From Newsgroup: rec.bicycles.tech
On 7/8/2026 2:34 PM, AMuzi wrote:
On 7/8/2026 1:15 PM, Roger Merriman wrote:
AMuzi <am@yellowjersey.org> wrote:
On 7/8/2026 11:35 AM, cyclintom wrote:
On Tue Jul 7 20:53:38 2026 Roger Merriman-a wrote:
cyclintom <cyclintom@yahoo.com> wrote:
Today iz my wife's 78th birthday. She went out to lunch with the ? >>>>>> Church
Ladies and I'm trying to decide if she is going to bring something >>>>>> home
or if I should try to eat something for the 1700 calories I burned >>>>>> up on
today's ride. I don't know what is going on because I have
breakfast and
lunch and maybe a glass of wine in the evenings and my weight hasn't >>>>>> moved from 215 in three years. Thats with 4,500 to 5,000 miles of >>>>>> yearly
riding. My pot gut hasn't changed at all.
Your not burning 1700 calories on a 27 mile ride at 11mph, I do a
little
less distance on the commute at same speed at least on the old MTB. >>>>> Works
out at realistically maybe an extra cup of coffee per day as
cycling is
general efficient. Certainly not 1700 calories!
Likewise you?re not pushing out 150watts I have no idea what you?ve >>>>> done,
but the guys on the chain gang loop pushing out 150watts are
averaging 17
mph not 11mph, unless it?s a gravel loop with myself and uk Gravel has >>>>> tendency to be more old byways so less unpaved roads more MTB lite,
particularly in winter where you can expend a lot of effort for very >>>>> forward movement!
In short need to eat less or probably better to just ignore it and
enjoy
life! I do want to loose a bit, as it?s gained last few months due to >>>>> erratic eating. About a stone more or less, which is absolutely
doable.
Ideally be 92/4KG so 203/207 but I?m 216 it would also in Stones
which I
like most uk folks use put me under 15 stone than over it!
Don't tell me, tell Garmin they are all fucked up. I'm not making these >>>> numbers up. My coffee has near zero calories and your's accounts for 27 >>>> miles at an average speed of 11 mph and 370 feet of climbing?
*Tom*
My commute is around 11 something miles depending on the exact route, I
have number, itrCOs past Heathrow so pan flat with around 200ft of
elevation
ie sometimes more sometimes less again route dependant.
Bike and route dependant average speeds are 11/14mph on the commute.
Again
these donrCOt burn much calories!
I like some others here are used to the numbers yourCOll see from someone
using a power meter and yours despite what your Garmin and Strava
accounts
may say just arenrCOt believable, no idea what yourCOve done but
absolutely no
way your pushing 150 watts, at 11mph average on a flat route.
Look again at your setup.
As the pithy Seattle Sutton often noted, if your exercise
and calorie intake numbers are right, you're either dead
already or comatose.
Noting also that calories are essentially an approximation and should
always be taken with some caution! Ie calories are the energy calculated
within food, not the amount of energy that will get digested.
Roger Merriman
Well, that's true but for healthy humans it's close enough.
Total calories consumed and actual power output are the prime points of error. Or fiction, if you will.
Modern on-bike power meters are nearly as accurate as laboratory
measurement equipment. The power displayed is about as accurate as
you're going to get anywhere. Since there is a direct conversion between
watts and calories, the number of calories required to go a certain
speed over a certain distance with a certain load (rider weight and co-efficient of drag) is well defined. These are the numbers that Garmin calculates.
The issue is how efficiently the rider generates that power. There is a
lot to consider here, but even highly-trained humans are less than 25% efficient with regards to the amount of calories consumed versus power
output:
https://pmc.ncbi.nlm.nih.gov/articles/PMC3761728/
https://www.procyclingcoaching.com/post/is-cycling-good-for-weight-loss
Garmin does actually use this 25% factor when calculating the calories
burned, so when it suggests tommyboy burned about 1700 calories, yes, he burned about 1700 calories. This might not be 100% accurate, but
considering there isn't much variation in the 25% factor between a well-trained athlete and an 80-year-old dude (maybe as low as 20%), if
he ate 1700 calories he would be pretty close to replenishing what he used.
To be fair, the number tommyboy is quoting is about right:
https://www.calculator.net/calories-burned-calculator.html?activity=1&activity2=Cycling%3A+slow&chour=2&cmin=15&cweight=200&cweightunit=p&ctype=1&x=Calculate
So his 1700 calories would result in about 425 calories over ~ 2.25
hours at the pedals.
Here's the rub - replacing what you burned doesn't lead to weight-loss.
If tommy wants to drain his pot gut, he's going to have to eat a
significantly lower number of calories than what Garmin says he spent.
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