RH Clark

[QUOTE=PoorInRichfield;22667144]Interesting video, at least to me, from GCN comparing carbs to fats to protein as fuel during a ride...

[/QUOTET

The comparison is useless unless the fat burners have been on very low carb and high fat for about 90 days to adapt.

Carbonfiberboy 

See post 55. There's no way around that graph. The issue is that the oxidation of fat requires more oxygen than the oxidation of carbohydrate, and our limit of intensity is our VO2max, no matter what we eat or burn. Therefore if one has no carbohydrate to burn, only fat, intensity is going to drop way off. Among endurance athletes, this state is known as "the bonk", and it happens no matter how fat adapted one becomes. Keto adapted athletes are in a permanent state of bonk. They can't put out anything like the watts that an athlete using carbs can, and that's because of the high oxygen requirement of fat burning.

This is all very simple, really.

https://www.researchgate.net/publica..._fat_oxidation.

RH Clark

That's all well and fine for the 1% of elite cyclists. I honestly doubt that many here would notice an adapted difference on most rides and they might get faster on their next carb fueled ride going keto on a few and dropping some body fat. There is a vast difference however when you go from mostly carbs to mostly fats. You will have horrible low energy for 3-5 days and after adapted I have particularly noticed a greater feeling of clarity of mind and plenty of energy for a 20–30-mile ride without being exhausted the rest of the day.

I do think carbs are fine fuel unless you want to drop body fat. What I do hate to see however are cyclists trying to eek out every bit of performance fueling up on energy bars and all kind of power bars. The companies that make that processed junk don't care about health nearly as much as profit. I do honestly think those processed foods are destroying our health over the long term.

Iride01 

So what are you saying.... all of us that eat carb's are overweight and obese? And that the only way to easily lose weight is to stop eating carbs?

I think if you look at all the overweight people, just as many of them have failed on a keto diet as have failed on any other diet.

I'm glad to hear that you consider me to be in the 1% of elite cyclists. <grin>

Carbonfiberboy 

Really? A 20-30 mile ride? When I started endurance cycling, I was on my lips after a double century. After doing more high-mileage rides over the next few years and getting the nutrition more dialed in (more high glycemic carbs during), I felt fine after a double and a shower. A little tired, but not too bad, certainly not exhausted. Driving myself home after a 300k or 400k was fine, even though it was usually dark by then. That's all just from training and getting plenty of carbs. My experience is not unique or even unusual. It's normal for experienced endurance riders.

So getting plenty of carbs on the bike is not about the top 1%, it's for ordinary cyclists who ride for sport and enjoy a long climb. One gets that adapted simply by riding. The fat-burning part kicks in by itself. As it is said, "fat burns in a carbohydrate flame." Endurance athletes spend a lot of time riding below their VT1 - they have to. That increases their max fat burning ability. I've been doing group rides for decades. I've never met a keto rider on any of them. Why? They couldn't begin to keep up. It's definitely not the 1%. If anything, the 1% are the keto riders whom I never meet.

I'm 77 and weigh 5 lbs. over my high school graduation weight. That extra weight is mostly muscle. I'm not skinny though. BMI is 23. I can still do 150 mile day rides. I've been eating organic pesco-lacto-vegetarian for about 50 years, but on the bike it's all rocket fuel. That's what folks do because that's what works.

Try doing longer rides. IME a well-trained ordinary club rider should be able to ride a century on any given day, no special prep, just get on the bike and take plenty of fuel.

https://www.gssiweb.org/en/sports-sc...uring-exercise

• Quote:

  However, increasing fat oxidation during exercise is not associated with improvements in performance.

RH Clark

You're just too awesome for me dude, and you already know everything so there's no use discussing it. No hard feelings though. I'm still smiling, and I wish you the best.

Iride01 

Your idea of discussion seems to be that we all have to agree with you.

I think discussion is stating what you believe, stating what in another persons statements that isn't believed and sometimes adding supporting information for a viewpoint.

RH Clark

Maybe I was just having a bad day. Hope you have a good one.

