Bingo! Multiple transportable sugars is key. Newer research pretty clearly indicates we can go a lot higher than the old dogma of 60/30/90 (60 glucose, 30 fructose, 90 total). Please let those numbers die!
Here’s 3 awesome sources that say so. (PDFs attached, I think… I’m new to this specific forum)
I routinely do ~75g glucose, 60g fructose, and ~135g total carbs per hour on rides lasting 2-5 hrs.
With utmost respect for Dr. Asker Jeukendrup who is a legend and pioneer in the field of intra-workout fueling strategy, that article, and some of the recommendations that stem from his earlier work that continue to make their way into position stands of the ISSN are probably leaving vast swaths of cyclists and triathletes:
Underfueled.
With an overemphasis on complexity of beverage (malto plus fruc plus sucrose plus gluc confusion)
Overconsuming glucose slightly, and vastly underconsuming fructose.
So for workouts < 1hr, the carbs are not adding much to fuel, because we should have enough stored. But it could help with lowering RPE. So fructose could still help for shorter workouts even if the energy from it only comes after an hour.
I also like to add some citric acid for flavor, cancels out a bit of the sweetness.
Regarding how maltodextrin gets processed in the stomach, first it is cut into glucose before it ultimately gets absorbed. Does that mean you still need to take as much water per gram of maltodextrin as you do for glucose?
Water needs are actually more predicated on energy density of the consumption, rather than osmolarity, FYI. Osmolarity is reduced by using maltodextrin. Energy density is not.
In general, water needs will be similar, regardless of malto vs. gluc use. Maybe 10% less water could be safely trialed while using malto instead of gluc.
But better yet, use sucrose to get your fructose + glucose. When targeting near 1:1 ratio of gluc:fruc (which I assure you is better than 2:1), sucrose alone is a lower osmolarity than malto+fruc.
No, unfortunately. Sodium citrate replaces three hydrogens on the three hydroxyl groups of citric acid with sodium molecules. Once dissolved sodium citrate turns into 3 x Na+ and 1x citrate ion.
Once dissolved citric acid only has hydrogen ions to donate. Okay for sweetness-reduction. Useless for meeting sodium needs though!
Total FYI:
Using sodium citrate in place of table salt allows your gut to tolerate more sodium consumption during training. Sodium citrate has 3 sodium molecules for every 1 citrate molecule. Sodium chloride has 1 sodium molecule for every 1 chloride molecule. That means that for the same amount of sodium consumption, there will be a greater number of molecules ingested, if using table salt, rather than sodium citrate. Osmolarity is the number of molecules per unit volume of solution. Our gastrointestinal tracts are sensitive to very high osmolarity solutions. During normal daily living, consumption of very high osmolar solutions (lots of molecules per liter) causes a laxative effect 20-60 minutes after consumption. During exercise, it causes gut cramping, THEN a laxative effect. My personal experience with this can be described as “not fun!”
I mix 1/2 cup maltodextrin, 60 grams of carbs, with 2 TBSPS of fructose, 33 grams of carbs, and a lemon lime flavor packet in 24 ounces of water. That’s around 375 calories. A gram of Maltodextrin or fructose yields about a gram of carbs. It would be easy to increase that to exceed 100 grams of carbs. I wouldn’t want to do a 1 to 1 ratio of glucose to fructose because it would be too sweet tasting.
I do several long slow rides/week, 3+ hours at around 75% of my FTP which burns around 1,300 or more calories. I drink a few swallows from the bottle every 30 minutes or so throughout the ride. At the ½ way point I stop at a c-store and have a Starbucks vanilla double shot, 210 calories, and a Natures Bakery fig bar, 200 calories. That comes to about 785 calories total for the ride. When I finish I have 16 ounces of chocolate milk for a recovery drink, about 360 calories. I typically have a serving of cereal with milk and blueberries and 3 eggs for breakfast before the ride.
If I’m going to ride longer and/or harder I’ll take two bottles. In the summer I fill a camelback with just water and add a little bit of sodium citrate to the bottle. I live in north central Texas and it gets very hot here in the summer. Lots of sweat!
I am taking in fewer carbs during the ride than I’m burning but not by much.
Describing this is making me hungry!
Is it energy density that matters or the ultimate number of particles that the carbohydrates are broken down before absorbed in the bloodstream? I guess it doesn’t matter if only adding carbohydrates to water. So how much water do we need then, it looks like 50g of fructose per liter gives about the right osmolarity, does that mean we should aim for 1L of water per 50g of carbs, regardless of where they came from?
Although I just did 1 bottle of 800ml with 120g sucrose and 60g of maltodextrin plus 1 bottle of only water, for a 2 hour workout. That felt quite good.
Will try a higher concentration of fructose next.
Now wondering if/how a GLU+FRUC mixture differs from a straight SUC solution?
There is no need to break the G-F mixture (as there is with SUC) for absorption, so what effect does this have on the body (e.g. hormone release, etc.)?
Energy density matters more than osmolarity (molecule number) by a wide margin. So much so that some of my peers pay absolutely no attention to osmolarity anymore.
Alex,
what are your thoughts/tips on using a concentrated bottle for nutrition?
For the bike leg of my last IM I mixed 280g of maltodextrin in an 800mL bottle, which would last for 4h (so 70g of carbs per hour). After every sip of the concentrate, I would take an equal sip of water in order to avoid any stomach issues. While it did seem to work, I am interested in improving the mix by adding fructose.
Thanks for your contributions, it has been interesting reading.
I am getting so confused between the types of sugar.
So feasibly you could just mix 100g table sugar (sucrose?) with water and you’d have a even split (50-50) between glucose and fructose?
But in your slowtwitch posts, you suggest mixing Gatorade with table sugar, is that to make it more palatable as 100g of table sugar would be too sweet? What type of sugar is in Gatorade? Isn’t it a mix of glucose and fructose already?
Thanks for posting btw, it’s useful to be able to clarify.
This bit still hurts my head a little. I always wondered how fuelling anything under an hour could help as I always hear people saying you need to fuel 3 or so hours before a ride. So how does fuelling while on a 60 minute trainer session help?
The 3 hours in advance thing is when you have a complete meal as part of normal nutrition. You might eat more carbs than normal in preparation of an intense workout and what this does is fill up your glycogen storage, I believe this is in the liver and in the muscles.
During the workout it only makes sense to ingest quick carbs that are much faster absorbed. So sugar in water just takes minutes. For workouts shorter than 1 hour it is not an absolute necessity to eat, because you should have enough energy stored.
But, ingesting quick carbs during the workout, also shorter ones, for me makes the workout easier and that is also what others have experienced. I can imagine a few reasons why:
Our bodies are not digital on/off machines and there are mechanisms in place to protect you from dying if you forget to eat. So your glycogen storage is not like a fuel tank that can be used at full speed until empty, rather your body starts to slow down fuel consumption before it runs out. So by ingesting glucose, you will stay longer out of the almost empty zone where less glycogen is delivered to the muscles.
For fructose I can also imagine that although it takes a long time before it is actually used as glycogen, just absorbing it might already tell your body that glycogen is on the way and it could already release more of the stored glycogen. I know it works like that if you just rinse your mouth with something sweet.
