My study on postexercise glycogen recovery
 

Hi,

I've just published a study in which we are aiming to optimize postworkout nutrition for cyclists. In summary:

A mix of the sugars glucose and fructose (or sucrose aka table sugar):
- does not improve glycogen recovery in the muscle
- improves glycogen recovery in the liver
- is much easier on the stomach
- results in better rehydration
...compared to a sports drink that contains only the sugar glucose (unfortunately, a lot of commercial drinks fall in this category).

I've written an in depth article on the why, the results, and how to apply in practice:
Why Fructose and Sucrose are Beneficial for Athletes

Or you can check out my original research article:
Fructose Coingestion Does Not Accelerate Postexercise Muscle Glycogen Repletion. - PubMed - NCBI

I would love to hear your thoughts on my article & study, or any questions on sports nutrition in general!

Personally for myself I take a very different approach towards sports nutrition...All starch get converted into glucose and that's the reason why I rely mostly on starch from whole foods for my carb intake. I believe that starches is a much healthier way of getting your carbs then sugar. You can't sacrifice health for performance, there needs to be a balance... I also completely avoid simple refined sugars or refined carbs in any form. Majority of the sugars in my diet comes from whole fruits which are about 60/40 glucose to fructose ratio...I prefer foods which have more glucose then fructose that's why I eat white potatoes, squashes, oats and rye...I also refuse to accept this "nutritional dogma" that refined carbs and sports drinks made from refined sugars are necessary for performance and recovery. My personal favourite post-workout drink is a smoothie made from whey protein and banana or whey protein with some berries...My body is very efficient at burning fat for energy, and running out of glycogen or bonking is the least of my worries.

Too bad you give a link only to the abstract. The publishing of studies only behind paywalls is much to be deplored. Abstracts do not allow a researcher to assess the quality of the study and thus aren't worth nearly as much as a PDF, particularly when there is some obvious desire on the part of the original researcher to influence behavior.

What is not said in your post and abstract may be more important to us than what is said.

But other than that, we appreciate your work, interest, and post. More information is always better. I have experienced good muscle glycogen along with poor liver glycogen replenishment, which was not fun.

You just haven't gone hard enough, long enough. I went through a long apprenticeship, learning to hold the wheel of the A group on 50-100 mile rides. I never fully bonked, but I had many off-the-back experiences when my power dropped off after a couple of hours or so. It took me a while to learn what super-high GI foods would get across my stomach wall very quickly. It doesn't matter so much what you eat in your civilian life, but after long periods at LT and still 3 more hours to go, it's going to matter a lot. The "dogma" exists because nothing else works at that level. You climb in zone 4 and recover in zone 3, hour after hour.

I remember a little vignette: I was back quite a ways in the paceline when a newbie rider behind me yelled, "We're doing 30 mph! Who the heck is that woman who's pulling?" She was a friend of mine. That's how it was, and it was a gas.

WC -
...My body is very efficient at burning fat for energy, and running out of glycogen or bonking is the least of my worries...

How did you get your body to efficiently burn fat? How do you know it does?

one of my clients is a triathlete ....

she recently done a very long grueling charity cycle race in France (over a few days), and she says they were fed peanuts and jelly beans during the whole race

Through regular training and avoiding fueling with sugar...Do a search there are few different ways of doing it.

I can tell by the way my body looks when I look at myself in the mirror.;)....

True, majority of my bike rides are done at a lower to medium intensity, no more then around 55-65 VO2max with an occasional hard effort like a short hill climb or a short sprint or fighting my way through winter snow, I don't hammer hard for extended periods of time....My strength and conditioning workouts are the ones where I regularly put in max effort, but they only last 20-40 minutes per session so I don't worry about glycogen depletion and bonking. My longest bike ride to date is 104 miles.

Even though I fuel on the bike with sugar and its relatives, my body will also burn fat efficiently. That's very common among highly trained athletes, of which, for my age, I am one.

The way to get it to do that without eating a high fat, low carb diet is to train on the bike at low to moderate intensities, fasted, for periods of 1-3 hours. You'll burn through your blood sugar in less than 45 minutes. The rest of the energy has to come from metabolizing fat, that is, moving fatty acids out of your adipose tissue and into the mitochondria of your muscle cells. The way you'll know you've succeeded is that you can do that.

Getting thin has more to do with eating less than you burn, however having a diet that enables you to eat less is the trick and might be individual.

I rode a 400k in 15 hours when I was over 60. I did my first century at 18, in 7 hours, when I was eating dorm cafeteria food, on one candy bar and one orange. I didn't bonk either. Last year I did a 3 hour ride averaging 88% of my LTHR. IMO it's more about precisely how you train than it is about precisely how you eat.

When I've gone to the gym this winter, I've been lifting heavy for ~1.5 hrs. with 1 minute between sets. If I didn't use a sports drink, I'd pass out. I go through 100-150 calories of sports drink in a session like that. I'd have to dial it way back to avoid ingesting those calories, which I think would actually result in a worse CI/CO balance. As they say, fat burns in a carbohydrate fire.

How many feet of climbing in those 104 miles?

I live in rolling terrain, no big mountains around here, nothing too extreme. I can do majority of hills in my area with 65-70 gear inches on my FG and SS bikes.

I think ''nutrional dogma'' that refined sugars are inherently unhealthy.

Sugar is nothing else than a source of energy. If that energy fits with the energy requirements of the consumer, then it's perfectly fine. Our lab has done research on what cyclists eat during Tour the France. All they care about is meeting their energy requirements. However, for a an individual with little physical activity, sugar often results in overconsumption, and so is bad that context.

The scientific data though strongly suggests that for optimal endurance performance and recovery, sugar is the way to go. In the same manner, all the data suggests that when people run out of glycogen, they perform considerable worse. (for both statements, a mimimum duration and exercise intensity is required ofcourse, perhaps you have shorter intenser training sessions where glycogen/additional intake of sugar is of less influence).

You are absolutely free in your believes and practices. I'm just sharing my data and the current scientific data. Perhaps experiment with our suggestions, hopefully you get something out of it. And if you don't like it, stop doing it. :)

I wish I could share the whole article. Unfortunately, you are not allowed to share it once it's accepted in a scientific journal. Free, open access of journals is slowly increasing though.
That's why I also write about my research on my own blog, to make it available for a larger audience.

I appreciate that. It's good to hear that information is becoming more widely available. I do notice the occasional PDF.

I encourage you to post here on other topics. Your blog post about rep ranges might get some attention. Anecdotally, I've lifted to failure using sets of 30 and sets down to 4, and had similar gains in thigh size from them. Sets of 4 is quicker though!

Along that line, I'm interested in weight training for force production vs. endurance for endurance sports. I notice that Norwegian researchers have been using sets down to 4 for pre-comp and comp period weight training:
In-season strength maintenance training increases well-trained cyclists' performance. - PubMed - NCBI
http://www.hokksund-rehab.no/filarki...ES_CYCLING.pdf
It would be interesting to compare results between using sets of 30 and sets of 4, both to failure.

I also read your posts on post-exercise protein. Lately I've also been using pre-exercise protein as studied here:
Timing of amino acid-carbohydrate ingestion alters anabolic response of muscle to resistance exercise | Endocrinology and Metabolism
for both resistance and endurance training. My anecdotal response has been positive.

I'm 70 and my protein requirements, judging from leg soreness, seem to be greater than the usual estimate:
Contemporary Issues in Protein Requirements and Consumption for Resistance Trained Athletes