On ride fuelling: 1-1.5g carb per minute

bahzob

Since seen a number of threads regarding advice for on ride fuelling thought worth quick post re what (I think though please correct me if wrong) the standard advice is.

Maximum carbs that body can usefully process is between 1-1.5g per minute. 1g is max for normal food, 1.5g is claimed for specialist products that mix types of sugar (glucose/fructose).

Link (admittedly from Powerbar, which I dont happen to use but does seem to give pretty good overview):
http://www.powerbar.com/articles/18/Latest_Research_on_Carbohydrate_Recommendations_During_Exercise.aspx#

Its helpful to have a handle on this as, using info from food labels etc, its quite easy to work out how many grams of carbs there are in food, so how much you should take on a ride. Taking more probably wont give a benefit and may actually be counter productive.

Its actually not that much. On a recent 5:30 ride I did I got through 2litres of 100g/l sports drink and a 360g maltloaf. Totalled around 440g of carbs so about 1.1g per minute ridden.

chrisw12

Check your maths! :?

bahzob

chrisw12 wrote:

Check your maths! :?

Cold fingers.... 1.3g per minute

chrisw12

Oh, I missed that one! :oops: I was more concerned with your other (bigger) one.

Actually, re reading is it's me that's the idiot, which is lucky really as it ment you checking your maths


I thought when you said this 'On a recent 5:30 ride I did I got through 2litres of 100g/l sports drink and a 360g maltloaf. Totalled around 440g of carbs so about 1.1g per minute ridden.'

you ment that you'd taken in 360g+2*100 of carbs but of course maltloaf is not pure carbs. So I'm an idiot! :oops:

chrisw12

sorry hit edit twice

BeaconRuth

I think 'standard advice' for on-bike fuelling is probably about as much use as standard advice for RDAs and everything else - ie not really very much use at all.

I'm not one to count anything very carefully, least of all calories or grams of food I'm eating, but this thread has goaded me into working out how many grams of carbs I consumed on a recent 85-mile, 5 hour ride. The answer is 87g. So that's just 0.29g per minute.

If these guys, like in the article you posted, are going to tell us how many grams of carbs to consume for optimum performance, why is there no mention anywhere of body mass? (I haven't read the article in detail - but didn't see any mention in a quick scan.) Surely it can't be true that a 90kg cyclist should be consuming 90g per hour and I, at 55kg, should also be consuming 90g per hour?

Sorry - maybe the research itself was sensible and this article is just a summary that makes it look like bunkum. But that's what it is - bunkum. If you're going to look at things scientifically, do it properly or not at all.

Ruth

maverick75

"Surely it can't be true that a 90kg cyclist should be consuming 90g per hour and I, at 55kg, should also be consuming 90g per hour?"

It is dependent on body mass and should be 1 - 1.5 gram/hr per kilo bodyweight so it would be:

90kg rider = 90g - 135g per hour
55kg rider = 55g - 82.5g per hour

BeaconRuth

That's not what the article says.

Ruth

bahzob

chrisw12 wrote:

you ment that you'd taken in 360g+2*100 of carbs but of course maltloaf is not pure carbs...:

Thats right, in fact (at the risk of another maths error) its around 66% carbs (but in terms of carbs per weight still one of the highest).

maverick75 wrote:

Surely it can't be true that a 90kg cyclist should be consuming 90g per hour and I, at 55kg, should also be consuming 90g per hour?"
It is dependent on body mass and should be 1 - 1.5 gram/hr per kilo bodyweight so it would be:

90kg rider = 90g - 135g per hour
55kg rider = 55g - 82.5g per hour

There may well be some variance with body weight but its not as simple as this. The limiting factor is the ability of your digestion to process food. This is not going to be directly proportional to weight. Indeed there may well be no correalation at all. Put another way if you put your feet up and gained 35kg your digestion wouldnt necessarily be able to move from processing 60g an hour to 90g an hour.

Also did not say "should" consume 90g per hour. That's the maximum the body can process. Whether need that much depends on you and the type of ride being done.

