livedarklions

I've gone back to eating every 50 miles or so, but when I was doing the 100 mile rides last year, I certainly didn't notice any muscle wasting. I didn't measure it, but I did seem to have less body fat. My power seemed stronger than ever. I don't do it now because it just isn't much fun to do that once a week. The mid-ride lunch is a really nice part of my week.

prj71

50+ miles before I touch drink or food.

25 miles is nothing.

MoAlpha

I dunno, man. I learned about gluconeogenesis in college biochem back in, like, 1978. Lactate's not strictly a fuel because it takes energy to convert back to glucose.

Hypertrophy, as applied to muscle, just means bulking up from exercise. Glycogen doesn't affect muscle volume appreciably as far as I know, but blood flow does.

50PlusCycling

The power you are able to generate depends more on what you eat the day before your ride than during the ride itself. It usually takes me about 20 miles just to get fully warmed up. I have bonked on long rides (80 to 150 miles), but these were due to not loading up the day and evening the day before, and no matter how much I eat during the ride, I cannot generate the energy I would had I eaten properly before the ride. A hard bonk during a long ride is a miserable experience. If you are going to do a very long ride, starting eating from lunch time the day before, eat gradually until an hour or so before bed. Rice or pasta, with some kind of fat (butter, oil, etc) and some protein, eaten every 20 minutes or half an hour will distribute the food evenly in your digestive tract, allowing your body to extract nutrients more effectively. Race horses are fed 5 times a day for this reason.

ThermionicScott 

ISTR your muscles hold 4 grams of water for every gram of glycogen, so you're largely seeing water when that's topped off.

But that's not the main driver of growth or we'd all look swole after a Mountain Dew.

PeteHski

Ah okay. I just think of carb loading as something some people do a couple of days before a big event in an effort to top up their glycogen stores. I've never really associated it with carb deprivation beforehand.

livedarklions

Yes, I know what hypertrophy is, I'm also aware there's no consensus on its evolutionary purpose. I just wonder if, since about 80% of glycogen is stored in skeletal muscles, whether some of that muscle growth is actually greater storage capacity.

Better update your view of lactate-- it's a major fuel unto itself for heart and skeletal muscles: https://news.berkeley.edu/2018/05/23...oison-to-cure/

livedarklions

That doesn't make sense, no matter how much Mountain Dew you drink, your body has limited capability to store glycogen. I'm not suggesting sucrose/fructose intake stimulates muscle growth. Don't hypertrophied muscles have the ability to hold more water than smaller?

There's obviously some adaptive reason we have evolved to grow muscles that are used heavily and no one reason seems to explain it. I think the logic may be pulling towards metabolic issues, glycogen and perhaps lactate among them.

GhostRider62

Are you arguing that gluconeogenesis does not exist or isn't a common problem for under nourished endurance athletes?

On an individual basis, it is not easy but one can predict when the tank hits E.

RER differences at the same relative workload vary enormously from individual to individual. However, the ability to burn fat at sub threshold power levels is highly trainable and one's ability to ride longer without eating can be improved. A few years ago, I could do a moderately hilly 200K in 8 hours on just water. Today, I would struggle with 40 miles in the hills on water.

I have always wondered the extent to which training increase glycogen storage and where it is stored. But, I am sure the ability to store more is related to training but no refs

livedarklions

Read the quote a bit better. I was explicit that what I found hilarious was the notion that this was so uniform that you could predict knowing nothing other than number of miles and hours. I've been arguing with a guy who claimed that my "numbers didn't add up", which assumes he doesn't have to know anything about me or my conditioning to calculate where I'm going to hit E. I never claimed that I was born able to ride that far without eating or that if I stopped working out, I would still be able to do it. As a matter of fact, I had an illness that pretty much stopped me from any strenuous workouts over the fall and most of the winter last year, and my endurance was definitely reduced at the beginning of the spring for a lot of reasons. I haven't attempted a fasting century this year, opting instead for a 50 mile break on the many centuries I did ride last spring, summer and fall. You and I agree totally.

My last lines are about how the science is still developing in this area, and I think it's only now starting to understand how conditioning may work to increase endurance. In hindsight, I don't think I expressed that clearly or well.

GhostRider62

Why were you arguing with someone who knows nothing?

You had said earlier something to the effect that there are very few who have ridden 300 miles in 24 hours but there are at least 2 or 3 on this thread who have done more miles than that in 24 hours, many times.

Subjecting one's E level to testing on the road isn't fun but something I have done. Your statements about miles and eating are very believable. I think I stated that I have ridden 8 hour 200K brevets in hilly terrain on only water. I also rode 453 Km in 15 hours on 1 banana and two gels, clearly not optimal but I had no food except my own body fat. I lost 5 pounds of fat in 1230 km over 2 days. Let's see if that math adds up for your friend.

https://www.sciencedirect.com/scienc...26049515003340

MoAlpha

Apparently, glycogen storage is trainable if that's what you were wondering about and not the quantitative extent. Here's a nice review on it.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6019055/

Glycogen is only stored in skeletal muscle and liver, as far as I know.

livedarklions

Because he picked a fight with me by claiming my posts were implausible. I don't know about you, but I really don't care for implications that I'm somehow lying. Also, I find the subject interesting, and it's been interesting reading other people's take on why he's wrong..

