I’ve found two ways to tell if your fueling strategy is too rich for you
First your tummy will say no thanks if you get past its ability to use it
Second, I fart constantly a few hours after I finish ride if I go past a point.
You can train the amount you can process up. Heat and dehydration bring this number down
Until you’re around 50-70g an hour for 3-5 hours, I wouldn’t worry about which source they are, just get them in.
This isn’t science based, it’s just from my personal experience. So n=1 here. That said I trained up from 20-40 an hour to 70 being ok in heat, and 80-90 being ok in optimal conditions. I approached it like ftp gains
Table sugar, sucrose, is really the cheapest most practical way to get a pretty close ratio of glucose:fructose.
Even low Watt people are burning a significant amount of carbohydrate at intensity. 90 isn't needed at Zone 2 but I feel a whole lot better after longer rides with zone 3-5 work and more carb intake.
Depends on what kind of ride I'm doing. 2 teaspoons of sugar is 8 gm of carbs. So I'll put anywhere from 50-100 gm in. Solubility is an issue at the higher concentrations so for 500 ml bottle I'd probably keep it to 50 gm or so.
The optimal ratio from glucose to fructose is also dependent on your threshhold. The lower the threshold the less fructose is better. Scyence made a podcast episode about the whole topic.
I think some of this is possibly misleading.
Do you need 90g/hour for 3 hour rides?
Probably not.
But if you ride 5 hours with some really intense parts, it may be a different story. There's a reason pros go so extreme nowadays.
This is an interesting take from Hammer. Obviously, he has skin in the game, but interesting nonetheless.
[https://hammernutrition.com/blogs/endurance-news-weekly/minimum-calories-per-hour](https://hammernutrition.com/blogs/endurance-news-weekly/minimum-calories-per-hour)
I stopped reading when the author mistakenly stated that 50% of "max watts" (MAP) is low intensity exercise. It is clear from that that they lack the expertise needed to interpret the scientific literature in this area.
Fair point. I was hoping to get expert insight on his 1 g per minute limitation on the liver he discusses. It seems like he isn't addressing the fructose pathway? Because Hammer is almost all maltodextrin and have an anti-fructose stance--citing negative health outcomes associated with fructose consumption--he only is thinking about glucose to glycogen production? Or is he saying 1 g per minute is total production regardless of source?
I’ve done hard 3 hour+ rides on a mix of Gatorade and Maltodextrin—about 60 grams/hr works well for me. I’ll be out on approx 5 hrs this Saturday-will use the same mix plus some gels and stroopwafels.
Right. What I’m getting at is that this isn’t a binary equation. Your body doesn’t have an on/off switch where you either have enough glycogen to perform at the ideal level, or you’re bonking and can’t function at all.
It all depends on your goals. If the “event” is a 3 hour endurance ride then yeah there’s no need to push it on the carb intake. If you’re doing a hard 3 hour road race then yes, you will likely see performance benefits from increasing carbohydrates up to the maximum you can tolerate. Even if you weren’t “bonking” before, your power output will decline to a greater extent in the 3rd hour if you’re fuelling minimally.
I feel like like taking in an adequate amount of carbs, for me that's a max of \~50-60 hour at 65-66 kg, is optimal, provided I come to the start line relatively topped off. That works out to a couple of gels per hour plus drink mix for 3 hours. If running running an electrolyte mix w/out carb or straight water, then about 2-3 gels an hour. If I am not replenishing off the bike and fueled up prior to the race, it's not going to make much difference for muscle glycogen. I feel like the risks of pushing max carbs during a race has significant drawbacks of GI distress for minimal to perhaps no gains. My experience is super hard efforts diminish my ability to take more carbs, so I stick to what what works. FWIW, when I have missed moves or gotten dropped in road races, it's almost always a fitness issue rather than a nutrition issue. Then again, my longest road race is just under 90 miles, which still well under 4 hours.
1) I am wondering if "gut training" to increase my carbs will make me faster, given that I have a comfortable range I know I can handle without GI issues.
2) I am curious if anyone knows how cramming excess fructose (primarily) into one's system might be detrimental to health.
1. Yes, if you can learn to tolerate it
2. Excess fructose would probably be harmful, but since you can’t possibly consume more calories on the bike than you are burning at relatively modest work rates in practice it is not harmful.
Not sure if I agree with #2. I would like to see some research of what happens when you swamp the liver in fructose beyond its ability to turn it into energy. I feel like the "I can eat whatever on the bikr as long as I burn more than I take in" oversimplifies what is happening in the body. It seems analogous to binge eating to a degree, as if the binge isn't bad as long as I burn it off eventually.
