TromboneAl

I hope this thread won't generate heated conflict. It's simply a report on my experiment yesterday with riding an unsupported metric century, and eating no carbohydrates before or during the ride.

The basic theory here is that people who are "fat-adapted" can burn fat more efficiently, and don't need to rely on carbs during exercise.

Some references:

What Does it Mean to Be Fat-Adapted? | Mark's Daily Apple

https://www.nsca.com/uploadedFiles/NS...%20Phinney.pdf

Since I've eaten low-carb for four years, I should be pretty "fat-adapted." Just for fun, I thought I'd do a ride with zero carbs. I didn't expect much of a difference between this ride and my normal rides, because I usually don't each much carb food during a ride.

Here's what I ate on a normal ride last week:

Breakfast (6 AM): 1 egg, one bacon, 1/2 avocado.
Pre-ride (10 AM ): 1 egg and 1 slice of cheese, coffee with 2 TBS heavy whipping cream.
During the Ride: 120 grams of almonds, macadamias, and pecans, liberally coated with electrolytes (NaCl, KCl, Calcium Citrate, Magnesium Citrate). One Quest bar, one cup coffee with 2 TBS half-and-half.

Total digestible carbohydrate: approximately 15 grams

Here's what I ate on yesterday's ride:

Dinner, night before: Hamburger patty with sugar-free ketchup and sugar-free mayo, 1 glass of wine
Breakfast (6 AM): 1 egg, 1 sausage
Pre-ride (10 AM ): 1 egg, black coffee with 2 TBS MCT oil.
During the Ride: 1 Aidell's Bacon, Mushroom, Swiss Cheese sausage (96 grams), 1/4 hamburger patty, 1 black coffee.

Total digestible carbohydrate: approximately 0 grams.

Note that I didn't eat the sausage necessarily for fuel, but mainly because I didn't want to feel hungry.

RESULTS:

I felt a bit more tired that usual towards the end of the ride. My energy on these standard rides varies quite a bit from one ride to the next, but on this ride, my energy was on the low end of the range.

However, my perception of tiredness was strongly influenced by feeling like I was going to barf. That's right, the sausage tasted great, but it was a big mistake. Combined with the black coffee, this really made me nauseous.

My average moving speed was 12.3 MPH for the normal ride, and 12.1 MPH for the zero-carb ride.

Here are the charts for the zero-carb ride:



And here is a comparison with a recent ride:



The laps in the red rectangle are the hill climb.

GeorgeBMac

Then why did you not publish it in the Low-Carb thread which has been set aside for just that purpose?

elcruxio

No one has ever contested the idea that one could exercise without carbs I think...

However (and I'm being nasty purely because I very much dislike the idea of low/no carb diet as lifestyle) 12mph for me at least isn't exercise... 15mph average is recovery speed...

hamster

I did this a few times, though skipping the sausage.

To the commenter saying that 12 mph isn't exercise - that really depends on terrain. There is a difference between 12 mph nonstop on the flat, and 12 mph averaging 67 feet/mile of climbing (especially if you throw in a bunch of traffic lights). My longest zero-carb ride in the last few months was 58 mi. with 73 feet/mile of climbing and average moving speed 13.9, and I assure you that it was very much an exercise (2010 kJ of work).

wolfchild

I have experimented with very low carb diet before for a few months and I also stopped taking supplements while on a low carb diet...The loss of weight, the loss of performance from low carb diet was just too much for me, so I went back to the way I used to eat before and I also started using few supplements which I've used before. I feel a lot better, my energy level are higher and I look a lot better now after going back to eating higher carb. My sprinting ability, speed, explosive power has really suffered a lot when on low carb...never again.

hamster

To me it's a question of balance. Going all-out low carb, during, before, between and after rides, does have all the effects you describe. On the other hand, you don't have to live on high-carb diet _and_ eat carbs during all rides. Both are extremes and the ideal strategy is somewhere in the middle.

wolfchild

The way I found balance is to eat the bulk of my carbs later in the afternoon and evening after my riding, working out and work is all done...I don't eat breakfast because when I wake up in the morning my tank is full and there is no need to spike my insulin with any carbs. I prefer to start my ride in a fasted state, and then consume moderate amounts of carbs and protein throughout the day... During the day I eat just enough carbs and protein to keep my energy levels up and prevent catabolism of muscle tissues...I pig out in the evening, before bedtime.

JimF22003

I'm pretty sure I could do a zero-calorie-of-any-kind metric. I've done 40 or 50 miles with no food many times.

Not sure what it would prove though.

