Calorie accounting

[quixoticgeek]

My wahoo + hrm combo gives me a rough indication of calories burned during a ride. But I'm a bit confused how to account for them as part of the rest of the day.

Assuming I'm burning the recommended 2000kcal rda for a woman. And I do  ride that wahoo says is 2000kcal. Does that mean my total output for the day is roughly 4000kcal, give or take a smudge, or should I be accounting differently?

Am trying to not have too big a mismatch in input vs output each day, aiming for a ~500kcal deficit each day.

J

[hellymedic]

Assume you are burning around 80kcal per hour at rest and 400 or whatever per hour when riding.

The simpleton in me budgets on a 'per hour' basis.

Estimates of energy usage on exertion can be fairly wildly inaccurate.

[sojournermike]

Assume you are burning around 80kcal per hour at rest and 400 or whatever per hour when riding.

The simpleton in me budgets on a 'per hour' basis.

Estimates of energy usage on exertion can be fairly wildly inaccurate.

To witness Garmin estimates me at 1025kCal for tonight’s 8 mike run and Strava at 1300kCal using the same data. I think that Garmin is closer and it does get to a sensible set of numbers when I ride and use a power meter, but it’s still only a guide.

[Paul H]

I put it on a spreadsheet and played around with it based on 1kg weight loss requiring 7,000 calorie deficit, I ended up with:
2,300 with usual activity
plus
30 per km cycling
200 an hour walking
500 per 45 min gym session

It took a bit of adjustment to find the right formula for me, but that has become a pretty good weight predictor if I'm accurately counting the calories.  There's too many variations for it to ever be 100% and of course as you lose weight it ought to be readjusted, it's still good enough for me. I've also found weighing myself every day and averaging it over a week removes most of the fluctuations and looking at the calorie deficit weekly rather than daily makes life easier.

I only seem to be able to lose weight if I get obsessive about it, then I don't find it as hard as the thought of doing it.  If only it was so easy to keep it off, it seems every few years there's an excuse to put it all back on...

[hellymedic]

Assume you are burning around 80kcal per hour at rest and 400 or whatever per hour when riding.

The simpleton in me budgets on a 'per hour' basis.

Estimates of energy usage on exertion can be fairly wildly inaccurate.

To witness Garmin estimates me at 1025kCal for tonight’s 8 mike run and Strava at 1300kCal using the same data. I think that Garmin is closer and it does get to a sensible set of numbers when I ride and use a power meter, but it’s still only a guide.

Hate to say this but at 5-600kcal/hour and a speed of 7mph, I really doubt you will have used as much.

[hellymedic]

Been thinking about this over the last few hours.

You probably don't need to budget for more than 400kcal per hour while exerting yourself; it's hard to absorb quickly and you are planning for a deficit. Only elite athletes actually burn >600kcal/hour (and there are some GROSS overestimates of energy usage out there!).

If you are Audaxing, eat what you fancy on the road and feed well in the 48 hour run-up to the ride.

A deficit of 500kcal/day means 6 'hungry' hours at rest.

I lost no weight when I had an 11,000 mile/year habit.

I wasn't counting calories but certainly did not pile in the thousands of excess some sites suggested I might have needed.

[simonp]

IME 25kph average is around 500-600kcal/hour on an Audax bike.

This was based on power meter data so much more accurate than the estimates you find from myfitnesspal, etc.

[hellymedic]

IME 25kph average is around 500-600kcal/hour on an Audax bike.

This was based on power meter data so much more accurate than the estimates you find from myfitnesspal, etc.

Out of interest, what terrain and wind?

[Jasmine]

Assuming I'm burning the recommended 2000kcal rda for a woman. And I do  ride that wahoo says is 2000kcal. Does that mean my total output for the day is roughly 4000kcal, give or take a smudge, or should I be accounting differently?

You need to check if the prediction method is supposed to be on top of your base metabolism.  It usually isn't. When I used to do very strict counting, I had calculated by basal metabolic rate for the day, then divide by 24 hours to give an hourly rate.  Then, if you do a ride that burns 800 calories, but it takes 2 hours, you replace the base hourly rate for those 2 hours with the 800 calories (400 each hour).  Basal rate is actually quite low, because it the rate burned when you are lying down (sleeping).

[sizbut]

If Wahoo is anything like Garmin take those kCal figures with a pinch of salt at the moment.

When I do a ride with my Garmin it will tell me X. Then I do the same ride but also with a heart rate monitor and the figure will be a lot lower and I suspect more accurate.  If I had a power meter I suspect it would be lower again and even more accurate.

The figure from just a GPS uses a lot of assumptions (even if you tell Wahoo some age, sex, weight info) whereas HR and power meter start to replace that with actuals.

Of course even better if you can get VO2 measurement at the same time but I don't think Garmin/Wahoo do that yet.

[quixoticgeek]

If Wahoo is anything like Garmin take those kCal figures with a pinch of salt at the moment.

When I do a ride with my Garmin it will tell me X. Then I do the same ride but also with a heart rate monitor and the figure will be a lot lower and I suspect more accurate.  If I had a power meter I suspect it would be lower again and even more accurate.

The figure from just a GPS uses a lot of assumptions (even if you tell Wahoo some age, sex, weight info) whereas HR and power meter start to replace that with actuals.

Of course even better if you can get VO2 measurement at the same time but I don't think Garmin/Wahoo do that yet.

These numbers are from the wahoo with a heart rate monitor.

J

[sizbut]

Indeed, just spotted that  . I will wake up shortly. At which point I'll realise it's the end of the week and I should fall asleep instead.

[hellymedic]

Maybe believe wahoo for the time you are riding, budget 80kcal per hour for the time you're not cycling and for six hours of 'starvation' for your intended weight loss.
Suggest you weigh and measure yourself frequently so that you have prompt indicators of which way things are moving.

Water shifts will might throw your weight measurements around and gas might cause variation in your waist size.

Hip/bum circumference is a good indicator but can be difficult to do consistently.