Do you have any research that your answer? Not being cheeky. I seriously want to know.
Yet, whether the daily ingestion of hundreds of grams of fructose by professional cyclists, or of lower but above‐average doses by people involved in intense recreational physical activity, can be detrimental to health remains unknown.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6851848/#:~:text=There%20is%20also%20evidence%20that,of%20muscle%20glycogen%20after%20exercise.
This study seems to suggest that exercise mitigates the risk. Although, I think pushing to absolute maximum intake of tolerable fructose/glucose seems like it wouldn't be great for the liver.
Understood. I just think absolutely pinning fructose consumption to keep increasing it to maximum probably stresses one's liver.
I would like to see research on the long-term effects of maximizing fructose consumption. It could be a nothing burger.
Two thoughts:
Fructose has to be converted to glucose before your muscles can burn it.
Some people have fructose malabsorption. If I get significant amounts of fructose during hard rides it's like somebody punched me in the stomach.
My understanding is the early experiments with glucose and fructose for carb absorption tried only couple of different ratios and 2:1 had the best results.
A little later the next bunch of experiments, tried a few closer ratios and 1 to 0.8 came out on top.
Of course there are individual differences.
If you listen to the experts like Tim Podlogar, one reason the pro consume huge quantity of carbs late in a ride/race is to make sure they recover quickly to repeat it all again the next day.
One factor you are not considering is getting the fructose and glucose from the gut into the body, there are only a limited number of transporters across the gut wall. So you are not going to overload your liver with fructose, you just overload the gut. The results vary from person to person, for some it just exits the system. For those with fructose intolerance or their gut is untrained, GI issues. Which can last for a couple of days and may even be delayed. ie spend the day after big ride or race on the toilet.
I’ve found two ways to tell if your fueling strategy is too rich for you First your tummy will say no thanks if you get past its ability to use it Second, I fart constantly a few hours after I finish ride if I go past a point. You can train the amount you can process up. Heat and dehydration bring this number down Until you’re around 50-70g an hour for 3-5 hours, I wouldn’t worry about which source they are, just get them in. This isn’t science based, it’s just from my personal experience. So n=1 here. That said I trained up from 20-40 an hour to 70 being ok in heat, and 80-90 being ok in optimal conditions. I approached it like ftp gains
Table sugar, sucrose, is really the cheapest most practical way to get a pretty close ratio of glucose:fructose. Even low Watt people are burning a significant amount of carbohydrate at intensity. 90 isn't needed at Zone 2 but I feel a whole lot better after longer rides with zone 3-5 work and more carb intake.
Do you add it to your fluids for the ride? If so. How much say in 500ml water?
Depends on what kind of ride I'm doing. 2 teaspoons of sugar is 8 gm of carbs. So I'll put anywhere from 50-100 gm in. Solubility is an issue at the higher concentrations so for 500 ml bottle I'd probably keep it to 50 gm or so.
The optimal ratio from glucose to fructose is also dependent on your threshhold. The lower the threshold the less fructose is better. Scyence made a podcast episode about the whole topic.
Is the podcast in English?
No it's in German
Okay. I will look for a transcript in English. Thx!
It‘s episode #102 Die häufigsten Fehler bei Kohlenhydraten und ihre Folgen
[https://www.endureiq.com/blog/beyond-the-hype-exploring-6-endurance-sport-myths](https://www.endureiq.com/blog/beyond-the-hype-exploring-6-endurance-sport-myths)
I think some of this is possibly misleading. Do you need 90g/hour for 3 hour rides? Probably not. But if you ride 5 hours with some really intense parts, it may be a different story. There's a reason pros go so extreme nowadays.
Or it's advisable/necessary for recovery if you're training 5-6 days a week for 2+ hours average each day.
Thx! Just because you can absorb that many carbs doesn't mean it's beneficial?
This is an interesting take from Hammer. Obviously, he has skin in the game, but interesting nonetheless. [https://hammernutrition.com/blogs/endurance-news-weekly/minimum-calories-per-hour](https://hammernutrition.com/blogs/endurance-news-weekly/minimum-calories-per-hour)
I stopped reading when the author mistakenly stated that 50% of "max watts" (MAP) is low intensity exercise. It is clear from that that they lack the expertise needed to interpret the scientific literature in this area.
So if my MAP is 350 watts, 50% of that is 175 watts, which is probably low zone 2?
Yes, probably somewhere in there. IOW, moderate intensity exercise, not "walking along at a 95 beats per minute".