Machka 

Yep. I made that mistake before a Time Trial. I only had a few minutes between getting home from work and heading out to the TT, so I quickly made myself a liverwurst sandwich. I love liverwurst at the best of times. But part of what spurred me on to greater speed over the 11 km of the TT was that I had to get off the bicycle and set the liverwurst free. At the end of the race, I dropped my bicycle and spent the next 15 minutes or so crouched in the ditch doing just that.

A half bagel with jam, or a couple bananas, would have probably been a better choice.


And yeah, of course we can do a metric century at 19.4 km/h on low carb. If you're fit enough, you could probably do that without much in the way of food at all. Not a big deal.

Rowan

I've done a full imperial century on just water. It proved I could do it, and it gave me an idea of what I could expect to do if I ran out of food on a randonnee, for example. But apart from that, it's not something I would repeat unless I had to.

The takeout from Al's experience probably is the need to match the ability to digest what's been eaten, especially when it's something that takes much longer to process than say, carbs, with the output at the pedals.

While 12mph might be training speed for some, effort to achieve that might be significant depending on terrain. There seem to be a few climbs and undulating terrain in the ride, which translates to some intensity... which means the protein is going to sit in the stomach stewing rather than being converted to energy.

FWIW, I think protein is an important part of food intake on rides, but in much smaller proportions compared with carbs. But if someone is on a low-carb diet, I think they just have to accept what others have said -- their intensity is going to be lower than others when it comes to longer distance rides.

elcruxio

If I calculated this correctly that would translate to about 1200m of actual climbing during the ride. That's pretty much the same climbing I have on my 100km loop (15mph boring slow ride and watching the hills not to overstress it)

Of course I need to eat constantly but you, know, carbs are rocket fuel.

hamster

What I find really funny, is that not three days ago in this very forum (long distance section) I had several people trying to convince me that 10 mph moving average is perfectly normal for a beginning cyclist on a hilly ride. And here it turns out that, on a hilly ride, 12 mph is not even an exercise and 15 mph is a boring slow ride at recovery speed.

The more you read, the less you know ...

elcruxio

It all depends of course. I don't consider myself to be particularly fast or in good shape. I also have the whole type 1 diabetes slowing me down something horrid.

10mph would be a good starting speed for someone starting from zero, as in not exercised in years.

15mph is a normal many hour average speed for someone in average shape.

I personally am striving for 23mph (40km/h?) Five hour speed on a tri bike. That would probably translate to maybe 20mph on a road bike. Of course that's likely never going to happen but one has to have dreams.

But this is also about fuel. What did you expect? That you could match the performance of of someone eating carbs by not eating carbs. That is not going to happen. Fat is slower than carbs and that leads to the situation where your hard work (due to lower efficiency fuel) is quite slow for me (due to the magnificient rocket fuel called carbs). And there probably are fitness differences as well.

TromboneAl

If I had bonked at the first big hill, and had needed to call my wife to pick me up, that would have supported the theory that I need more carbs, that I wasn't a good fat-burner, and I wasn't bonk-proof.

If I had felt strong during the entire ride, as strong or stronger than my average trip, that would have supported the theory that I was able to liberate enough fat to fuel my ride.

The result was somewhere in between, but confounded by the nausea.

I find it useful to see how my body works under different conditions, and test out some of the many theories out there. I'll try a water-only version at some point, just to see how my body behaves.

It is for me. I'm 60 and I've always been slow (even in my high-carb days). My average heart rate for that ride was 77% of my experimentally determined max heart rate. I could average 16 MPH on a flat metric, but not much more than that.

Spld cyclist

To be fair to the OP, you might need to recalibrate what "average shape" means. I think people who are very fit (especially if they ride with/compete against people who are even fitter) may lose sight of what average is. You're in superior shape to put up those numbers. Objectively, I know I'm well above average in cardio fitness, based on a treadmill stress test I took earlier this year and comparing it to published population data. The best I've done lately on longer rides is 15.1 mph moving average. That was on a 38-mile ride over "rolling hill" type terrain with substantially less total ascent as what the OP posted above.

I'm not arguing against your point about fuel. OP may have done better with more carbs, but 12.1 mph average for 63 miles over hilly terrain isn't too shabby in my eyes. I'm not sure I could do any better.

hamster

I did a similar calculation in the LD forum and I can repeat it here. Imagine a route that consists of 1 mile uphill at 4%, 1 mile downhill at 4% and 1 mile flat. That's approximately 70 feet/mile of climbing. Using Bicycle Speed (Velocity) And Power Calculator ("racing bicycle - hands on the tops"), rider weight 160, bike weight 20, to get the average speed to 15 mph I need 170 watt.

