# How much carbs per mile/per hr do you use?



## lawrence

Does anyone know how many carbs per mile, per 10 mile ride, per hour, or what ever you burn when riding?

Is there a chart for this?


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## magnolialover

*Everyone...*



lawrence said:


> Does anyone know how many carbs per mile, per 10 mile ride, per hour, or what ever you burn when riding?
> 
> Is there a chart for this?


Everyone is different, there is no good answer, and aside from that, we burn calories in the form of something else.


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## GOC50GO

It ultimately depends upon oxygen uptake. And, your body weight directly influences how many calories you burn during physical activity. BTW, it's best to go by calories burned per minute as "per mile" can vary the amount of energy needed based 
on factors such as, terrain and wind resistance (i.e., kinetic forces). You can use what is referred to as METS (metabolic equivalents) to estimate calories burned per minute per kg of body weight depending upon effort/intensity. A MET is an expression of the rate of energy expenditure at rest. Thus, using this as our base, we can estimate how many METS are required to perform the activity. For example, bicycling at 14-15.9 mph has a value of 10.0 METS. There is a table (complimentary of many exercise physiology textbooks) that gives MET values based on effort for different physical activities. Once you get your MET value, you can plug into the following equation to get energy expenditure: Energy Expenditure (kcal per min) = 0.0175 kcal x METS x body wt (kg). As an example, a 150 lb (70 kg) person cycling at this rate would be expending 12.25 kcal per min. I guess then you could get a rough figure for "per mile" by dividing total time for your ride by how much distance you covered and get time per mile and then multiply that by kcal per min. Thus in our example, if this person rode 14 miles in one hour (60 min) that would be an average of about 4.28 min per mile mulitiplied by 12.25 kcal per min, resulting in approximately 52.43 kcal per mile. Did I make it clear as mud? Probably, more science than you wanted.  But, I hope this helps.


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## asgelle

GOC50GO said:


> Probably, more science than you wanted.


Or less. Riding at 16 mph burns 50% more calories than at 14, so your estimate begins with a 50% margin of error, We also know that energy consumed is not linear with weight except for steep climbing. Further, direct measurement shows that for me at 180 lb, 1 hour of riding at 14-16 mph burns something more like 350 Cal. So I think the first response was closer to the mark.

And since time and distance are directly related by velocity, and energy expenditure depends directly on velocity as well; why do you think time would be less dependent on velocity than distance?


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## lawrence

You are riding faster and burning more calories but you are also completing the ride in a shorter period of time. I read in many books if you walked a mile or ran a mile, you'd burn the same amount of calories, you would just complete the task in a shorter period of time. Though I don't buy this, I think running a mile you are burning more calories than walking a mile. Isn't bicycling the same, though you riding faster, you are completing the ride in a shorter period of time so the calories burned would be the same? You are burning the same amount of calories for your 20 mile ride? Now I do agree that a 200 lb rider is going to burn more calories than a 150 lb rider because he has more weight to carry and is working harder.


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## asgelle

lawrence said:


> Isn't bicycling the same, though you riding faster, you are completing the ride in a shorter period of time so the calories burned would be the same?


Cycling is not at all the same as running. Your not supporting your weight and the drag force from moving through air increases as velocity squared; this is the largest force to overcome riding on level ground. So no, the calories are not the same to cover a fixed distance at different speeds.


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## Kerry Irons

*Wrong numbers*



GOC50GO said:


> For example, bicycling at 14-15.9 mph . . . would be expending 12.25 kcal per min. Thus in our example, if this person rode 14 miles in one hour (60 min) that would be an average of about 4.28 min per mile mulitiplied by 12.25 kcal per min, resulting in approximately 52.43 kcal per mile.


These numbers are so far off as to be laughable. Any decent reference (Bicycling Science, Wilson, 3rd Ed, MIT Press) and TONS of reported power meter data will tell you that riding at 16 mph is around 22 calories per mile. These super high numbers get reported all the time, and they appear to be based on data collected from couch potatoes riding beach cruisers with under inflated tires.

For a 150 lb rider on a road bike, 18 mph is about 26 calories per mile, 20 mph is about 30 calories per mile, 22 mph is 35 claories per mile, and 24 mph is 41 calories per mile. For a 180 lb rider, you can add about 1 calorie per mile.


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## HomebrewMTB

Nevermind how much you burn, most people can only absorb about 250-300 Calories per hour. Hammer Nutrition has some good articles on their website. Obviously they will be product specific but you can look at the ingredients and work out equivalents. Hammer makes good stuff but it can get pricey if you ride a lot.

http://www.hammernutrition.com/za/HNT?PAGE=ARTICLE&CAT=VEGGIE&ARTICLE.ID=1252


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## tobylwillis

*Carbs NOT Calories*

Why don't you people read what the original post is? The question is how many carbs you burn. I've tried as well to find out and can't find an answer. I'm on a low carb diet and am on a budget of 40 grams/day. I'd like to be able to eat more because I rode more in a given day but need an amount of carbs burnt.


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## tlg

tobylwillis said:


> Why don't you people read what the original post is? The question is how many carbs you burn. I've tried as well to find out and can't find an answer. I'm on a low carb diet and am on a budget of 40 grams/day. I'd like to be able to eat more because I rode more in a given day but need an amount of carbs burnt.


Holy necroposting. You do realize this thread is 4 years old?
And the original post was answered quite thoroughly.


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## redcolnago

tlg said:


> Holy necroposting. You do realize this thread is 4 years old?
> And the original post was answered quite thoroughly.[/QUOTE
> 
> 
> what insight!