BeaconRuth wrote:

I'm not one to count anything very carefully, least of all calories or grams of food I'm eating, but this thread has goaded me into working out how many grams of carbs I consumed on a recent 85-mile, 5 hour ride. The answer is 87g. So that's just 0.29g per minute

Yes I've done rides that are same. As mentioned one reason for post was to note there is an upper limit to to how much food/drink you can usefully consume as opposed to how little. (As a beginner the mistakes I made were all about trying to take and eat too much. I now know that for rides less than 2 hours really dont need anything more than water).

Whether you need to hit that limit depends on the absolute length of the ride, intensity of riding, level of fitness and natural metabolism. Finding this out for yourself comes with experience. However to help short circuit the learning process (which sometimes comes the hard way with a bonk (eaten too little) or throwing up (too much)) a starting point would be:
- What food do I like eating on bikes: (say bananas)
- How many carbs are there in a banana: (around 30)
- What do I like to drink do I like: (say flat cola to avoid any specific sports drink)
- How many carbs are in a large bidon of cola (around 80)
- How long am riding? (say 5:30)
--> banana at start then each hour (180 carbs) + 2 bidons of cola (160 carbs) would be a reasonable eating plan (+ extra water as needed)

vorsprung

If you ride at a lower intensity you can generate a large amount of the energy required from body fat. Carbs are still required of course

It's only at aerobic threshold that carbohydrate is used in preference to fat

Let's not use this reply as an excuse for yet another discussion of loosing weight by doing "long steady distance"

mclarent

vorsprung wrote:

It's only at aerobic threshold that carbohydrate is used in preference to fat

Disagree with that, it's about % contribution, but as you pointed out it's OT so I ain't going there!

bahzob wrote:

Whether you need to hit that limit depends on the absolute length of the ride, intensity of riding, level of fitness and natural metabolism.

Kerching!

bahzob

vorsprung wrote:

If you ride at a lower intensity you can generate a large amount of the energy required from body fat. Carbs are still required of course

It's only at aerobic threshold that carbohydrate is used in preference to fat

Let's not use this reply as an excuse for yet another discussion of loosing weight by doing "long steady distance"

Just to correct. Its not the case that you only use carbs in preference to fat at threshold. By and large the human body tends to work in analogue mode rather than digital. What actually happens is that the balance of usage shifts from fat burning to carb burning as intensity increases. (A while back, I had a test done in a lab re this. percent energy coming from fat went 110bpm 70%, 120bpm 60%, 130bpm 38 %, 141bpm 26%, 152bpm 27%, 160bpm 26%, 166% (my then lactate threshold) 19%, 170bpm 1%. 171-177 (my then "MHR") 0%)

So above threshold its true practically all energy needs come from carbs.(or, instead at very high/short intensity, anaerobic sources). That said, paradoxically, if you ride at threshold you probably don't need to take in many on bike carbs since by definition this will be a ride of around an hour or so for which duration you have got enough fuel stored in your muscles in the form of glycogen.

Exact proportions of fat vs carb burn by intensity will vary by individual. One theory is is that one way training works is by allowing you to burn fat at higher intensities. Having a measure of how many carbs you use on a ride is useful in this respect as well. If theory is right you should be able to ride longer and/or more intensely on same amount of fuel.

(by analogy if geeky like me you could end up with a "miles per carb" measure. Like mpg it will tell you how efficient your engine is and will likely to change with speed you ride. Pursuing same analogy glycogen store is size of your fuel tank and gels/specialist sports drinks are a bit like Shell ultimate, should give better mpg but best to test as engines differ)

Appreciate all above is academic for many but for those who ride 3+ hours its pretty key into. Every year etape and other sportives have writeups from those who bonked, threw up or came to fisticuffs at foodstops. It should be possible to avoid these if you have a good feel for your miles per carb.

fuzzynavel

bahzob wrote:

vorsprung wrote:

