Used this with 50ml of cordial (vimto in this instance). Definitely made the difference and I’m happy with the outcome.
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I guess you are using the bulk powder 50-50 mix? I throw in one measure of their electrolyte powder when making it and call it good. I also make my own recovery drink with their whey protein and pure maltodexterine. I gave up on fructose based products after too much stomach discomfort every weekend!
Yes. And basically I just put in the correct number of scoops of their electrolyte powder for the number of bottles I worked out the mix should do. That was just to avoid an extra step really when making the bottles. It’s working well with Vimto as the cordial anyway!
Despite the podcast discussion/ advice, I still tend to go for yogurt/ protein/ berries/ granola for recovery after a longer spin or workout.
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That sounds a good recovery plan tbh, I’m a bit bored of the whole recovery supplement thing. I’m pretty sure with good food you can be just as effective with these things. (On the bike’s a different story however.)
I use bulkpowders 50/50 mix and add fructose fot rn additional carb source. I don’t get stomach discomfort from that. I also use their protein powder with maltodextrine as recovery.
I used to bonk often and hard at the end of long zone 2/endurance rides but since I started with these drinks I never do 
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Puzzling for me are the isotonic dilution rates. I understand Maltodextrin requires 3.3ml/g and Fructose 26ml/g in order to be isotonic.
If that’s true then for 80g of 2:1 glucose to fructose you’d need 864ml of water. Correct? So what dilution is really being aimed for here?
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Well, summarising the info above, looking at the links provided by all the guys above, the conclusion I get to is:
For short events, use maltodextrin or dextrose (ie not fructose, because although fructose will be absorbed and help you get above the 60-70g per hour by consuming glucose alone, the rate at which fructose can make a meaningful difference in the muscles is much longer - Nutriton Myth Busting: Why NOT to Use Fructose For Exercise | AU).
For events above 2 hours (SIS say 3-4 hours), fructose would start to provide a meaningful benefit – but this fuelling should be practiced in training, because some folks experience gastric issues with fructose.
When mixing maltodextrin, dextrose or fructose with water for consumption, bear in mind it is both individual and trainable. However, maltodextrin appears to need considerably less water to move out of the stomach. So, a starting point for a 2h race could be 66g maltodextrin and 200ml water per hour, or 150g in a 500ml bottle that you start sipping 15mins before the gun goes.
To get the same from dextrose, you could start with 63g dextrose per 1200ml per hour to achieve the same osmolality. If you are mixing dextrose/glucose/fructose in a more concentrated drink than this, then the stomach will push water into the drink you have just consumed to adjust the dilution (osmolality). This process can cause discomfort, as your drink may be held in your stomach until it can be sufficiently diluted to continue its progress to your small intestine.
So, if you’re getting stomach issues with higher concentrations of dextrose/glucose, try either weakening the mix or switching to maltodextrin – or a 50/50 mix.
However, maltodextrin is a polymer of lots of glucose molecules, and can’t be absorbed as maltodextrin. Your body will break down maltodextrin into glucose in your mouth (a little) and in your small intestine, using amylase. So, however you drunk it, you are getting glucose and water in the small intestine ready for absorption. If you used maltodextrin, now converted to glucose by amylase, your body will have to add a lot of water to maintain osmolality in the small intestine.
This water has to come from somewhere, and hence the link between hydration and carbohydrate ingestion. Taking onboard high quantities of carbohydrate through maltodextrin seems much more likely to lead to dehydration. So, there’s a trade-off in terms of what each individual needs most; fuel or hydration? Probably we all need to experiment a bit to find out.
The research suggests that if you’re getting stomach issues, first reduce or eliminate fructose (especially if your events are less than 4 hours). Then, increase maltodextrin and reduce dextrose/glucose, because this will help the drink pass through your stomach more easily. Finally, monitor hydration levels.
Conversely, if hydration is more important to you (you perspire heavily or you’re racing in the heat) you may want either dextrose or maltodextrin supplemented with water.