PeteHski

I think you are looking at this too much from the perspective of someone who was previously obese. I really don't think energy bars (eaten for athletic performance) are a major health issue in the bigger picture. The real killer is a modern sedentary lifestyle, combined with a junk food diet. I don't think that should be confused with consuming carbs for athletic performance.

Carbonfiberboy 

I'm hardly awesome. Physically, I'm quite untalented. I had a hard time getting my mile time under 8' so I wouldn't have to repeat Basic Training. That was during the VN war. However, I am a talented student. I learned how to ride by always riding with people who were faster than I and asking them how they did it, then using that information to experiment on myself. I've done the same thing here on BF. I've asked a lot of questions, learned a lot and continued to improve over the years, that is w/r to my age group. So yes, I've learned a lot.

That's normative behavior in the cycling world. You are on to something - the hardest thing to learn is nutrition, again in my experience. Training is actually pretty easy. Almost anything works if you do enough of it. Food isn't like that! It's more like saddles - different for everyone in the details, but very similar in the macro. I know of a couple people on BF who fuel just like I do, but no one that I've ridden with, though they're all carb-fueled riders. Everyone has to experiment and find out what carb-heavy on-bike regimen works for their stomach, taste buds, and physiology, say between 100 and 250 Calories/hr. for rides over maybe 1.5 hrs. Below that, just water is best. What one eats off the bike is much simpler - just has to have enough protein, vegetables, and a little fat. Off-bike carbs can vary with the weekly volume. Low volume = little carbs. High volume = lots of carbs.

There is an issue with very low weekly carb quantity though. It turns out that the more one concentrates on burning fat, the worse one's carb burning ability gets. The reverse is also true. That's why all training plans feature some long, steady distance (fat) and some hard riding (carbs). Thus both energy systems get a workout and function well. Training is just as much about working your energy systems as it is working your muscles, and maybe more about the former. That's an issue I have with HIIT - not enough fat burning. If one is going to ride very far and hard, one wants to be a good fat burner.

RH Clark

I do agree with you in general, but I still think processed foods in any form are more harmful than most realize. Do a deep dive into every ingredient and you might agree.

I'm not arguing that athletes would perform better during ketosis. What I am arguing is that many cyclists may benefit from some ketosis and fasted cardio, particularly if weight loss is a goal.

What I object to is an attitude that whatever the pro's do is what every cyclist should do. Every cyclist is certainly not cycling at the same levels, at the same fitness, nor do they even have the same fitness goals.

PeteHski

Most people who take their training and health reasonably seriously are well aware of the harmful effects of processed foods. It's actually the couch potatoes who are largely ignorant in that regard.

Pro cyclists at the top level are mostly fuelled these days by home-made minimally processed carbs. But they usually enjoy the odd Snickers bar as a treat

I don't think anyone is saying that we should all copy exactly what the pros do, but the principles do largely apply to anyone looking to improve their performance - even modestly.
Personally I don't tend to overthink any of this. I think the fact that I train consistently with realistic performance goals and maintain a healthy weight and lifestyle has way more impact on my overall health than whether or not I munch through a few processed carbs along the way. I do however try to choose energy bars with as little processing as possible (there are a few niche brands who make an effort in this regard) or occasionally make my own if I have time. Off the bike I try to eat as many whole foods as possible, without obsessing over it.

OBoile

Are they? Certainly some processed foods are bad, but saying "in any form" is a little much. Is there even a reasonable definition of what makes a food "processed"?

Iride01 

Processed foods and Keto aren't in any way the same thing. So seems a changing argument now with a moving target!

ZHVelo

I went from an already low 67kg to 65kg at 183cm eating almost only carbs.

Your last paragraph shows that you don't really know what you are talking about, and have just bought the keto lie. You somehow equate carbs with processed and junk food. Well guess what, fat is the quintessential junk food.

PeteHski

Bingo! Carbs appear to have a bad rep in the popular diet world.

RH Clark

I suppose it depends on what your training and nutrition goals are. The diet of an athlete that just needs to get a little leaner doesn't need to be the same as someone needing to lose 50-100 lbs. Unfortunately, we are in a world in which morbid obesity is on the rise.

