32GI

[Spinmeister]

hey gents, i found this interesting article on a international site, from a few days ago, which actually favors low gi as opposed to high gi, food for though maybe there is a lot to what the 32gi guys are saying.

 

 

 

Toolbox: ?Low?-grade Rocket Fuel?

 

Tuesday, April 13, 2010 6:06:59 AM PT

 

 

 

by Dr. Stephen Cheung, Ph.D.

 

 

 

   Nothing is worse than meeting ?the man with the hammer? in the midst of a ride or a race. An essential part of race-day preparation is pre-race nutrition, and the timing and content of what you eat can have a huge impact on your actual performance. We know that it is essential to keep our fuel supply topped up during the ride, but what should we be eating before heading to the start line?

 

 

 

People Get Ready?

 

It?s getting to the heart of the cycling season, which means that our big events that we?re looking forward to or peaking for are coming up very rapidly. To achieve our peak performance on the big day, it means that as little as possible should be left to chance. As we have written before, it pays off to do your pre-race homework by tactically preparing for the possible race situations. This includes both knowing the course (with such tools as Google Earth, there really is no excuse for not at least knowing the general overview) and also the way the race might play out. It should be obvious that your equipment should be tuned and running perfectly too. Of course, all of these things should be practiced ahead of time so that there are no surprises on race day.

 

 

 

The other important aspect of race preparation is physiological. One aspect of physical preparation involves doing the proper warmup for what efforts you might be facing. The other aspect is that you should ensure that your body is fueled properly for the race both in the days before and on race day itself.

 

 

 

The Glycemic Index

 

One concept that has become popular in nutrition is the idea of Glycemic Index (GI). Foods may have the same carbohydrate content in terms of total grams or calories. However, the foods may have dramatically different effects on your blood glucose levels due to the different carbohydrate makeup eliciting different effects on your insulin and glucagon (the two main hormones that regulate carbohydrate storage and release, respectively).

 

 

 

In simple terms, low glycemic foods are thought to enter the bloodstream more gradually and elicit a lower insulin response, while high glycemic index foods are felt to enter the bloodstream rapidly, resulting in a high spike in blood sugar and resultant spike in insulin response. We have probably all felt this type of reaction when we are starving and grab a sugary treat or candy bar. We feel great for a little bit, but then seem to crash and be even more tired and starved a short while later. Not surprisingly then, pure glucose forms the upper ceiling for the GI ? ranking at a value of 100 with every other food assigned a score relative to this.

 

 

 

Glycemic Index Before Racing?

 

Assuming your nutritional plans are going well and you are properly hydrated, the final question in the hour or so before your event begins is whether you should be eating anything, and if so is there a preferred food? Should you aim for a high GI food in search of that larger blood glucose availability, or is a low GI food better by giving you more gradual and sustained energy?

 

 

 

This question was the basis for a 2010 study by a UK research group (Moore et al. 2010), where they tested a low versus high GI intake 45 minutes before a 40 km TT. Some study particulars:

 

 

 

?  Ten male cyclists who logged an average of 150 km per week participated, with a mean VO2max of 58.2 mL/kg/min.

 

 

 

?  One of the main goals of the study was to maximize ?ecological validity,? otherwise known as ?real world relevance.? Therefore, the researchers chose a 40 km TT in the lab using a Velotron ergometer, with the trials occurring at least seven days apart and at the same time of the day to minimize training effect or influences from time of day.

 

 

 

?  To standardize diet, subjects ate similar meals for two days prior to each trial.

 

 

 

?  45 minutes before each test, subjects were given a standard meal of 1 g of carbohydrate per kilogram body weight. This was mainly in the form of dry cereal (e.g. corn flakes for high GI = 72, bran flakes for low GI = 30) with semi-skimmed milk. The calories of the two meals were a bit different, with 386 and 422 kcal for High and Low, respectively, for a 70 kg subject.

 

 

 

?  During the TT, blood samples were collected and analyzed for blood glucose, lactate, insulin, free fatty acids, and triglycerides.

 

 

 

?  Expired air was collected and sampled for oxygen uptake and carbon dioxide production in order to calculate energy expenditure and fuel usage rates.

 

 

 

Go High or Go Low?

 

Overall, the study was quite well designed and controlled. There certainly is an increased trend to using time trial efforts in scientific research rather than the traditional test of riding at a constant effort until you voluntarily quit or stop for some other reason. One of my very first scientific papers, back in 1995, demonstrated the high variability in response to a set workload to exhaustion (McLellan et al. 1995). This means that any manipulation that is tested using such a protocol will need to have a huge effect to be seen statistically.

 

 

 

Furthermore, the measurement of fuel use and blood allowed the researchers to explore the mechanisms underlying any observed changes, rather just simply describing a change. Summary of the results include:

 

 

 

?  Blood glucose levels spiked much higher 45 min after feeding with the High GI meal, rising from a baseline of 4.5 mmol to about 7.0 mmol (normally, blood glucose is very tightly regulated between 4-6 mmol). With the Low GI meal, blood glucose rose slightly from 4.5 to 5.5 mmol. Blood glucose dropped rapidly from the start of the TT, reaching a stable level between 4.5-5.0 mmol within 20 min for both conditions.

