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Discussion Starter · #1 ·
I dislike paying very high prices for tubs of very cheap chemicals, dressed up in packaging and plastic. So, like many, I've decided to make my own drink. The main ingredients, fructose and maltodextrin, can be purchased very cheaply and the electrolyte and flavour bit are just salt, potassium chloride and citric acid. I.e. fruit juice. The only question I have concerns tonicity or concentration. There are many excellent articles online about accelerated absorbtion of cabohydrates with varying proportions of maltodextrin and fructose, but the best one I can find appears to suggest roughly 7% of each. Doesn't that mean 14% overall? Other stuff I've read seems to suggest 11% is as high as you should go.

Anyone have any insight into this?

Useful articles;

http://journals.lww.com/acsm-msse/A...f_Combined_Ingestion_of_Maltodextrins.13.aspx

http://jap.physiology.org/content/104/6/1709.full

http://www.ncbi.nlm.nih.gov/pubmed/21071509

http://www.cptips.com/hmdesnk.htm
 

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I've been making my own drinks for about the past year and my best suggestion to you in figuring out the concentration levels is to cheat a bit and look at some of the labels on the more commonly used drinks out there.
I'd suggest that as you add fructose to your mix that you may want to consider the effects fructose has on creating metabolic syndrome. While ingesting fructose during exercise may attenuate it's negative effects, the studies you posted are short term and do not provide for the consideration of metabolic syndrome.
Here's an article on fructose and metabolic syndrome:
http://edrv.endojournals.org/cgi/content/full/30/1/96
and one from the ACSM on the issue:
http://journals.lww.com/acsm-csmr/Abstract/2010/07000/Fructose,_Exercise,_and_Health.15.aspx

I'm still a supporter of adding some fructose to a mix, but the question becomes at what level is it safe? As more research is needed, in my opinion, to determine what are safe levels during exercise, I am keeping my fructose levels low in comparison to the ones used in the studies that you posted. Insulin insensitivity and liver damage are not to be taken lightly.
 

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Discussion Starter · #4 ·
Now calm down, iwanttolookatpics; I borrowed your mother's iPad.

But wow, Whambat, a man after my own heart! I'm a biochemist but have been out of the field for some time, so the material you've sent really interests me. I had not idea of the unique metabolic pathway of fructose (no negative feedback mechanism for fructokinase! What?!) and its potential to deplete phosphate, activate AMP deaminase and increase uric acid levels!

I was, as you suggest, hoping to mimic label information on drinks that have worked for me, like Gu Brew, etc, but so far have not found any absolute measurements, only ingredients listed in order of content. Do you have any you could share?
 

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Whambat - Great to see others interested in this stuff. Fructose consumption on the scale seen in this country has been i.d.'d as a potential major health problem. Athletes are not immune to this, particularly when the deleterious effects are from the degradation products. Look at your food labels and you will see a TON of fructose in your high carb diets. That means a ton of the degradation products.

There is evidence that fructose is really useful to endurance athletes but, as always, be careful how you use it.

(Incidentally, also good to see another Neti pot user.)

Larry
 

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Discussion Starter · #6 ·
I think we need to be careful how we interpret this and stay objective (I don't mean to suggest anyone isn't being objective...). There are many complex interacting factors described and it might be inappropriate to start suggesting fructose is 'bad' per se. In the land of the layman, things get labelled in a very basic way and assume all kinds of strange connotations almost overnight. Just look at Britney Spears!

But seriously, you could argue from this article that if you are very active and consume large amounts of high quality foods and vitamin C in addition to fructose, a great deal of the risk factors and negative things mentioned in the article pretty much don't apply to you. They seem to be mainly talking about epidemiology across large populations of lard assed Americans ladling corn syrup on their pancakes before they settle on the couch for the day and retrieve the remote from their ass crack. That profile doesn't fit for most XC racers on this forum.

Fructose has been a huge part of our diet and probably most other mammals, for a very, very long time, from fruits and veggies. I find it hard to imagine that it is not metabolically dealt with perfectly well in active, healthy individuals with balanced diets when taken in 'normal' dose ranges. Of course, you might be able to change things if you chug a gallon of super high fructose drink every day as part of your training diet, but all things in moderation...
 

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Sugars have been implicated in health problems for a long time. Linus Pauling preached it decades ago. The media just never talked about it. Fructose looks suspicously like one of the bad actors.

There is nothing inherently healthy about racing bicycles or participating in any competitive sport. There is no reason to believe it enhances general health more so than other, non-competitive activities. In fact, it carries some risk factors such as muscle imbalances and, quite possibly, the high carb diet the participants use. (And, of course, there are the crashes.)

Larry
 

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Discussion Starter · #11 ·
Ah-ha! Now I think we start to reveal the crux of the issue. It's only when you start digging (and thanks very much for digging) that you start to find how and where sports drinks manufacturers are obviously trying to protect their IP and therefore their market;

"17 grams of carbohydrates in a proprietary glucose-to-fructose blend that has been found to improve endurance performance by 8 percent"

So we still don't *really* know nutritional composition from an absolute perspective, just relative, as we don't know what other carbohydrates make up the 17 grams. All we need is a straightforward list of ingredients and amounts per 100g.
 

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The nutrition side is fairly easy to play with and dial in. 17 grams 2:1 is easy. That would be 11.3 grams glucose and 5.7 grams fructose. You can look up labels by weight or measurement to get to that number. Sucrose (table sugar) is 50:50 glucose: fructose so you could also use 2 parts sucrose and 1 part glucose to get to the same ratio. Or maltodextrin digests as glucose so you can do 2 parts maltodextrin to one part fructose. Or you could decide that you want half the fructose amount and do 4:1. All easy math.
edit: also, dextrose = glucose

It's the flavor side I've run into problems, well other than just using Koolaide for flavor. The big companies hire flavor companies and "flavorists" to adjust the "natural flavors" to make it taste the way it does. And, natural flavors are not so naturally produced, it's not like spices. A whole third-party industry is developed around making drinks and manufactured food taste they way they do.
I'm just not that into the artificial flavoring of Koolaide in something I am going to consume for hours 5-7 times a week. But, I have not had good luck with the natural flavor powders I've found, either the taste like nothing or they taste like fruit with a soapy aftertaste.
 
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