PeteHski

I do realise that. It's just that the latter group often appear to believe that carbs are the devil's food or only suitable for elite athletes! Unless I had a specific medical reason for not consuming carbs, I would choose a varied and balanced diet over keto any day.

RH Clark

I do agree in general. The issue is that really obese people have put themselves in a drastic situation. If they knew how to eat reasonably healthy, they wouldn't be in such a situation to begin with. In their case, I think a more drastic measure is called for.

GhostRider62

I forget what I have written on my experience with ketosis but wanted to correct a few erroneous comments by others. Bonking is when the brain lacks sufficient energy substates and you just doing into ******g la la land. Glucose, lactate, and "ketones" can all burn just fine upstairs. Some equate bonking with depletion of glycogen in the working muscles but that really is not bonking; nonetheless, a properly fat adapted keto endurance athlete cannot bonk. Period. I have ridden very long distances at reasonable efforts (around 55-60% of VO2 max) with no food and did not bonk. In fact, I would characterize myself as having been bonk-proof.

WRT to long endurance riding, the limits are not power. Rather, they are primarily energy source limits and fatigue. A high ability to burn fat is not the exclusive domain of keto athletes.

Having been a keto athlete, I would never have denied my ability to call on glycolysis when needed despite the fact most of my event depended on my ability to utilize lipolysis. Practically, it just meant I needed to eat fewer carbs to fuel the ride. The benefit to lots of miles or volume just around the LT1 threshold is developing lets call it the mitochondrial engine (without getting into enzymes, transporters, and signaling). Type 2 and type 1 muscles are always being used. When below LT1, almost all of the lactate is being used for fuel and is not being seen when you stick your finger or ear and measure lactate. That is the reason world class swimmers, runners, and professional cyclists do tons of volume. One could think of the type 1 fibers as gigantic vacuum cleaners for lactate or alternatively, the glycolysis provides the energy for the type 1 fibers. How does an endurance athlete get to a fractional utilization of 90-95%? Not on Trainerroad.

Fat people have such messed up metabolics that it (hardcore keto) really does not apply to most of us although I can appreciate the benefits. I could eat as little as 30g of carb on a rest day or as much as 300g on a ride and still be in ketosis.

I went out of ketosis on the Trans Am Bike Race (TABR) because it was impossible to do on 4300 mile self supported race. Was I slow as a keto athlete? My key brevets were all done in less than 60% of the allowed time and I was working on doing them in under 50% of the allowed time. I did PBP in 54 hours solo. I ain't never seen no club rider do that no matter what they did eat. So, Keto can work. I don't do it no more. It is a lot of work when you are married to an Italian wife who loves pasta and pizza. I plan to do my brevets in 2023 and PBP out of ketosis but I am older and better, so, I expect to get faster.

PeteHski

That may well be the case. But that doesn't mean carbs are bad news for the rest of us.

MoAlpha

Agree with all of the above and well stated.

Now explain this to me: I am a skinny little gink who, rides 10-15 hrs a week, eats a relatively low carb diet diet (what wife prefers) and hasn’t bonked on the bike in decades. However, if I put in a six hour day of easy sailing with the spouse, by the time we get to the dock or anchorage, I am nearly always starting to bonk (I know the feeling) and after I get the anchor down and the most important things semi-squared away, I simply collapse, to be revived only by copious carbs and the immediate promise of gin and tonic. An hour later, I’m fine. I have tried to time Clif Bars throughout the day and it helps a bit. Notably, I never crash metabolically on ocean races, where the watches are only 3 or 4 hrs and regular old sleepiness is the big problem.

I think I need the continuous muscle activity from cycling to stay up, but I don’t understand how that works. Not enough lactate for the brain?

RH Clark

I don't think carbs in general are bad news. I regularly consume organic fruits and vegetables. I do think low carb is a good strategy to lose weight, especially any significant amount of weight.
I also think too many supposedly health-conscious cyclists are consuming too many carbs from processed foods and excusing it as a reward for the hard effort, having little thought about what chemicals they are consuming,

RH Clark

Have you ever tested your blood sugar when you feel like you are bonking. Is it 6 hours without calories that gets you feeling bonked? Do you often go 6 hours without calories otherwise?

PeteHski

Round and round we go, lol.