When it comes to sports nutrition for endurance events, I firmly believe that keeping it simple is the best road to success. What does your body need while you are exercising, even for very long periods of time as in an Ironman? In order of priority, it needs water, carbohydrates, and electrolytes (primarily sodium and potassium). That's it. All of the other stuff, in my opinion, is just marketing "fluff". Your body certainly doesn't need protein (or amino acids) or fat, or vitamins, or minerals during exercise. It's in a state of shock and in no case would it ever turn to protein or fat sources of nutrition for energy over a carbohydrate. Your body's primary goal, above all else, is to get glucose (the simplest carbohydrate) to your brain, your heart, and all the muscles of your body as fast as possible. Anything else in your stomach besides carbohydrates is, in many cases, going to promote gastrointestinal distress during exercise. Now you certainly need all that other stuff after exercise for recovery, and how you choose to accomplish that is completely up to you, but again, I would tend to promote a well-balanced diet over mixing up designer recovery shakes.
So how does one get glucose into the body as fast as possible during exercise? Well, I've been a fairly outspoken advocate of plain maltodextrin on internet forums like slowtwitch.com, and I won't delve completely into the subject now, but I will briefly explain why maltodextrin is a good option. Cyclists have realized for many years that plain maltodextrin works well for supplying glucose to the body during exercise. Maltodextrin is a synthetic polymer of glucose linked in chains of about 10-20. The great thing about maltodextrin is that it is absorbed from the gut as glucose nearly identically as fast as plain old, raw glucose. But, the fact that it is a larger molecule means you can make very concentrated solutions of maltodextrin and avoid making them extremely hypertonic to human plasma. One common misconception that I think is worth mentioning, is the idea that is often thrown around that you want "extended release" (or low glycemic index) carbohydrates during exercise. This is simply not true. In theory, you would want the "fastest release" (or highest glycemic index) carbohydrate as possible all the time. Like I said, the primary goal is to deliver a constant supply of glucose to your body as fast as possible. Glucose then, would theoretically be the best fuel. But as I have already mentioned, the problem with glucose is that concentrated solutions of it are very hypertonic and simply not practical for use during exercise. Thus, maltodextrin is the next best option. The other great thing about maltodextrin, is that it's pretty much dirt cheap. Commercially, it's used in beer distillation, so you can typically buy it in bulk from a beer supply store for less than $2.00 per pound.
Now, for my review and comparison of plain maltodextrin with one of the leading "designer" products out there, Infinit nutrition. I would like to thank Michael, at Infinit nutrition, who generously provided me with a bag of custom product to try.
Carbohydrate source
Plain maltodextrin is exactly what it sounds like: plain maltodextrin. It's an excellent source of carbohydrates for reasons that I explained above. It's simple and it works.
Infinit nutrition has a mixture of 3 different carbohydrates: maltodextrin, dextrose (aka. glucose), and sucrose. The maltodextrin obviously makes sense to me, but I am slightly confused to see glucose on the ingredients list. I'm not sure what it really adds. The maltodextrin will be absorbed just as fast as raw glucose, so I'm not sure why I would need to also include glucose in my nutrition. The only thing I can see it doing is creating potential for a very hypertonic solution when making a concentrated bottle, which tends to upset my stomach. The last carbohydrate, sucrose, is a dissacharide of one glucose molecule bound to a fructose molecule. Sucrose is broken down to glucose and fructose very rapidly in the stomach before it is absorbed, so again, the sucrose is adding more raw glucose to the mix. Not needed in my opinion. Moreover, fructose is a completely different monosaccharide from glucose altogether. It has it's own different receptors for absorption in the gut and is processed in the liver to make ATP (energy), which can then be shuttled to the brain and muscles. It is not as good of an energy source as glucose, which can be processed directly in the muscles. In my opinion, fructose (via sucrose) is not needed in the mixture and actually undesirable. It is often a major culprit in gastrointestinal distress during exercise. I have talked with Michael at Infinit nutriton about this, and as I understand, the reason that they add sucrose is because of some data in the literature that shows an increased carbohydrate oxidation when ingesting a mixture of glucose plus sucrose vs. plain glucose (or maltodextrin) alone. The carbohydrate oxidation is reported as being increased from ~1 g/min to ~1.25 g/min. What does this mean? It potentially means that your body could absorb about 5 kcal per minute of carbohydrate with a glucose/sucrose mixture instead of just 4 kcal per minute with glucose (or maltodextrin) alone. Over the course of an hour, this would theoretically be taking in about 300 kcal instead of 240 kcal. The key thing to understand however, is that this data is reported as increased carbohydrate oxidation, not increased glucose oxidation. The 0.25 g/min increased oxidation that they report is due to fructose oxidation, because there is fructose in the mixture via sucrose, and fructose has a different pathway for metabolism than glucose, as I have already mentioned. This fructose oxidation, in my opinion, is irrelevant and not useful during exercise. There are no performance gains to be had here. I have not seen a paper (and I don't think that I will), that reports any increased glucose oxidation over 1 g/min. If anybody has one, please send it to me.
