Carbs per hour for endurance rides different than tempo and above?

[TheRich]

Seems like an unnecessary risk to depend on fat burning to fuel anything past BMR.

The science points towards that's what's happening at a low pace. Small amount of carbs and a high proportion of fat. If you're just pootling along, seems unnecessary to be eating a lot of any type of food, carbs, fat or anything it seems.

This does seem closer to being on the right track again from what people are saying elsewhere:

Total Out: 9700 cal
Total In: 3960 cal

You really would be getting close to that huge 5740 cal deficit. Maybe knock a few hundred off as the BMR figure of 2k earlier also included other calories for daily activities, which you would get much of on a 12 to 14 hour all day ride.

So back to square one. Are you really losing half a kilo of body fat a day if you do a ride like that? If you're fully glycogen loaded you may dip into some of those stores, but shouldn't deplete them if in theory you're taking in 60g carbs per hour, which is likely more carbs than what's needed for an easy pace as it is..

I see what people say about the science and then compare that to practical application...and it doesn't agree. The place I found your 60g/hour was incorrect, btw. It wasn't ~250cal/hour, it was ~350 by their own admission (one drink and two snacks/hour), and ignores any solid food that the TdF riders in question ate throughout the day...and it's half the duration you're talking about.

Just look at this: https://www.velonews.com/2018/05/traini ... nza_464709

He maxes out at 236 cal/hour of fat burning, you're (along with others are) assuming a much higher rate, over 400/hour in your case assuming a 14 hour ride. That's a recipe for disaster.

If you're going to utilize "the science," you need to actually utilize the science and the first step of that is to get a metabolic test. With that information you can build a plan, otherwise a plan to succeed would involve playing it safe and eating a lot.

[joejack951]

I see what people say about the science and then compare that to practical application...and it doesn't agree. The place I found your 60g/hour was incorrect, btw. It wasn't ~250cal/hour, it was ~350 by their own admission (one drink and two snacks/hour), and ignores any solid food that the TdF riders in question ate throughout the day...and it's half the duration you're talking about.

Just look at this: https://www.velonews.com/2018/05/traini ... nza_464709

He maxes out at 236 cal/hour of fat burning, you're (along with others are) assuming a much higher rate, over 400/hour in your case assuming a 14 hour ride. That's a recipe for disaster.

If you're going to utilize "the science," you need to actually utilize the science and the first step of that is to get a metabolic test. With that information you can build a plan, otherwise a plan to succeed would involve playing it safe and eating a lot.

I'm not sure where you are seeing that anyone is assuming 'over 400 calories/hour coming from fat'. My summary of the study's findings that was one should be able to expect 1/3 to 1/2+ of calories burned per minute (or hour) to come from fat as long as heart rate is kept in the right zone (which, of course, will vary by individual). In the link you posted, Chris Case maxes at 236 of 662 calories burned per hour coming from fat. That's about 36%. Seems to agree with the study's findings to me.

[edit] Re-reading some of Shrike's comments I realize that with some of the numbers he's using, he is suggesting burning 400+ calories/hour from fat. That does seem aggressive.[edit]

'Disaster' also sounds a bit hyperbolic when discussing essentially a training ride. Worst case, he needs to stop and get some extra food. Nothing lost but some time and money. I'm assuming he's smart enough to feel a bonk coming on and not to try and ride through it.

[Shrike]

@Rich

No, look at what he's doing and what I'm doing. Totally different! He's riding at race pace at DK. Fat utilisation drops off the harder you go.

I'm riding around recovery and low end endurance pace, say 160 watts. That's roughly 550KJ an hour. If I'm taking 60g of carbs an hour, that's only 300 cals an hour needed from fat stores. At such a low wattage/heart rate, 60g an hour is probably overkill, as I found already with that 8 to 9 hour test. I had too much left in the tank and could ride for extended periods at tempo and then even at threshold over 310 watts, and that's after 7.5hours of riding on just 50g carbs an hour.

I've been dieting slightly recently so no way was I fully glycogen loaded either. Breakfast was 600 cals. I had too much energy to spare and that's not even accounting for BMR.

You can't compare what I'm doing to TDf riders. Those guys are fighting against REDS. That's not a concern for me. For them it will be catastrophic. Even with the best strategy, some stage racers got hit by REDS - see the Michelton Scott study earlier this year.

[Shrike]

'Disaster' also sounds a bit hyperbolic when discussing essentially a training ride. Worst case, he needs to stop and get some extra food. Nothing lost but some time and money. I'm assuming he's smart enough to feel a bonk coming on and not to try and ride through it.

You can feel it in your stomach, slight hunger pang.. well before any bonk happens. You only really bonk if you're going at a decent pace and run out of fuel. At a slow rate, the game is quite different.