If you ride at a lower intensity you can generate a large amount of the energy required from body fat. Carbs are still required of course

It's only at aerobic threshold that carbohydrate is used in preference to fat

Let's not use this reply as an excuse for yet another discussion of loosing weight by doing "long steady distance"

Just to correct. Its not the case that you only use carbs in preference to fat at threshold. By and large the human body tends to work in analogue mode rather than digital. What actually happens is that the balance of usage shifts from fat burning to carb burning as intensity increases. (A while back, I had a test done in a lab re this. percent energy coming from fat went 110bpm 70%, 120bpm 60%, 130bpm 38 %, 141bpm 26%, 152bpm 27%, 160bpm 26%, 166% (my then lactate threshold) 19%, 170bpm 1%. 171-177 (my then "MHR") 0%)

I am all for burning fat but just getting ready to go out on my bike and getting the adrenaline/excitement going sometimes gets me to nearly 100bpm..... I couldn't be bothered plodding along at 10mph to keep in my heart rate zone for fat burning.
I think my lactate threshold is slightly above yours though (for heart rate) as I did an hour in the middle of my clubrun last saturday at around 180bpm average after I got dropped by the group and was trying to catch up again. I did catch them but was so knackered that I couldn't stay with them for long!

a_n_t

bahzob wrote:

fair enough but where do you keep 6 bananas!

chrisw12

a_n_t wrote:

bahzob wrote:

fair enough but where do you keep 6 bananas!

Well stick two up each leg and another one down the shorts. Looks really impressive. :oops:

bahzob: great info. on this thread, keep up the good work (but watch the sums )

The questions I now have is, how do you 'train your body to use fat at the higher intensities'

I presume by doing 2 hour+ rides at just below LT??

is this why sweet spot rides are so effective?

I'm also now left with these 'classic questions'

1) Is 2x1hour rides better than 1x2hr ride
2) What happens to the carb/fat ratio usage if you're starving yourself/near bonking?

Alex_Simmons/RST

chrisw12 wrote:

The questions I now have is, how do you 'train your body to use fat at the higher intensities'

I presume by doing 2 hour+ rides at just below LT??

is this why sweet spot rides are so effective?

By training to increase your power at Lactate Threshold and your aerobic capacities.
This is done by training at intensities from solid endurance pace through to intervals that induce VO2 Max.

The ability to utilise FFA as a fuel source is improved through training to improve our aerobic capacities (LT, VO2 Max), which ironically requires us to include some work at higher intensities that rely substantially (if not exclusively) on CHO as a fuel source.

chrisw12 wrote:

1) Is 2x1hour rides better than 1x2hr ride
2) What happens to the carb/fat ratio usage if you're starving yourself/near bonking?

1. It depends on what you are trying to achieve. No single day's workout(s) can be rated above others without the context of the overall training.

2. If glycogen has been significantly depleted then you are forced to slow down and ride at a lower intensity utilising FFA as the primary fuel source. Your body will use the fuel available and if no CHO is available, then simply put, you can't ride hard. You may also experience other symptons of "bonking" - light headedness, loss of control, inability to ride at pace etc

bahzob

Second what Alex says. Just one additional comment. If your events are over 3 hours long (as some of mine are) the "solid endurance rides" ( say 4-5 hours) are very helpful.

The key part about them is the stress on "solid" so that the intensity is consistently high throughout, with minimal time in recovery. This is tough. (I didnt really appreciate this until I got some proper coaching advice, I just thought it was a matter of knocking up the miles, so thanks to Beacon Ruth for putting me right.). These rides have a number of benefits:
- Helping increase your aerobic capacity
- On board fuel will be used up so you will need to refuel in order for the intensity in hours 4/5 to be as as solid as hour 1. This it lets you check out how much food/drink you really need and what works best for you in real conditions.
- You'll get attuned to any warning signals your body sends out so you can increase/decrease food/drink before its too late.
- Over time, hopefully, the intensity of the rides will go up while the amount you need to eat/drink will remain constant. This is one measure of training progress.