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@redlude97, I will do my best; I’ll try to pick out the relevant bits so the conversation stays useful to anyone following but if you think I’m selectively picking bits out, please do call me out! I’m sorry its a long post…
Below (linked) is a pretty simple description (and I’m a simple bear). In particular, I’m taking away:
"Large quantities of water are secreted into the lumen of the small intestine during the digestive process. …water flows across the mucosa in response to osmotic gradients. [One reason for these gradients is]
Increases in luminal osmotic pressure resulting from influx and digestion of foodstuffs: The chyme that floods into the intestine from the stomach typically is not terribly hyperosmotic [ie as you were saying above, to leave the stomach, liquid should be fairly close to 300mOsm/kg, which for dextrose/glucose requires much more water than maltodextrin]
but as its macromolecular components are digested, osmolarlity of that solution increases dramatically.
Starch, for example, is a huge molecule that contributes only a small amount to osmotic pressure, but as it is digested, thousands of molecules of maltose are generated, each of which is as osmotically active as the original starch molecule."
http://www.vivo.colostate.edu/hbooks/pathphys/digestion/smallgut/secretion.html
I read the link you posted “Fate of ingested fluids…” and its really interesting (well worth a read, others!) - Table 1 on gastric emptying suggests that energy density is more of an inhibitor to allowing fluid to flow into the small intestine than osmolality! That puts a perspective on all this. Also noted that there is very considerable variation in emptying rates between individuals.
I did note that the link states “Surprisingly, the rate of gastric emptying is regulated such that approximately isoenergetic amounts of carbohydrates, proteins, fats, and alcohol 34,42,43 are delivered into the duodenum.” You could interpret this as both maltodextrin and dextrose/glucose empty at the same rate in terms of energy load.
This is a key passage (to me):
“Several studies have examined the effect of replacing glucose monomer with polymers on gastric emptying, but the findings are not consistent. Most investigations have found little or no difference in gastric emptying of isoenergetic solutions of glucose monomers compared with glucose polymers, despite the often large differences in osmolality”
And the conclusion on stomach emptying:
“Consensus opinion at present is that the energy density of a solution exerts a greater effect than osmolality in the regulation of gastric emptying and that the substitution of glucose polymer for monomer may slightly increase the rate of gastric emptying, but only at high energy densities.”
'Moving onto the small intestine and absorbtion:
“The stomach contents delivered to the duodenum are rapidly brought into osmotic equilibrium with the circulating plasma. This appears to be brought about by bidirectional movement of water and electrolytes across the intestinal lumen along osmotic and electrochemical gradients.” I take this to mean that anything you eat/drink will be brought to osmolality either within the stomach or lumen before absorption. So, you drink a weak carb solution and your body doesn’t have to add much water; you eat a gel, and it does have to add plenty of water.
The key paragraph is here:
“The substitution of… maltodextrins for equimolar amounts of glucose monomers has been reported to increase glucose absorption… However, it is not a universal finding that glucose absorption is faster from maltodextrins than from equivalent concentrations of glucose monomers.”
Sadly, none of this is 100% conclusive on 1) which carb, 2) how much to dilute it, and 3) effect on hydration. And I think we all agree; everyone is different!
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Do other forms of carbs also use the same transport systems as glucose and fructose. Specifically for potatoes, clif bars, or rices cakes?
Complex carbs (like rice, potatoes) are all going to get broken down into simple carbs (monosaccharides) and most of this happens in the small intestine. They are then absorbed using one of two pathways: SGLT1 for glucose or galactose, and GLUT5 for fructose. So you can’t get a win by maxing out on maltodextrin in a drink and then having a potato on top!
I agree, @redlude97. All the companies offering carb drinks have done their homework and testing, and they are in the right ballpark for most folks. If you’re thinking that its not working for you then experiment. Play around. The current environment might be a good time to try new stuff without risking race performance. And with such a large range or responses in testing, together with the number of options, folks are unlikely ever to find the absolute optimum - find something that you like, and seems to work. Try it in training to get used to it and improve your tolerance.
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But you can’t because they mix together and effect each other. I guess for short efforts people might not be hitting a hydration wall. But throw in multi hour efforts and hydration is key. People racing DK200 on beta fuel and then having a bad day and wondering why. But I got in my 100g/hr, I don’t understand what went wrong 
I don’t mix my hydration and fueling (other than skratch) . That’s what sis and maurten do and what you are pushing. Im saying that you cant increase fueling without effecting hydration and therefore cant talk about them separately.