And like you say. Just eat more and have a break for a bit. No biggie!

I was hoping to test this on an extended effort this week, around 200 miles, but I've seen an opportunity to do the Fred Whitton challenge. We have one dry day in the UK this week so, I'll be fueling properly and having a shot at that.

Not letting this drop though, really want to know how this works in practice

There was some Norwegian guy who rode a massive distance on body fat alone I think.. need to look that up.

[joejack951]

I think what TheRich is doing is looking at your calculated deficit (~5700 calories) and dividing that by 14 to get 407 fat calories/hour. I disagree with some of assumptions that got you to that deficit, but otherwise agree that your fueling plan should work based on your experience and the numbers from the study. If we split the difference on our estimates, you get 290 fat calories/hour which seems totally reasonable. That's science there!

[TheRich]

@Rich

No, look at what he's doing and what I'm doing. Totally different! He's riding at race pace at DK. Fat utilisation drops off the harder you go.

I'm riding around recovery and low end endurance pace, say 160 watts. That's roughly 550KJ an hour. If I'm taking 60g of carbs an hour, that's only 300 cals an hour needed from fat stores. At such a low wattage/heart rate, 60g an hour is probably overkill, as I found already with that 8 to 9 hour test. I had too much left in the tank and could ride for extended periods at tempo and then even at threshold over 310 watts, and that's after 7.5hours of riding on just 50g carbs an hour.

I've been dieting slightly recently so no way was I fully glycogen loaded either. Breakfast was 600 cals. I had too much energy to spare and that's not even accounting for BMR.

You can't compare what I'm doing to TDf riders. Those guys are fighting against REDS. That's not a concern for me. For them it will be catastrophic. Even with the best strategy, some stage racers got hit by REDS - see the Michelton Scott study earlier this year.

Just look at his metabolic test, which is below your even 300 cal/hour estimate..

[bikeboy1tr]

I did a ride this past Sunday, 138km, 1000 meters climb, 31 avg, and 80% intensity for 4.5hrs. I weighed 78.6 that morning. Before the ride I had a Clif bar and during the ride 2 Dutchies, Clif bar, 4 Clif Bloks, 2 water bottles with sport drink and 2 waterbottle with Electrolyte tab in each. We stopped for coffee and a Pannini with a slice of Bananna bread. According to my Edge 530 I burned 2770 C and consumed 1200 C and Fluid loss was 3194ml and consumed 3187ml. I spent 35% time in Endurance and 34% Tempo HR and the temp was 28C with little humidity. We were 20 minutes to go and suddenly my legs started to get empty so I scarfed down 2 of the Clif Bloks and my last Clif Bar of which I included above. I got lucky and avoided the Bonk with some feeling coming back into my legs and head. Normally I can do this ride np with food every hour and a coffee stop but I thought we might make it back before I got to the point of bonking. That was a close one.
I also hate trying to get a clif bar down when going at a good pace so I use the Dutchies and hold out with the clif bar until near the end but also use the clif blok during the ride as its easier to get down. Point is for some reason I was extremely hungry that whole day and I had a good dinner the night before so sometimes you can get away with less and the odd day you cant.

[joejack951]

Just look at his metabolic test, which is below your even 300 cal/hour estimate..

Why are you so reliant on the data from this sample of one? People are (somewhat) different. Just because Chris can’t burn more than 300 calories from fat in zone 2 doesn’t mean someone else can’t. The study I found showed a fairly wide range of calories coming from fat from the different athletes. I’d trust Shrike’s experience from prior rides more than applying another athlete’s data to his situation.

Based on the numbers presented in that article, it appears that Chris would struggle to ride at any intensity for two hours in a fasted state without consuming additional calories during the ride. Right there that makes us very different because I most definitely do not need to eat for a fairly hard two hour ride first thing in the morning.

[TheRich]

Just look at his metabolic test, which is below your even 300 cal/hour estimate..

Why are you so reliant on the data from this sample of one? People are (somewhat) different. Just because Chris can’t burn more than 300 calories from fat in zone 2 doesn’t mean someone else can’t. The study I found showed a fairly wide range of calories coming from fat from the different athletes. I’d trust Shrike’s experience from prior rides more than applying another athlete’s data to his situation.

Based on the numbers presented in that article, it appears that Chris would struggle to ride at any intensity for two hours in a fasted state without consuming additional calories during the ride. Right there that makes us very different because I most definitely do not need to eat for a fairly hard two hour ride first thing in the morning.

Because it is actual data, not guess work/motivated reasoning.

I also said to take a metabolic test if one wants to start disregarding accepted practices...for no reason other than to just do it.

By all means, have at it and report back, preferably with power data.