 

 

 

?  In response to the blood glucose spike with the High GI meal, blood insulin also was much higher than with the Low GI meal.

 

 

 

?  The arguably most important result was also the strangest one. The Low GI TT was significantly faster than the High GI. What was strange was the very slow time in both conditions, of 93 +/-8 min and 96 +/- 7 min, respectively. This was well below what would be expected of fit cyclists, and is closer to an extremely slow touring pace. Considering that they were working at >3 L/min work rate (70+% VO2max), I can only assume that this was a typo and that they meant 63 and 66 min?

 

 

 

?  Respiratory Exchange Ratio (RER), and indicator of what fuel is being used by the body, was significantly higher with the Low GI trial. This suggests that a greater use of carbohydrates was occurring. At the same time, fat oxidation seemed to be lower with the Low GI trial. This was quite different from their initial expectations, as it was hypothesized that the greater blood glucose levels with High GI feeding would spur a greater reliance on carbohydrates. From the data, the authors speculated that the opposite was actually true ? namely, the steadier release of carbohydrates into the bloodstream with Low GI permitted a greater reliance on carbohydrates and potentially a sparing of muscle and liver glycogen.

 

 

 

?  Interestingly, despite the faster speed and finishing time with the Low GI condition, subjective ratings of perceived exertion (RPE) was significantly lower than with the High GI trial. Again, this lower perception of effort may be due to the more gradual release of carbohydrates from the meal preserving glycogen stores and minimizing physiological feedback of fatigue.

 

 

 

Summary

 

Sports nutrition is very nuanced and not a simple matter of ?a calorie is a calorie is a calorie.? Other studies have looked at questions such as how much to eat at particular times prior to competition. This study suggests that, beyond straight numbers, the nature of what you eat is important too.

 

 

 

In the scenario of a fairly intense effort such as a long (>20 km) TT, this study suggests that a small, low glycemic index meal, may be a better pre-event snack than a high glycemic source containing lots of simple sugars. Interestingly, this conclusion is backed up not just by the physiological data, but also by the perceptual data of a lower sensation of effort despite a higher workload. Note that many sports drinks or gels tend to be high GI, so they may not be the best options despite their convenience.

 

 

 

The real take-home message is that, like trying out different tires, wheels, or other equipment before a race to pick the best combination, it is equally important to try out different pre-race eating strategies in practice before your main competition. Try out different foods prior to training, and keep careful notes of both how your stomach fared with digestion and also how you felt during the ride itself. Eventually, you should be able to settle on your own special rocket fuel.

 

 

 

Have fun and ride safe!

 

 

 

References

 

McLellan TM, SS Cheung, I Jacobs. Variability of time to exhaustion during submaximal exercise. Can J Appl Physiol. 20:39-51, 1995.

 

 

 

Moore LJS, AW Midgley, S Thurlow, G Thomas, LR McNaughton. Effect of the glycaemic index of a pre-exercise meal on metabolism and cycling time trial performance. J Sci Med Sport. 13:182-188, 2010

[An3]

I am a type 1 diabetic. I've had good results with Heed but tried Perpetuem today during 75km MTB race. Not great results - had to inject insulin 3 times. BG didn't want to go below 15. I'll try this stuff - for sure.

[AndreZA]

Mampara is one of the 'unofficial Hub 32gi sample testing' athletes!

 

Looking forward to his note and feedback.

 

 

 

 

 

 

Not really but I must say I like this stuff. Okay I've just done one ride with it and I felt fine. It could a number of things. I had a nice bowl of pasta carbonara (sp?)the night before and I had a very good night's rest.

 

 

 

I purchased the orange and it tastes really good. Not sweet when you drink but the aftertaste is sweetish and just stays in you mouth the whole time keeping it nice refreshed.

 

 

 

My bottles are 650ml o I used 43gr of powder and it is perfect strength. On this 90km loop of mine I always eat an energy bar at 30km. At 60km I usually stop at a garage and just have something again and then I ride home. This time I did the loop in reverse and skipped all the eats inbetween. I was fine all the way home and I did it at an 2km/h increase in speed.

 

 

 

Was it the drink or all the other factors, I don't know. I will try it again this weekend on my 130km ride.

[wolffm]

Hi Mampara

 

 

 

Good to hear you had a good ride.

 

Because your energy levels are stabilised you wont feel hungry on a ride, I have done 7 hour rides without taking in any meals at all.

 

I prefer peach by the way ;-)

 

 

 

Anyway keep us posted, and for any hubbers trying the drink please note we have a 32GI facebook site where you can write any feedback about the product, and see what others have to say.

 

 

 

Something of importance and it demonstrates our faith in the product, is that if you are no satisfied with the product we offer a 30 day money back guarantee on the unused contents.

 

 

 

all the best

 

M

[Woofie]

Hi Mampara

 

 

 

Good to hear you had a good ride.

 

Because your energy levels are stabilised you wont feel hungry on a ride' date=' I have done 7 hour rides without taking in any meals at all.

