Daniel4

In the middle of a long ride yesertday, I stopped at my favorite gourmet coffee shop and had a vanilla bean latte and had a banana.

Then on my return trip, I had a quick thought. The sugar that I had just consumed is giving me an energy boost. Will sugar eaten before I go to the gym give me enough energy boost to blow past my failure to set a new personal best?

I google and learned what sugar temporarily does in your muscle fibres but couldn't find if it would give you so much of a boost that you can work past failure. If it did that would mean more muscle fibre damage than normal and recovery would result in more muscle growth.

Iride01 

It will help you replace some of your glycogen stores fairly quick. So you get some immediate results when you consume sugar or carbohydrates while on the bike. Your glycogen stores get used a lot during the times you are nearing your max. You can't consume enough sugar/carbohydrates to totally replete your glycogen stores during the ride though. If you tried, you'll probably have a bloated stomach or be puking on the side of the road.

I've over simplified quite a bit. It's a somewhat complex thing that depends a lot on how you ride, the distance, the difficulty and a lot of personal preference.

I usually ride hard for over 90 minutes. I put carbohydrates in my bottles and take a swig every 10 minutes. Others prefer gels or other solid forms. Some like to stop and eat. Your choice. You don't have to do any if you aren't wanting to ride as hard as you can or keep up with others.

Your body fat, no matter how lean you are, will always produce enough energy to ride at a steady pace. You just may not have the quick energy you need to keep up with others that go hard up the hills or ride a very fast pace for quite a while.

Carbonfiberboy 

I doubt it. That boost during your ride might also have something to do with caffeine. I drink a beverage with a little sugar and whey protein in it before and after the gym. I don't think it does much if anything for that one workout, but I think it helps over time. I don't think it's a good idea to go to the gym hungry unless you're trying to cut. It certainly does help to consume carbs on the bike on any ride of over maybe 30 miles. That said, at any coffee stop I drink mine black. It's cheaper.

RH Clark

Personally, I feel most cyclists use way too much sugar. I feel there are more long-term detrimental effects than anyone realizes.

MoAlpha

It depends on your metabolic state at the time. After a few hours of moderate to hard going, available glycogen (stored carbohydrate) is depleted and the answer is an emphatic yes. After 30 min of tootling along at a conversational pace, no.

Incidentally, in the glycogen depleted state, most ingested sugar will be used for immediate energy needs and only about a maximum of a third (IIRC), if any, will be stored as glycogen. Moreover, in that state, glucose uptake into muscle is insulin-independent and immediate, hence it has very different health implications from sitting on the couch and eating Cap'n Crunch, i.e., very unlikely to have detrimental effects.

Bearhawker

How fast does any fuel you ingest get metabolized and made ready to burn?

I can't see there being any sudden/immediate fueling effect unless the body holds back some energy as a "reserve" and only releases it immediately if the system believes that more fuel is coming in. IE: you eat something the system recognizes as a replenishment and release the "reserves" it was holding back to keep you alive.

79pmooney

You can use white sugar (sucrose) as a drug to boost performance. It's not a big boost and mostly in your head but it is real - if you are using it with a body that has been completely sucrose free. (I say sucrose. I did this experiment long before the modern synthetic sugars in today's pop, etc.)

I went totally sucrose free in my racing days save a candy for the late mile of the my longest races and two cubes of white sugar in coffee on marathon rides to pull off the last 50 miles home. As a drug. And it only worked if I rarely used it.

Iride01 

I can tell the difference in whether I'm drinking water or drinking a mix with carbohydrates. If you are riding at a hard HR zone 4 and 5 pace for a while, then when you take that gulp or two of mix, you'll feel the energy coming back within 60 to 90 seconds. And back when I was using fructose/sucrose carbs, the surge in energy didn't last as long. With the maltodextrin that I use now, it seems to be a more steady release of energy that I feel longer between gulps from the bottle. Somewhat seems reasonable as fructose and sucrose are simple sugars where as maltodextrin is considered a complex carb.

If you are only a HR zone 2 and 3 rider, then you may not ever get enough energy deficit to notice.

MoAlpha

There is a reproducible positive effect of simply tasting a sweet solution (and spitting it out) on performance, so immediate effects are likely mediated by the nervous system effectively taking the brakes off in anticipation of the actual metabolic effect.

I think 60-90 seconds is an underestimate for real fueling, since we're talking about gut transport, passage from the capillary circulation of the gut back through the venous system, right heart, lungs and left heart, muscle uptake, and glycolysis, but it's measured in minutes.

Iride01 

I'm okay even it it is just some kind of placebo effect initially. I do know that my stats are not as good if I only use water for times I ride hard. So I'm pretty sure the carbs are replenishing some of the energy I'm expending when at or near anaerobic levels of exertion. And I'm able to push harder and longer on the climbs that I challenge myself on.

Bearhawker

Fructose is processed mostly (70%) by the liver (the rest seems to be intestinal from what I've read). Sucrose (table sugar) is half glucose and half fructose.

It would seem quite likely that you'd get whatever benefit you get much faster from sugar sources like maltodextrin that do not require the liver to do it's thing.

MoAlpha

It's sort of a philosophical question, but it's not considered placebo. This is presumably a specific physiological trait selected for in evolution because it allowed someone to go a little deeper into metabolic debt when fuel was shortly to follow. There is also an insulin response in humans and animals to the same thing, presumably to prepare the body to absorb carbs in the resting state.

