I was wondering about calories yesterday while riding with an unfit mate.

If i did a ride now whilst pretty fit and hardly broke into a sweat at all i would burn X amount of calories. But if i stayed exactly the same weight but had lost all my fitness and did the same ride on the same bike but sweated loads and struggled on all the climbs would i still burn the same amount of calories?

You'd burn more as you'd be less efficient (carrying more fat, heart working harder etc.), I would imagine as a percentage it would be a fairly small increase though.

HRM monitors estimate calories burnt based on the heart rate – probably not very accurate but heart rate must be relevant. Not only will your heart rate be slower on a given climb climb when fitter it will also return to a lower rate more quickly so less calories burnt.

we had similar thoughts yesterday – me and obi twa did the same ride – i did it in 13.5 hrs and he did it in 16.5.

calorie calcs say he burnt more calories – but my pace was higher so youd expect i worked harder ….

makes me laugh at how much of a guess those things are – i might as well flip a coin 😉

It's impossible to compare energy burn rates of organisms. I still can't believe the multi billion pound diet industry still gets away with it.

And another thing.

Lets say you have trail rat and obi twa doing that ride. Obi twa has worked for longer and presumably had to work harder (possibly because he's less fit) so he actually is more deserving of credit than trail rat.

so he actually is more deserving of credit than trail rat

trail rat is basically a pair of leg muscles underneath a pair of lungs, so he deserves no credit at all. In fact he could probably have ridden that much on the power of one tic-tac. 😉

(and yes, the fitter you are, the less calories you burn for a set amount of work…but day to day changes in your metabolism/weight/muscle tiredness/etc will alter how many you burn, so it's all guesswork past a vague 'do more, burn more' statement)

how many calories did my good old fashioned vomit use up though? . first climb of the day my local 16% gradient 2 mile widowmaker. Chasing a flyweight grimpeur up it on my 24lb giant ocr with 2kg carradice bag on the back

You'd burn more as you'd be less efficient (carrying more fat, heart working harder etc.),

the energy required for the riding would be the same, but fat has a lower metabolic demand than muscle so it's more efficient [at being alive]. Also if you're fitter you'll probably go faster and have more air resistance to overcome

A riding pal has a Garmin Edge 705 that is calibrated with his weight, age etc. and at the end of the ride it displays "calories burnt" based on speed, altitude etc.

We refer to these as "Thingies". We know they're not really calories, but they are roughly proportional to calories used, on the basis that the longer and harder the ride, the higher the thingies.

I think giving them any more respect than this would be folly.

I was assuming they were going at the same pace due to hardly breaking into a sweat when fit and sweating loads when unfit.

The Garmin calorie calculations are notoriously inaccurate (over estimated).

Trail_rat – cheeky. You've just added 45mins onto my time.

Calorie calculators reckon something in the region of 15000kcal for that ride.