 

I prefer peach by the way ;-)

 

 

 

Anyway keep us posted, and for any hubbers trying the drink please note we have a 32GI facebook site where you can write any feedback about the product, and see what others have to say.

 

 

 

Something of importance and it demonstrates our faith in the product, is that if you are no satisfied with the product we offer a 30 day money back guarantee on the unused contents.

 

 

 

all the best

 

M

 

[/quote']

 

 

 

What about some sample packs for people on the hub?

[anthemboy]

I tried it 3 times this past weekend.  Worked ok on a short training ride on Friday afternoon.  Saturday I used 2 bottles during XC training.  Did not feel well towards the end.  Made me feel feverish, put me on a buzz. 

 

Did the same on Sunday and took one bottle of 32GI and another of Vitargo.  Got halve way with the 32 GI bottle and again did not feel well.  Went back to Vitargo and felt fine again.

 

Will try it again during the next week or 2 but so far, not for me thanks!

[wolffm]

Thanks for the feedback.

 

Let me know next time you try, thats a first from hundreds of users, there is nothing in there that would give bad side effects at all. What did you eat the night and days before training as a matter of interest?

[AndreZA]

Wolffm, I think there is a misprint on the nutritional fact sheet. The kilojoules is less then the calories and it is normally the other way around. 1cal = 4.2kj

[anthemboy]

Nothing out of the ordinary.  Normal cereal breakfast with multivits etc.  Just a banana or two during the ride.  Was not a long session, but fairly hard.

 

It says it will provide sustained energy for 2 hours per helping.  Should you then alternate with water for hydration and not exceed the one helping per 2hours.  I need plenty of fluids since I dehydrate easily. 

 

I used 2 bottles of 32GI during the 2hour training session.

[Flemish Lion]

7.5 hour ride' date=' 2.5 bottles of energy drink, NO FOOD, NO GELS, NO anything, my energy levels were so sustained, I had to force down my protein at the end. This stuff cant be legal........ anyone else there used it, I think this product is going to fly.[/quote']

 

 

 

This add could potentially be DANGEROUS for the average Joe cyclist

 

 

 

But how cool would this be... complete the 2010 Double Century without a back-up vehicle!! All you need is an extra bottle in your back pocket...

 

 

 

A DC in 7,5 hours is riding at a moderate pace - would love to see anyone complete it on energy drink only though

[wolffm]

Hi Anthem, I see the issue:

 

 

 

Eating a banana during a ride, which has an average GI of about 50 to 67 depending on how ripe the banana is, will affect your sugar levels significantly. Taking in 32Gi which has a glycemic index of 32 is pretty much negated when u introduce the banana, as you change your levels considerably. When utilising a low Gi drink like 32Gi there is NO need to eat especially on a short 2 hour session. It stabilises your energy levels and gives u the correct amount of glucose. Our intensity test where a professional athlete time trialled at 90%-100% of max, performed at this pace for a period of 2hours and 25 minutes. You need to remember that when going with a low GI energy drink, you can totally negate its effects by taking in a high GI substance. What you take in will set the precedent for your journey. Starting with anything high GI will require top ups continuously. Once you took the banana in, I would have recommended taking in a higher GI product for the balance of your training. If you need to take in food, then ensure the glycemic load is low as well, so for example, sugar free oat cookies, low GI seed bread with peanut butter, there are many more, but just some ideas.

 

 

 

 

 

You are correct in that one serving is = 2 hours. You need to take in at least 250 to 500ml, at least 30 minutes before beginning your session. As you want the effects of the drink to start immediately, and then you should be completing a 500ml to 750ml bottle within 2 hours. A 2 hour training session on 32Gi is a very short session, its far more beneficial on the longer rides, 3 hours and up, unless you are going high intensity on the short rides.

 

 

 

From a nutritional point of view, its not a wise idea to take in your multivitamins pre-training, rather take them in post training with your recovery meal, as any additional minerals or vitamins taken in will impact your system significantly when under stress, remember these are only supplements yet your body needs to absorb and process and its not a good idea during a session.

 

Additional zinc as an example can lead to nausea in some people under certain conditions. I wont go into all the aspects, just an example, and some useful information.

 

 

 

all the best

 

M

['Dale]

I plan to do the Double Century for the 1st time...

 

This product will definitely be worth an experiment.

 

 

 

Wanna make sure that it does not harm the bod and the system in any form whatsoever.

 

 

 

 

 

Mampara,thanx for the feedback.

 

The 130 km cycle will be a good test.

 

 

 

[wolffm]

Guys remember 32Gi is "Child Friendly", its very safe and no nonsense.

[madcyclist]

Where can I get 32GI in Australia? If not, can you mail to Australia?

[wolffm]

PROMOTIONAL COMPETITION:

 

 

 

FROM Facebook 32GI

 

 

 

32GI COMPETITION: The first 10 people that purchase a bottle of 32Gi? from Dis-Chem or Tony Impey from today onwards, and show us proof of purchase will get R40 back per a bottle from 32Gi?. Race is on...................

[Gsxr]

Wanted to buy at Dischem Retail crossing yesterday but the guy there had no idea what I was talking about. Anyone bought from Dischem?