I think 300 miles in 24 hours is rare. I also think that the people attracted to this thread are going to be people who do rare things, you perhaps more than anyone else on this thread. I don't think I could tolerate that just for lack of sleep, so I'm damn impressed by people who can. If I recall, I mentioned that because I thought the OP should start a thread in the endurance forum. Also, keep in mind OP mentioned the T2 diabetes, so that may be a complicating factor that other endurance riders have coped with over such long rides.

GhostRider62

When I read it, it seemed to me that he was just pulling garbage off the internet

At 60% of VO2 max, riders need from 10-45% of the energy from glycogen depending on their body and training. This probably corresponds to 75% of FTP for many riders. Very damned few riders if any can maintain that level for 24 hours. IIRC, the 24 hour world champion Christophe Strasser averaged about 260 watts over 24 hours but his FTP was around 415 watts and Marko Baloh averages similar percentages. I can only do 65% of FTP for longish events or around 50% of VO2 max but I drop off the cliff at 14-15 hours into the pits of hell. This power would get me like 10-11 hour double century pace on flat roads. At that moderate pace, most of the energy is coming from fat; however, failure to eat sufficient carbs is very bad of course. When I see posters saying stuff like you need 700 calories per hour and the majoring of it comes from carbs/glycogen within the context of a long endurance event/ride, they are just guessing or reading too much gatorade funded research.

Total calories per hour at 20 mph varies enormously. Route? Rider weight? Tires? Aerodynamics? Metabolic efficiency? Wind? And others. The percentage of fat/glycogen also varies from rider to rider....see the FASTER study that I linked. The sugar burners were only 56% fat at 60% VO2 max whereas the fat burners were close to 90% at 60% VO2 max. So, even if we use the inflated 650 calories per hour, that is only 65 calories from glycogen. Going by my numbers, 60% is around 220 watts and that gets me almost 22 mph, which is my cruising speed on long brevets where I typically eat 100-150 cals/hour unless someone makes homemade banana nut bread then it is lights out. Again, what you wrote is more than believable.

ThermionicScott 

It was an attempt at humor, forget it.

livedarklions

I about said as much in my first reply to him, then he doubled down.

You obviously know more about it than I ever will, so I appreciate what you're posting here.

Getting back to the OP, I'm really not saying that there's a benefit to riding while fasting, just that it's doable at some pretty long distances if you train up to it. Do you think there's any benefit to it other than maybe some faster fat burning?

GhostRider62

Yes. 100% It helps with AMPK and thus PGC-1α to stimulate mitochondria biogenesis.

For me, if I eat dinner at 5:30pm and ride in the morning without eating, I am fasting. Some call that IM.

rsbob 

The OP stated he has type 2 diabetes. Are you trying to kill him or just is this just about you?

Branko D

I could and sometimes do eat less on long tempo rides, but eating during a ride has only ever improved my performance during that ride; sure, if I'm going easy at 60% then I don't really feel much of a need for eating anything, but the harder (and longer) the effort is, the more pressing the need to eat correctly is.

I can do about 200W (which is about 75% of my guesstimated FTP of 265-270W), expending about 720 kcal/hr plus BMR without eating anything for about three and a half hours, but I can feel it biting by the end and I'd probably let up the power by the end if I wasn't nearing the end of the ride and food (which is just a mental thing). On the other hand, if I'm eating about as much sugar I can digest, I can do the same power for five odd hours then run a marathon afterwards (and the whole ordeal preceded by a bit of a swim) and feel fine.

The last summer I went off to try to do a sub 10 double century on flatish ground, counting on doing 200W for the duration - there I was drinking carb-electrolyte mix and eating some sport fruit jellies which I find agreeable, trying to hit some 250-ish kcal per hour or so. It was going pretty well until I slashed the sidewall of the rear tire. If that didn't happen, I think I would've pulled it off - but not if I were short-changing myself on fuel. I did do 207W normalized for 10 plus hours before computer battery gave up the ghost and stopped recording in a race this fall, but I felt thoroughly beaten on some of the final climbs (otoh, when the finish line was near and all the serious climbs have been done, I could produce power again - it wasn't my muscles couldn't perform, I just mentally broke down in parts). I couldn't have possibly done that without fueling (and if anything, if I had been fueling more it might've carried me faster up some of the hills; also if I had dressed for the occasion rather than getting chilled to the bone).

Even on shorter efforts where fuel isn't a real problem, mentally, when it's really tough to keep pressing hard, the taste of sugar in the mouth helps. So I guess, if you're trying to get the maximum out of yourself, don't shortchange yourself on fuel. If not, you ordinarily can but... well, if you have T2 diabetes I don't know how fasted riding would work for you.

PeteHski

This is EXACTLY my experience too. I could have written this entire post for myself. Even the power numbers and timings are identical! Your final comment about the taste of sugar in your mouth has been shown in research to be a very real effect. Pro athletes often swill a bit of energy drink around their mouth before swallowing to get that affect. Apparently it signals to your brain that fuel is on the way even if it isn't!

The_woo

The only benefit is to know how **** it is to bonk, and what the signs are so you can avoid it.

You're putting out weak power and feeling ****, your training will be garbage vs putting out full power, appropriately fueled.