Are isotonic gels really isotonic?

14 messages
16/02/2010 at 12:22
Hi all, while at he TCR show on Sat, I got chatting to the dextro energy rep (while trying out the tasters of course), and I asked if their gels were isotonic like the SIS go gels I currently use. He said that was all a marketing ploy and you actually cant get an isotonic gel, and that the "isotonic" ones are just watered down and would only provide up to 15min energy opposed to the 45 from a normal gel. Of course he would say this while trying to sell me his stuff though. But it got me thinking..

The reason I switched from the powerbar gels was that they were really thick and just tasted like they needed water to wash down, whereas the SIS ones dont. But it is worrying if they aren't giving a kick for as long as I though they were.

Any thoughts on the matter would be great.

I R BABOON
16/02/2010 at 15:47
Putting my old Chemistry hat back on (and please excuse the fact that some of my descriptors may not be published in the Lancet) - also feel free to correct me if anyone knows better

Isotonic sports drinks etc contain similar sugar and salt concentrations to that in the human body. As the concentrations are similar this enables the valuable nutrients (in this case predominantly glucose) to be absorbed through osmosis more quickly into the human body. In order to get the right concentration of 15g of glucose per 250ml this automatically makes this a liquid since thats a lot of liquid to dissolve the sugar in.

In terms of gels, these are predominantly glucose syrup (85%+) so serve the purpose of packing in as much glucose as possible in a small sachet. This obviously acts as a good source of fuel but due to the massively high concentration of glucose this cannot be isotonic and absorbed as quickly. Unless of couse - as conehead says, you've figured out a way round it!
16/02/2010 at 16:40
My limited understanding is that there is an ideal concentration of sugars that your body can digest quickly... too weak and, well, you're not getting as much energy... too strong and your body needs to provide the fluid to digest it.

It always made me wonder about gels... I would need to drink the right amount of water after eating one, which as conehead says is hard to do. That's why I use sports drinks that I mix up beforehand, so I can do the measuring in my kitchen rather than when I'm caning up a hill.

However, I know from painful experience that I cannot get enough energy from Lucozade alone, so how do you balance it all up? Do more complex foods or gels/solids require less water?

Put it another way.. How do you carry a useable 500 calories (say) of food + drink on your bike?

Supplier of stinking sweaty sports clothes to the laundry industry since 2003.
16/02/2010 at 16:44
I guess I should have spoken to the mad professor too, but as it happened, I just spoke to this fool on the way out, getting some sugar for the long walk back to the car you know..

My first instinct was "he's talking crap and you cant just put isotonic on something if it isnt". damn salesman and his pitch! Well i stil didnt buy anything. Got their freebies in the goodiebag anyway!

cheers!

I R BABOON
ris
   Moderator
16/02/2010 at 17:57
high5 are now doing an isotonic version of their gels, which is great because i can't stomach sis!

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most disturbing in lycra award, 2010, 2012, 2013

21/02/2010 at 21:51
Bopomofo wrote:
How do you carry a useable 500 calories (say) of food + drink on your bike?


Easy: Soreen

Don't hate me because I'm fat
21/02/2010 at 22:52
The devils food.

I'd rather eat roadkill

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21/02/2010 at 23:10
willieverfinish wrote:
I'd rather eat roadkill


I thought it was roadkill
22/02/2010 at 17:45
A entire Soreen loaf is just under 900 cals, which is worth less than an hour of cycling. So how do you fuel for, say, a half-iron 3 hour effort.

I've managed to get it badly wrong in the past, so curious to know how many cals others eat on the bike and in what form.

Supplier of stinking sweaty sports clothes to the laundry industry since 2003.
md6
22/02/2010 at 17:55
Bopomofo wrote:
A entire Soreen loaf is just under 900 cals, which is worth less than an hour of cycling. So how do you fuel for, say, a half-iron 3 hour effort.

I've managed to get it badly wrong in the past, so curious to know how many cals others eat on the bike and in what form.


900cal/hour, really? Wow, I had it figured as between 600 and 700, i guess it depends on the effort levels but even when pushing it i didn't think it would be that high. I am going to seriously need to do some nutrition practise for Im this year...

Run hard, run fast, don't die...

22/02/2010 at 18:02
900 cals/hour. How the hell do you ride a bike. I'm lucky to burn up 5-600 calories, and even then I couldn't sustain that over a IM bike leg.

Two bottles of Gatorade (about 120 cals/bottle) + 3 Powerbar Gels (110 cals/gel) = 550 calories/hour, SO providing you can maintain that throughput, then you shouldn;t go into too much of a calorie defecit

2010: White Horse Challenge, Dragon Ride, RoW Sprint, IM UK 70.3, Eastnor Castle Middle Distance, IM UK: All boxes ticked
2011: Now to go faster. Then IronMan Wales came along, so the speedwork can wait until 2012
22/02/2010 at 19:43
Yeah, sorry, I'm just going on what the bikes at the gym tell me... but then, the maths doesn't add up at all.

Apparently, last session I averaged 258 watts over 1 hour, which is almost certainly more than I am capable of. Even so, this would be 258*3600=930kj, or around 220 calories, but the machine said 1050 cals.

Now, while I don't care about actual power output, so long as the number goes up as the months go by, it does make me wonder how much I should be eating.

Oh bloody hell, I'm confused.

Supplier of stinking sweaty sports clothes to the laundry industry since 2003.
GGB
22/02/2010 at 20:11
For shorter rides under 50 miles I usually can manage on 3 or 4 Fig Rolls and an energy drink - with a water and nuun - over 50 miles then its probably about 6 or 8 fig rolls - energy drink x 2 and a nuun along with some energy gels if need be - I messed up my HIM last year with nutrition - ran out of energy on the run -

Fig Rolls = about 60 cals each and 12.2g carbs -

Don't know if thats good bad or what but I seem to manage on that -

Ohh and quite often a few slices of the black stuff .... mmmmm

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22/02/2010 at 22:12
So, GGB, like me you had an eating strategy that didn't work.

Think I'll head over to the BCTTT forum... there's some bloke there who reckons he knows about food. Mainly Krispy Kreme donuts, I believe...

Supplier of stinking sweaty sports clothes to the laundry industry since 2003.
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