the run. That's about 36 gels (actually 32 because the first hour on the bike I'm on bars instead of gels).
That's about 0.9 kg carbs on that day. Which is again about 4000 kcal.

Edit: actually it's more, I forgot the intake of carbs by electrolytes like Gatorade. I never calculated this, because I drink electrolyte according to thirst. When it is hot more, when it is cold less.
So I take more than 100 g/h of carbs.

I weigh 85 kg.
Last edited by: longtrousers: Oct 27, 20 3:05
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Re: >120 g/hr carbohydrate realistic? Discussion on MAX carb consumption rates during exercise. [mattsurf] [ In reply to ]
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mattsurf wrote:
Therefore I need some level of fat adaptation.

Everybody has some fat adaption. There was a study* that made a minor splash about 5 years ago where they tested some highly trained athletes, maybe elites, who trained and raced very high carb and found that they burned a surprising amount of fat while running. My memory of that study is quite fuzzy, but I think it's true that you can train to burn more fat, but you still burn some % fat even if not intentionally fat adapted.

*not the FASTER study, which was about the same time.
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Re: >120 g/hr carbohydrate realistic? Discussion on MAX carb consumption rates during exercise. [HardlyTrying] [ In reply to ]
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HardlyTrying wrote:
mattsurf wrote:
Therefore I need some level of fat adaptation.


Everybody has some fat adaption. There was a study* that made a minor splash about 5 years ago where they tested some highly trained athletes, maybe elites, who trained and raced very high carb and found that they burned a surprising amount of fat while running. My memory of that study is quite fuzzy, but I think it's true that you can train to burn more fat, but you still burn some % fat even if not intentionally fat adapted.

*not the FASTER study, which was about the same time.

You are completey correct, everyone burns a combination of Carbs and Fat. I can't remember the exat stats, but even when fueled well on carbs, the body is still getting something like 30% of its energy from Fat while exercising. You can train the body to use a higher percentage of fat, which is the objective of some low carb diets, however, I am not a fan of these at all. Another way is to do lots of long distance training and training fasted so that your body gets accustomed to exercise where supply of carbs is low. This works for me.
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Re: >120 g/hr carbohydrate realistic? Discussion on MAX carb consumption rates during exercise. [mattsurf] [ In reply to ]
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mattsurf wrote:
HardlyTrying wrote:
mattsurf wrote:
Therefore I need some level of fat adaptation.


Everybody has some fat adaption. There was a study* that made a minor splash about 5 years ago where they tested some highly trained athletes, maybe elites, who trained and raced very high carb and found that they burned a surprising amount of fat while running. My memory of that study is quite fuzzy, but I think it's true that you can train to burn more fat, but you still burn some % fat even if not intentionally fat adapted.

*not the FASTER study, which was about the same time.


You are completey correct, everyone burns a combination of Carbs and Fat. I can't remember the exat stats, but even when fueled well on carbs, the body is still getting something like 30% of its energy from Fat while exercising.

If I look at the statistics of tests which I have done, the 30% you mention can only be an average. In fact, as I understand it, at intensities higher than a certain treshold the fat-burning is 0 %.
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Re: >120 g/hr carbohydrate realistic? Discussion on MAX carb consumption rates during exercise. [DrAlexHarrison] [ In reply to ]
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I’ve consumed 500kcal/hr before, so 1.6g/kg/hr of carbohydrate. Takes training and also good pacing.

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Re: >120 g/hr carbohydrate realistic? Discussion on MAX carb consumption rates during exercise. [Duncan74] [ In reply to ]
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Duncan74 wrote:
Don't believe it's dehydration on the bike - I always go pee in T2. I pretty much nail 700ml of nuun an hour on bike.

Where I struggle is then keeping that hydration going in on the run after the 5hrs on the bike. Noting that in training and for 70.3 I'm fine to get the hydration in, just struggle after 5hrs. I will reply later with the details of the intake - I'm a geek so use timers and a strict food plan so just need to grab my wrappers later to get the exact numbers across gels, chomps and bars. (will cheat and fakescan the barcodes into myfitness plan).