MoAlpha

Fructose and glucose are absorbed across the gut by different transporters and there's pretty good evidence that incorporating a mix of glucose and sucrose in sports energy products delivers glucose to muscle more efficiently than using glucose alone, despite what you correctly point out.

Bearhawker

US Gov info on fructose and the liver

MinnMan

I think most of the responses here are missing the key point from the OP, which begins, "In the midst of a long ride..."

Yes, during a long ride replacing carbohydrates in whatever form will replace the glycogen you have depleted and give you a boost relative to the tired state you would otherwise have at the latter portion of a long ride.

Arguments about which carb/sugar gives you the most immediate boost are interesting, but all of them will give you some energy.

on the other hand, starting out with some sugar before your gym workout may not make that much difference, as your muscles are not beginning in an undepleted glycogen state

MoAlpha

Good review, but not US govt info and not relevant to fueling during prolonged exercise. The US govt merely provides access to the world biomedical literature via Pubmed as a service. NAFLD and the other bad effects of fructose are consequences of energy overload, not appropriate fueling in athletes.

RH Clark

What I would like to know is when glycogen stores become depleted, how much they are depleted, how fast they regenerate on sugar compared to being simply left alone.

I'm sure consuming sugar will immediately raise your blood sugar. I also know that your body will release insulin to lower it at some point. I don't know how much actual energy that may make available VS how you may just feel better for a short time by the blood sugar increase.

I am actually more concerned about the detrimental effects of the insulin it takes to lower blood sugar.

What would be the difference in someone who has entered ketosis compared to a high carb burner in replenishing glycogen from body fat compared to X amount of sugar in the carb burner? It does make a difference and they are questions worth exploring.

MoAlpha

Partial answer:

There are three (IIRC) glycogen compartments in muscle. Only one of them is readily available to energy metabolism and gets depleted under normal circumstances. The other glycogen may serve more of a structural role and only gets consumed under extreme conditions and it’s probably not a good thing when that happens.

Fat cannot replenish glycogen. Fat is either burned directly for energy in muscle or forms ketone bodies, which are burned in muscle and other tissues. Glucose can be reconstituted from amino acids and other scavenged molecules, but not in large amounts and under conditions where that mechanism is important, much of it is consumed by brain, which needs about 30% of its energy in that form, unlike other tissues. I don’t think know for sure, but I don’t think gluconeogenesis can replete glycogen during exercise.

Glucose uptake into muscle under exercise conditions is not insulin dependent and ingested glucose is cleared very rapidly without much insulin release.

Bearhawker

Fat absolutely is one of the "fuels" that are used by the liver (primarily) and kidneys (lesser extent and increasingly when fasting I think) for gluconeogenesis. Any non-carb source can be used: it's how non-carb-eaters keep their blood sugars up.

Acetone from keytone bodies can also be used as a substrate for the creation of glucose.

I do all my riding fasted and never run out of glucose. Haven't "bonked" once since I stopped eating carbs.

I am curious though about the impact of ingesting carbs ahead of high-output ride sections like hills or sprints - but I'm most specifically interested in the timing: I would want to know exactly *when* to take them, although I suspect that even with experimentation I would never really know.

Iride01 

I knew that you weren't describing a placebo effect, I was just saying even if it turned out it was only a placebo effect.

I don't ride hard in the colder part of fall or winter. Nor do I ride far or very often. So I switch to water for my rides. Initially, my body seems to want more water and the bottles get emptied faster than they should. I've wondered if it's my body expecting the carbs and asking for more when it doesn't find any in the first gulps. Eventually after several rides, it learns there isn't any carbohydrate to be had and the bottles last much longer.

MinnMan

'

At what distance? 20-40 miles, I believe you. 80-100, I don't.

MoAlpha

Keto riders are pre-bonked.

Bearhawker

Haven't ridden more than 100km yet this year. Over the last few years I've done several multi-day 100+ km days. One of them involved 4000m of climbing over the 3 days and I literally ate 1000 calorie suppers those days. Computer said I burned north of 5k calories each day, eating only 1000 calories at the end of the day. I planned on eating more but could not get more in.

Last year I did our local Fondo event: 94km day 1, 100km day 2, 60km day 3. Day 2 included a 400m timed sprint at ~ km 60 and a 1km hill climb ~ km 75. I did the thing on a fatbike (28T chainring) and didn't come in last in any category for my age group. Not even the 400m sprint where I averaged 30km/h. I was going to do the 150 Gran Fondo but the wind was 45+ km/h for the 1st half of that route and I determined I could not make the time cutoff with that kind of headwind so I dropped down to the 100km ride.

Trying to work through my arthritis in my right knee (lost 2cm off that leg in the 80s) and my spine and various soft tissue problems from a couple of collisions (2019 and a few weeks ago) to get longer distances in. I was expecting to be up to 160km rides by this time but I keep dealing with set backs... it would be nice to not get hit by a another car for a long while...

The week after my latest collision, I did this ride: Dusty Red Gravel Grinder. It was a hard ride considering I fell down the front steps taking the bike to the car and smashed my spine into the steps. My feet came right out front under me on the wet landing - bike in my hands nothing to break my fall.

So with any luck I will be into and past those distances in the spring. All fasted, like all my riding and other exercises, as I only eat in the evening. Nothing all day but water and electrolytes.

Iride01 

I have no doubt at all that one can ride without consuming additional carbohydrates during their rides whether long or short. I've done it. Body fat supplies energy at a fairly steady rate. I just have to manage my use of energy better and accept that I won't be as fast as I could be, or that I can attack a climb at hard effort.

MoAlpha

You can ride "forever" without fueling. It's just slow and you burn muscle.