170 watt is easy to do for a 160 lb someone in average shape for an hour, but definitely not for many hours. My own personal 5-hour best is somewhere around 60% FTP. If this applies to that 160 lb someone, he'd need FTP close to 4 W/kg, which is far from "average shape".

And I haven't even stopped to consider traffic lights and intersections, which tend to murder average speed (moving as well as overall) by forcing you to brake to a full stop every few minutes. Maybe you don't have traffic lights in Mordor?

23 mph for 5 hours on a tri bike is even more unrealistic - plug the numbers into the calculator yourself and you can convince yourself that 23 mph on a triathlon bike over that 70 ft/mile course corresponds to 300 watt. If you can do (or even if you hope to do) 300 watt for 5 hours, you should be a professional cyclist.

As to the subject of fuel, to continue your analogy, carbs may be a good fuel, but they are in the gas station, and you need them in the tank (inside your muscles when you start riding). Eating while riding supplies muscles with external fuel and frees them from responsibility to store more carbs internally and to burn more fat.

gregf83 

My ride today was a little over 100km in 3:23 (~30kph) and I ate two dates which I could have done without. I didn't feel nauseous and burned a little over 2400 Cals on the ride.

I can go 160km with no food if I keep the effort steady and don't burn too many 'matches'

It's not clear to me that eating a low-carb diet makes you any more 'fat-adapted' than someone on a more normal balanced diet.

Machka 

It comes down to fitness.

When you are unfit, your body doesn't process fuel as efficiently as it does when you are fit.

That's why we suggest 200-300 calories per hour to beginners who are embarking on their first metric century or century or whatever longer distance. They need it to get through without bonking.

But after you've done several metric centuries or centuries, and lots of other rides over a season, you may discover that you can do that metric century on next to nothing.

elcruxio

Wat?

As I've understood it you eat carbs during a ride to supply the muscles with fuel to last hours. Depending on the intensity the glycogen storages of the body will last from 2-5 hours. Of course if you want to be burning 50/50 so half fat half carbs you need to ride at a very low intensity. The normal number for triathletes during their bike ride for example is 60/40 where they burn 60%carbs and 40%fats. If they keep filling the tank constantly by eating (60grams of pure carbs per hour) they can sustain the effort for much longer since they won't be running out of carbs during the race, if the calculation holds.

Eating carbs during a ride does not affect the body burning fat. The intensity does. And If you go over intensity, aka. go to the point where you burn 80% or even 95% carbs and little fat the body has difficulty going back to burning fat. The body likes the more powerful fuel so one needs to be careful during long rides especially on hills.

Eating carbs is simply supplying the muscles with the necessary fuel so that the body does not run out. Because if you do run out and have no glycogen to burn you are first going to have a bad time, and second your power goes down the drain.

Dudelsack 

Anyway, back to the OP: if it works for you, it's cool. I personally find it unattractive.

I did a forty miler yesterday fueled by one Egg McMuffin pre ride and 3/4 bottle of A&W root beer during the ride. I felt OK.

Dudelsack 

While I was typing the last post it occurred to me that I was scarfing down a three egg omelet with cheese, ham, Les herbes de Provence, and Cholula sauce. Good morning America, was it ever good. So I am sympathetic to your bias.

wolfchild

The reason you can do that is because you're very fit. Your body can store a little more glycogen then the average casual rider. A very fit body is a lot more efficient at using glycogen and fat then somebody who is average and even if you do run out of glycogen your body will switch over to using fat to keep you going, that switch can only occur in a person who is trained a fit. Anybody who spends a lot of time in the saddle and trains a lot can do that...It's not just about being fat-adapted, it's being bike adapted or exercise adapted.
I start my every ride in a fasted state and only ingest something after about 1-2 hours of riding.

gregf83 

Of course, even in a 'fasted' state your body can have plenty of glycogen stored.

Interesting article on the use of 'fat adaptation' strategies for improving endurance performance: “Fat adaptation” for athletic performance: the nail in the coffin?

jodyrew

I've doing all sorts of activities and I'm on Paleo diet. Didn't notice much of a difference. (That is, coupled with regular exercise)

Carbonfiberboy 

Exactly. About 15 years ago there was a brief fad for eating fried eggs and going riding in the morning. However, those practitioners found no benefit and serious riders don't do that anymore. The eggs were just excess calories. The idea that eating fat causes fat burning during exercise is unproven and a bit odd. Might as well rub in on your body as put it in your stomach. What causes an increase in fat burning on the bike is riding. That's been proven for some time.