Agreed. Which is why I prefer to keep them separate on bike so that I can adjust them separately. But I know that if I adjust my calories up I have to up water too. Other way around doesn’t matter. But for scientific discussion, you have to talk about both as they effect each other.
That depends on what the appropriate ratios are. They aren’t beta fuel ratios. And sis, much like yourself, talks about isotonic in terms of stomach, where it’s still mainly Maltodextrin. It’s no longer isotonic in small intestines where the Maltodextrin becomes glucose molecules.
We’re not trying to maximize hydration and fueling for when we sit on the couch eating sis gels. We are pushing ourselves to our limits and sweating and we have to replace that water lost as well. Which means we care about maximum water, electrolyte, and carb absorption. Your scope is too small. If you want a study, read the study you posted it’s all in there for maximizing both hydration and fueling.
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. Agreed that it does create logistical issues. I come pretty close, but yeah I would always like to carry less weight. For pros these logistical issues are non existent as they have cars to give them bottles. The necessity is determined by the length and environmental factors. So sometimes it is necessary. 3L/hr seems high, I’ll need to recheck that.
But when we discuss fact and science, we need to report it as such. Logistical issues don’t matter to the fact. It is up to each person to determine how much they can logistically support. And it’s not black and white. Any extra water you can add to bring the concentration down will help. Stopping at a feed stop to refill bottles? Chug an extra bottle of just water while you are there. But we need to express the fact correctly.
Good question. And I’ll reference the study you posted as well as the skratch article I posted.
It is now well recognized that solutions with a carbohydrate content of ≤2.5% empty from the stomach at essentially the same rate as that of equal volumes of water,47 and most studies have shown that carbohydrate levels ≥6% unequivocally slow emptying.
The short answer to the first question is that our Sport Hydration Drink Mix is only 80 Calories per serving because it is our experience that a 4% carbohydrate solution
Depending on one’s hydration state, blood osmolality can range anywhere from 275 to 295 mOsmol per kg of water. Our Sport Hydration Drink Mix has an osmolality of 160 mOsmol per kg of water, primarily because of the lower concentration of carbohydrate that we use and the absence of excess ingredients like coloring agents, flavoring agents, preservatives, and emulsifiers."
We can’t disprove things by going to a ridiculous extent, ie “perfectly matched”. It’s also not a 0 or 1. Those quotes express what we should aim for. Our discussion started because folks were talking about increasing their hourly carb intake. I expressed that it needs to be matched with extra water. Just increasing carbs trends you in the wrong direction. Any additional water trends you in a better direction. So I can’t say you are doing it wrong if you don’t get down to exactly 4-6%. And that’s not what I said. I just said that an increase in carbs needs matched with some water.
I just did some calculation based on the intake I have been using.
Per Hour
2 x 680ml bottles skratch = 60g carbs
1 x sis gel = 25g carbs
That’s 85g per 1360ml = 6.25% carb solution while taking in 340cal/hr. So it doesn’t require 3L/hr.
I just used the gel above as an example. Sometimes it’s a sis gel, sometimes something else. I have pushed my calorie intake closer to 400cal/hr. I’m always maximizing the 2:1 glucose:fructose ratio. In times I haven’t matched that with a little extra water intake, I have hit a hydration wall and had a long slow ride home. With extra water I can push 400cal with no issue which I’ve done over 6-8hr rides before.
For fueling yes you can just eat the gel. But we need hydration was well. So for proper hydration and fueling yes it does need water. And I don’t know how you think my previous post contradicts that? I gave an example of 2 x skratch bottles and a gel per hour. I’m getting water with the gel
Which product is this? Those numbers don’t make any sense. What product says 4.5 bottles per scoop?
Again, you are just looking at fueling. We want fueling and hydration. Hydration is way more important, but it is possible to get both. And why incorporate a strategy that results in “decrease in emptying” when you can have a strategy that promotes emptying and still reaches ~90g/hr?
Hydration isn’t necessary? And the “slightly faster with more water” should end this argument.