You’re dehydrated

Eric Reid AeroFit | Instagram Portfolio
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Re: >120 g/hr carbohydrate realistic? Discussion on MAX carb consumption rates during exercise. [trail] [ In reply to ]
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trail wrote:
rsjrv99 wrote:

The real trick is dealing with the sugar high effects...

The real trick is dealing with the impaired digestive capability of the digestive tract during high intensity exercise. Eat too much and you end up with bad digestive issues. Bloat, gas, etc.

An army marches on its stomach... lose your stomach in an IM and you’re done...

Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”
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Re: >120 g/hr carbohydrate realistic? Discussion on MAX carb consumption rates during exercise. [HardlyTrying] [ In reply to ]
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HardlyTrying wrote:
mattsurf wrote:
Therefore I need some level of fat adaptation.

Everybody has some fat adaption. There was a study* that made a minor splash about 5 years ago where they tested some highly trained athletes, maybe elites, who trained and raced very high carb and found that they burned a surprising amount of fat while running. My memory of that study is quite fuzzy, but I think it's true that you can train to burn more fat, but you still burn some % fat even if not intentionally fat adapted.

*not the FASTER study, which was about the same time.

They’re elite because they burn fat, they don’t burn fat because they’re elite. It’s why they’re elite.

Eric Reid AeroFit | Instagram Portfolio
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“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”
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Re: >120 g/hr carbohydrate realistic? Discussion on MAX carb consumption rates during exercise. [longtrousers] [ In reply to ]
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longtrousers wrote:
mattsurf wrote:
HardlyTrying wrote:
mattsurf wrote:
Therefore I need some level of fat adaptation.


Everybody has some fat adaption. There was a study* that made a minor splash about 5 years ago where they tested some highly trained athletes, maybe elites, who trained and raced very high carb and found that they burned a surprising amount of fat while running. My memory of that study is quite fuzzy, but I think it's true that you can train to burn more fat, but you still burn some % fat even if not intentionally fat adapted.

*not the FASTER study, which was about the same time.


You are completey correct, everyone burns a combination of Carbs and Fat. I can't remember the exat stats, but even when fueled well on carbs, the body is still getting something like 30% of its energy from Fat while exercising.

If I look at the statistics of tests which I have done, the 30% you mention can only be an average. In fact, as I understand it, at intensities higher than a certain treshold the fat-burning is 0 %.

You’re never not burning fat

Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”
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Re: >120 g/hr carbohydrate realistic? Discussion on MAX carb consumption rates during exercise. [ericMPro] [ In reply to ]
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For an AG athlete, I think I am pretty good at nutrition, I certainly know what works for me. However, after 2.5-3 hours I always hit a slight low, I need to back off just a fraction, after 30 minutes or so I am back to 100% and will then stay that way for many hours. I guess that this is the point where my body starts to use fat more effectively. I have done enough events to know that this is completely normal for me, and that there is no need to panic of change anything.

So a question for Eric, would this be typical for elite athletes, or are they sufficiently trained and adapted that there is no noticeable transition?
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Re: >120 g/hr carbohydrate realistic? Discussion on MAX carb consumption rates during exercise. [mattsurf] [ In reply to ]
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mattsurf wrote:

For an AG athlete, I think I am pretty good at nutrition, I certainly know what works for me. However, after 2.5-3 hours I always hit a slight low, I need to back off just a fraction, after 30 minutes or so I am back to 100% and will then stay that way for many hours. I guess that this is the point where my body starts to use fat more effectively. I have done enough events to know that this is completely normal for me, and that there is no need to panic of change anything.

So a question for Eric, would this be typical for elite athletes, or are they sufficiently trained and adapted that there is no noticeable transition?

Elite athletes are elite, extreme outliers. They're not just better versions of you.

That said, we're all the same kind of different... even elite athletes experience seemingly similar ups and downs.

Eric Reid AeroFit | Instagram Portfolio
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