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## Drew Eckhardt

GOC50GO said:


> I guess then you could get a rough figure for "per mile" by dividing total time for your ride by how much distance you covered and get time per mile and then multiply that by kcal per min. Thus in our example, if this person rode 14 miles in one hour (60 min) that would be an average of about 4.28 min per mile mulitiplied by 12.25 kcal per min, resulting in approximately 52.43 kcal per mile.


The cycling numbers are completely wrong. Likely sources of their vast errors are cycling power requirements not increasing linearly with weight and flat values for ranges of speeds where power to overcome drag increases with the cube of velocity.

1 Watt = 1 joule/second, so 100W for 1 hour = 360,000 joules or 360kj. 1 kcal = 4.2kj although cycling metabolic efficiency peaks around 25% so you can approximate 4 kcal in = 4.2kj out and round to 1 kcal in = 1 kj out. I measure about 100W averaging 15 MPH out-and-back on "flat" terrain which is 360 kcal / hour and 24 / mile; 150W at 17 MPH and 32 / mile; and 200W at 20 MPH and 36 / mile.

I went on a nice 108 mile ride last Saturday going over two mountains totaling 6500 (Golden Cheetah) - 7200 vertical feet* (ridewithgps, Garmin Summary screen) depending on whose numbers you believe. Climbing and braking descending meant a 13.5 MPH moving average. My energy output was 3680kj for 34 kcal a mile.

* Strava said 9000 using correction which is wrong

Energy substrate utilization varies with intensity, fueling, diet, and training. Increased intensity, eating before and during rides, and higher carb diets shift the balance towards carbs. The shift from intensity is somewhat sticky, so a brief hard effort like up a hill means more glycogen consumption on following lower intensity efforts. Training at lower intensities shifts it towards fat even when riding at higher intensities. Longer rides shift it towards fat.

Doing things well you can get about 80% of your energy from fat at an endurance pace, dropping to under 25% at an intensity you can only sustain for 20 minutes. You might use 4.8 kcal / 1.2 grams of carbs per mile averaging 15 MPH on flat terrain and 17 kcal / 4.25g at 20 MPH where that's a 90% effort for you.

Note however carbs out don't need to come from carbs in - gluconeogenesis can fill up your liver and muscles with fat or protein as a source, just not fast enough to support you while riding.

Carb needs are lower than most people think. I didn't bonk on 125 Calories/hour including 22g (88 Calories) of carbs (1.6g and 6.5 kcal / mile) plus a chocolate chip cookie, whatever I netted from breakfast, what was in my liver (~100g and 400 kcal), and what was in my muscle fibers (400g / 1600 kcal total in your whole body, but you can't use what's in your upper body, and on endurance rides the glycogen in type IIx muscle fibers is inaccessible - so maybe it's 200g/800 kcal there). Normally I don't bother eating on rides under 4 hours although the math suggests I could go much longer.

You'd need to have your Respiratory Exchange Ratio measured while riding a bike or ergometer to know what your exact numbers are. Check the local universities - around here the Stanford Human Performance Lab can do it. You can also just experiment - ride farther without eating until you find you need an energy bar brought along as an emergency reserve.

Rob Gray posted his results on the Wattage list:


 *%FTP*​*Watts*​ *HR*​*Total kcal/hr*​ *Fat kcal / hr*​*Carb kcal / hr*​45%​131​99​607​473​133​50%​ 146​ 101​616​466​150​55%​ 161​ 105​673​548​125​65%​ 190​ 114​759​563​196​70%​ 204​ 119​ 823​539​284​75%​ 219​ 127​877​561​316​80%​ 234​ 129​906​554​351​85%​ 248​ 133​950​535​415​90%​ 263​ 136​963​483​480​100%​ 292​ 141​1,080​480​600​105%​ 307​ 147​1,152​328​824​


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## Drew Eckhardt

lawrence said:


> You are riding faster and burning more calories but you are also completing the ride in a shorter period of time. I read in many books if you walked a mile or ran a mile, you'd burn the same amount of calories, you would just complete the task in a shorter period of time.


Running you don't go fast enough for aerodynamics to have a significant impact.



> Isn't bicycling the same, though you riding faster, you are completing the ride in a shorter period of time so the calories burned would be the same?


No. Cycling is fast enough that aerodynamics matter a lot. Aerodynamic drag increases with the square of velocity, so going twice as fast over a given distance takes 4 times the energy.



> You are burning the same amount of calories for your 20 mile ride? Now I do agree that a 200 lb rider is going to burn more calories than a 150 lb rider because he has more weight to carry and is working harder.


Yes, but it doesn't matter much especially on flat ground.

50 pounds is 23kg.

There's rolling resistance -

23kg * 9.8 m/s^2 * 32000 meters * .004 Crr = 29kj or kcal around the best observed net metabolic efficiency cycling.

29 / 20 miles = 1.5kj / mile out of ~24 per mile at 15 MPH to 36 / mile at 20 MPH on "flat" terrain so you're looking at just 4-6% more energy for the heavier rider at typical recreational speeds assuming similar aerodynamics.

and potential energy climbing - 

On my last 108 mile weekend ride, I climbed 6500 vertical feet.

6500 feet = 1981 meters 
23 kg * 1981 meters * 9.8m/s^2 = 447 kj from climbing

108 miles = 156,700 meters
23 kg * 156,706 meters * 9.8 m/s^2 * .004 = 157 kj from rolling resistance

Together that's 604 kj / kcal more for an extra 50 pounds.

My total energy out was 3680kj; so an extra 50 pounds would have bumped that 16%.


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