Monday, September 04, 2006

The sugar source and carb intake for racing.

I still haven't figured out the right intake of carbs during a race.

Two issues that are still up in the air for me are:

1. # of grams/carbs per hour that I can
A) absorb into my system w/o getting bloated
B) keep me from bonking

2. The form factor of the carbs
A) drink vs gel or combination.
B) carb source: blend of sugars vs one kind of sugar, which ones

-Also could drinking too much water combined with the energy drink have contributed to the bloating?

A few weeks ago I had been alternating plain hammer gels and gatorade and totally bloated out and was really sick to my stomach afer 1.5hrs of racing at high intensity.

The last two race simulations I ran 1.5 scoops of HEED/20oz bottle and strived for 1 bottle an hour. Last week I was riding for 2hrs 8minutes. And right towards the end I was starting to get that bloated feeling where everything tastes sickly sweet. And one of HEED's claims to fame is that it isn't as syrupy/sweet as other drinks.

This past weekend I ran the same concentrations but rode about 2hrs 45 minutes at high intensity. Again around the 2nd hour I started to get that bloated feeling and couldn't drink as much as I should have. I finished the first bottle in 1hr but didn't finish the second bottle until around 2:20 or 2:30. And was definitely getting that bloated feeling and sickly sweet aftertaste from almost anything I ate with a hint of sugar for hours afterwards.

This past weekend I also ate bigtime 3 hrs before the ride and had about 250 grams of carbs. The goal had been 300g. This is based on the guideline of 5grams carbs/kg of body weight 3-4 hours prior to an event.

1.5scoops Heed = about 37g of carbs. Most guidlines say that you should shoot for 30-60grams of carbs/hour. However there is a maximum that can be absorbed into your system and emptied from your stomach. If you go over this threshold bloating and that sickly sweet feeling can happen. Some places I've read that the limit is 50g/hr. In the September 2006 Issue of Bicycling (the USA today of cycling mags) there is a decent article on sugars and they are saying 1.0g/minute to 1.1.

I read with great interest the few paragraphs discussing that products with sugar BLENDS (combination of glucose, sucrose and/or fructose) meaning where the carbs come from a variety of sources and not just one can allow cyclists to reach oxidation levesl of 1.5g/minute to 1.7g/minute. But most intersting to me was that they said that subjects did not complain of stomach upset with sugar mixtures but had some trouble with glucose or maltodextrin alone.

HEED's sugar source is Maltodextrin only . Maltodextrin is claimed to be better than fructose or sucrose because it is more complex. But the thing is it's a single sugar source. Hammer gel is also just maltodextrin. I've read some stuff that said during high intensity exercise that complex carbs aren't a real advantage over simple stuff.

I originally thought Gatorade was a single source (Sucrose) but it is sucrose and dextrose so it is a blend. The New gatorade Endurance is the same as Gatorade but with more sodium and additional electrolytes

This article found higher absorbtion rates with glucose+fructose and glucose+sucrose mixtures. One study showed a 2:1 mixture of maltodextrin + fructose yielded 1.5grams/minute of oxidation. Another blend of glucose, sucrose and fructose showed 1.7g/minute.

So the question for me is:
Is it the single source of sugar in the HEED / Hammergels that is making me bloated, or am I exceeding the upper threshold for amount of carbs/hour that I can absorb/hour or is it both?

It looked like from this past weekend that I took in 37g of carbs the first hour, 3/4bottle in the 2nd hour for around 27-30g/hour. This seems to be on the low end of the 30-60grams/hour and well under the 1gram/minute absorbtion rate. That 1.7g/minute absorption they are saying for some sugar blends comes out to be 102g/hr.

One thing that isn't really qualified is the intensity at which people are riding when performing these measurements. A century pace is different than mountain bike race pace.

So two things I need to try.
1) drop the concentration of HEED down to 1scoop/ bottle which equates to 25g. Shoot for 1 bottle an hour.
*Make sure to have eaten similarly 3hrs before with very high carb intake.
-observe level of bloating and the sensation of sickly sweet aftertaste after event/race sim.
-observe energy level while racing and if I'm bonking or getting close.

2) Try a sugar blend product such as power gel or the power bar drink which have a sugar blend of Maltodextrin and fructose. I've used the power bar drink before and can handle the taste. But I can't remember if I raced with it or did a race sim with it. Retry regular Gatorade but DO NOT alternate it with gels.

I'm glad I'm focusing on this issue so that I can work it out and be confident in the solution for race day. But it's disconcerting to not have it figured out and dialed.

One positive byproduct from that last race and almost puking from sugar overload is that I haven't been craving desserts in the least. Though the brownies at the potluck we went to last night looked good. But the thought of everything else from icecream to soda makes my stomach turn. I guess it's sort of like in college when you threw up from screwdrivers or tequilla and never wanted to drink the stuff again.

Speaking of which I've only had one beer in like 5 weeks and it was only a small cup. That seems wrong in a way.


At 1:26 PM, Blogger Norm said...

This weekend I found something I quite liked...

This is in a 24 ounce water bottle:

-1 scoop orange Gatorade
-scoop plain maltodextrin
-3/4 scoop chocolate whey protein
-1/3 tsp salt

Mix & go. The maltodextrin mixes poorly at first but gets there eventually. The orange and chocolate flavors actually taste good, and the PP and maltodextrin give it a greamy taste which is nicer than the acidic taste of many sports drinks.

Never had a problem keeping it down while doing hill repeats this weekend. Not race intensity by any means. But a decent pace for 2 hours with no problems.

Did a similar mix the day before with Accelerade instead of gatorade for 3 hours. Used vanilla soy PP which wasn't nearly as good. And the Accelerade was too weak to do much to effect the flavor.


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