The winner of this category: plain maltodextrin
Ease of use
Plain maltodextrin is pretty darn easy to use. It comes in powder form and it contains 4 kcal per gram. So, just figure out how many kcal you want to ingest per hour, and mix up a bottle. I have no problem concentrating a single bottle up to 5 hours. It mixes best in slighlty warm water, which can then be chilled after it is all in suspension. The major downside to plain maltodextrin however, is that it is just pure carbohydrates. It lacks one of the key three components that I mentioned are necessary in endurance exercise: electrolytes. Thus, you have to supplement electrolytes somehow. I choose to supplement them by taking Salt Stick caps. Salt Sticks are primarily sodium and potassium (which is all you need, in my opinion), but they also have a little bit of vitamin D, calcium, magnesium, and chloride. I like them because they are relatively cheap and easy to swallow. The major downside is that I have to carry a pill box. I have tried to break open the caps and mix them in my maltodextrin mixture, but it always ends up tasting way too salty and is not palletable for me.
The big seller about Infinit nutrition is that it is completely customizable. Their online system is pretty cool. You can choose levels for flavor, carbohydrate blend, calories, electrolyte blend, protein, amino acid blend, and caffeine. They put it all in one mixture for you and tell you to take 2 scoops per hour. All you have to do is mix it up and you're good to go. You need absolutely nothing else besides plain water. Michael told me I would be amazed when I saw how easily this stuff mixes into solution, and I must say, I really am. He told me that they buy some really top-shelf ingredients to produce the Infinit, and I believe him. It really just takes a few motions turning to bottle over back-and-forth to mix up even a 3-4 hour bottle. You hardly even have to shake it. No messing with warm water and then chilling it. Cold water works just fine. The only downside I can see to mixing this stuff up is that since there is protein in the powder, it foams when shaken. This is unavoidable for any mixture that contains protein, but kind of annoying in my opinion. Since I don't think that I really need the protein, I'd probably consider just leaving it out altogether. The foam can make it difficult to top off the bottle with water, or it can make it difficult out on the road to see how much solution you actually have left in your bottle and how much is just foam. Really just a minor annoyance, but something to think about.
The winner of this category: Infinit nutrition
Cost
Like I said, plain maltodextrin is dirt cheap. I buy it for $2.00 per lb at City Beverage in Winston-Salem, NC. I could get it even cheaper if I wanted to buy it in quantities greater than 5 lb at a time. The only other cost to consider in fueling with maltodextrin alone are the Salt Sticks. A bottle of 100 caps costs $20.00. A one hour serving of maltodextrin for me is 75 g, so I can get about 6 servings out of a 1 lb bag, making it about $0.33 per serving. I generally take about 2 Salt Sticks per hour, so if I add in $0.40 for the two Salt Sticks, a one hour serving of maltodextrin plus Salt Sticks cost about $0.73. If I think about it in terms of a 5 hour bike ride, that costs me about $3.65.