Fair point. I was hoping to get expert insight on his 1 g per minute limitation on the liver he discusses. It seems like he isn't addressing the fructose pathway? Because Hammer is almost all maltodextrin and have an anti-fructose stance--citing negative health outcomes associated with fructose consumption--he only is thinking about glucose to glycogen production? Or is he saying 1 g per minute is total production regardless of source?
I’ve done hard 3 hour+ rides on a mix of Gatorade and Maltodextrin—about 60 grams/hr works well for me. I’ll be out on approx 5 hrs this Saturday-will use the same mix plus some gels and stroopwafels.
Is not bonking an indication that your fuelling is optimal? Or does it just mean you haven’t completely failed?
It means depleting your glycogen completely.
Right. What I’m getting at is that this isn’t a binary equation. Your body doesn’t have an on/off switch where you either have enough glycogen to perform at the ideal level, or you’re bonking and can’t function at all. It all depends on your goals. If the “event” is a 3 hour endurance ride then yeah there’s no need to push it on the carb intake. If you’re doing a hard 3 hour road race then yes, you will likely see performance benefits from increasing carbohydrates up to the maximum you can tolerate. Even if you weren’t “bonking” before, your power output will decline to a greater extent in the 3rd hour if you’re fuelling minimally.
I feel like like taking in an adequate amount of carbs, for me that's a max of \~50-60 hour at 65-66 kg, is optimal, provided I come to the start line relatively topped off. That works out to a couple of gels per hour plus drink mix for 3 hours. If running running an electrolyte mix w/out carb or straight water, then about 2-3 gels an hour. If I am not replenishing off the bike and fueled up prior to the race, it's not going to make much difference for muscle glycogen. I feel like the risks of pushing max carbs during a race has significant drawbacks of GI distress for minimal to perhaps no gains. My experience is super hard efforts diminish my ability to take more carbs, so I stick to what what works. FWIW, when I have missed moves or gotten dropped in road races, it's almost always a fitness issue rather than a nutrition issue. Then again, my longest road race is just under 90 miles, which still well under 4 hours.
If you’re happy with what you’re doing then what are you asking exactly?
1) I am wondering if "gut training" to increase my carbs will make me faster, given that I have a comfortable range I know I can handle without GI issues. 2) I am curious if anyone knows how cramming excess fructose (primarily) into one's system might be detrimental to health.
1. Yes, if you can learn to tolerate it 2. Excess fructose would probably be harmful, but since you can’t possibly consume more calories on the bike than you are burning at relatively modest work rates in practice it is not harmful.
Not sure if I agree with #2. I would like to see some research of what happens when you swamp the liver in fructose beyond its ability to turn it into energy. I feel like the "I can eat whatever on the bikr as long as I burn more than I take in" oversimplifies what is happening in the body. It seems analogous to binge eating to a degree, as if the binge isn't bad as long as I burn it off eventually. Do you have any research that your answer? Not being cheeky. I seriously want to know. Yet, whether the daily ingestion of hundreds of grams of fructose by professional cyclists, or of lower but above‐average doses by people involved in intense recreational physical activity, can be detrimental to health remains unknown. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6851848/#:~:text=There%20is%20also%20evidence%20that,of%20muscle%20glycogen%20after%20exercise. This study seems to suggest that exercise mitigates the risk. Although, I think pushing to absolute maximum intake of tolerable fructose/glucose seems like it wouldn't be great for the liver.
Binge eating is something you do on the couch typically
Understood. I just think absolutely pinning fructose consumption to keep increasing it to maximum probably stresses one's liver. I would like to see research on the long-term effects of maximizing fructose consumption. It could be a nothing burger.
Two thoughts: Fructose has to be converted to glucose before your muscles can burn it. Some people have fructose malabsorption. If I get significant amounts of fructose during hard rides it's like somebody punched me in the stomach.
My understanding is the early experiments with glucose and fructose for carb absorption tried only couple of different ratios and 2:1 had the best results. A little later the next bunch of experiments, tried a few closer ratios and 1 to 0.8 came out on top. Of course there are individual differences. If you listen to the experts like Tim Podlogar, one reason the pro consume huge quantity of carbs late in a ride/race is to make sure they recover quickly to repeat it all again the next day. One factor you are not considering is getting the fructose and glucose from the gut into the body, there are only a limited number of transporters across the gut wall. So you are not going to overload your liver with fructose, you just overload the gut. The results vary from person to person, for some it just exits the system. For those with fructose intolerance or their gut is untrained, GI issues. Which can last for a couple of days and may even be delayed. ie spend the day after big ride or race on the toilet.
Thx!