Infinit nutrition is pricey. My invoice says that a 25 serving bag (take one serving per hour) costs $42.95 plus $10.53 for shipping, making this product $2.14 per serving. For my 5 hour bike ride, that costs me $10.70.
The winner of this category: plain maltodextrin. Personally, I can't justify spending ~$10 on my nutrition for every long training ride. That cost can really add up over a season training for an Ironman.
Overall satisfaction
There's nothing fancy about drinking plain maltodextrin. It's essentially flavorless, and it gets pretty syrupy when heavily concentrated. Taking the last swig of warm maltodextrin syrup 5 hours into a bike ride isn't necessarily fun. On the other hand, it has NEVER caused me any gastrointestinal upset. It's plain and simple, and my body knows how to use it. It gives me the calories my body needs and I finish my rides feeling strong and ready to run. I ocassionally will mess around with adding a little bit of flavor to my maltodextrin mixture by mixing in a scoop of Crystal Light or Gatorade powder, just to give it a little bit of flavor and I think this helps a bit. I do get tired of popping Salt Stick caps though and have often wished to find a convenient way to add electrolytes to my maltodextrin mixture.
I will say this, you get what you pay for with Infinit nutrition. It's a designer product and it certainly works like one. The taste is great. You can select anything from a mild to strong flavor depending on your preferance. I chose the orange flavor and I've been happy with it (they also have lemon-lime and fruit punch). Even at the very end of a ride, I have pulled into the garage with my bike and willingly taken the last swig of Infinit nutrition out of my bottle. That says a lot, that I still have a desire to drink it at the end of 5 hours! Also, for the amount of sodium that this product has in it (I chose a sodium content per serving that was about equivalent to that of 2 Salt Sticks), you certainly can't taste it. It doesn't taste anything like when I try to mix my Salt Sticks into my maltodextrin. I don't know how they hide the saltiness, but I certainly don't notice it. Overall, I feel that the Infinit has worked just as well as my maltodextrin mixture for providing me energy during the ride. The first couple of times I used it though, I did have a little bit of gastrointestinal upset. I felt like my stomach was kind of "sloshing" around towards the end of my ride and I didn't feel quite like myself at the beginning of my run. By my third time using it for a long ride, that feeling had completely gone away. It seems that for me, there was a bit of an "adaption period". The only thing slightly different feeling about the Infinint, is that stragely, it makes be burp during the ride. It's not super often; maybe once every hour, but it's there and I'm not completely sure why. I never burp with maltodextrin mixtures. I think it might be the protein. Either way, it's not really a big invonvenience (for me at least). And finally, I'll admit that I was a little bit skeptical when Michael at Infinit nutrition told me to keep just a tad bit of protein in my custom Infinit mix because it helps to ward off hunger on long rides. I've never noticed any gnawing hunger pains during my long rides with plain maltodextrin, but generally, I am rather hungry when I get in the house after a long ride or a long brick and I sometimes have the urge to eat everything in the cuboard. After workouts using Infinit, this post-workout hunger is definitely minimized a degree and I'm generally pretty satisfied when I walk in the door. So even if protein doesn't help during the actual exercise, I suppose if you can tolerate a little bit of it, you might help to minimize some post-workout hunger.
The winner of this category: Infinit nutrition
So, it appears that I've established a "tie" between my plain maltodextrin and Infinit nutrition. So what does this mean for my training and racing? Well, I can't justify the cost of the Infinit nutrition for everyday training since my maltodextrin works just fine. So I will continue to use plain maltodextrin for long training workouts. On the other hand, for races lasting several hours or more, the convenience and ease of use of Infinit nutrition seems worth it to me. A 25 serving bag will last me a decent while if I save it just for races, and maybe a couple of pre-race workouts to get my stomach "ready" for it. I plan to use Infinit nutrition in my upcoming 140.6 (Rev3 Cedar Point).
