Tracking calories from cycling/bike riding

MJW12020

Hi - I'm sure this has been asked but my search did not reveal an answer.

How does everyone most accurately record calories burned while bike riding?

For the first nine months or so of my weight loss journey I walked and did workouts, tracking everything through a Fitbit Charge 2. It must have been fairly accurate as my weight loss aligned with my calorie deficit. More recently I have taken up cycling and my Fitbit readings have tended to be below apps like Map My Ride. I have not been too concerned, but yesterday I did a 60km ride (and a couple of workouts as the cycle trail went right past my gym on both outward and return legs). I wore a heart rate monitor the whole time, but can't connect this to MFP. The HRM (which is set up with all my data) said I burned around 2300 calories; Fitbit had it at 1500.

I still align my calorie intake with expenditure, but I really don't want to lose any more weight and don't want to undereat. There is a risk of this if I consistently undercount my calorie burn.

What have members found is the most reliable way of tracking cycling calories in MFP (ideally while still using Fitbit for other activity)?

NorthCascades

Most accurately is with a power meter. It isn't even close. A power meter will tell you how many calories you put into the bike to within +/- 2.5% of god's honest truth.

The good news is that for weight loss you don't need that kind of precision. If your riding is fairly consistent you can ballpark it and then adjust based on what the numbers predict your weight should do vs what the scale says it's doing. 🙂

In the example you gave, I would be inclined to trust the Fitbit's numbers more but it depends a surprising amount on the bike, and on how fast you went. Also, some fitness things tell you how many calories they think you spent on exercise, and others tell you how many they think you burned during that exercise - the difference being your BMR. It probably took 3+ hours to ride 60 km (?), so your BMR would be a big contributor. I don't know if they're telling you different things, it's a possibility though.

MJW12020

That's really helpful, NorthCascades - thanks. The 60km took about four hours, but at the moment I just have my old commuter bike - a folding bike with 20 inch wheels, which is pretty slow. Probably takes more effort to get anywhere than a "proper" bike though!

NorthCascades

I'm thinking that must have burned a lot more calories than it would have on a road bike! Awesome effort! 🙂 👍

MJW12020

Thank you! The stops at the gym added to the fun :-)

sijomial

My calorie estimates have evolved over the last eight years or so. Looking back over that time.....

Spinning bike in a gym (no power meter) was pretty reasonable but a gross calorie estimate, correcting that myself to net estimates I would say for me it was pretty good.
Ramping up the mileage mostly on road hybrids I used HRMs and Strava app - perfectly reasonable for weight loss/maintenance but probably a bit on the high side.
MapMy suite of apps I found very high for everything.
Garmin bike computer with HRM input for a few years - again pretty reasonable. (Maybe the Strava and Garmin reasonableness was due to me having pretty dreadful aerodynamics and a low HR?)
Power meter equipped indoor trainer - very accurate if you did the maths manually or connected a bike computer but told big lies if you trusted their algorithm.
Comparison between HRM and accurate power meter indoor training showed steady state estimates by HRM entirely reasonable but a significant over-estimate for intense intervals.
Power meter equipped road bikes - very accurate most of the time. Very likely to be significantly under-estimates for winter riding when it's a struggle to stay warm.

For dieting or maintenance none of those estimates have the numerical power to disrupt my weight control, people get a bit too obsessed over accuracy. Someone would need a very large volume and a very large error delta over an extended period of time to be a big issue. Reasonable really is good enough for purpose.

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I don't use a Fitbit but is that 1500 just for the exercise alone or is that a reconciliation you see between Fitbit and MyFitnessPal? (The reconciliation isn't just exercise.)
If you are eating to your daily variable Fitbit goal I'd suggest simply carrying on and apply an adjustment if your weight trend indicates you need to.
Did you have the HRM going during the gym workouts? HR is a dreadful metric for weights workouts as it's neither cardio or steady state so a long way from where HRMs can be reasonable. Some wearables have a mode for weight training which should switch off using HR for calorie estimates.

MJW12020

sijomial wrote: »

(snip)

"For dieting or maintenance none of those estimates have the numerical power to disrupt my weight control, people get a bit too obsessed over accuracy. Someone would need a very large volume and a very large error delta over an extended period of time to be a big issue. Reasonable really is good enough for purpose".

This is a helpful perspective - thank you. While I am very good and diligent with recording my calorie intake and measure everything carefully, I am not so good as to eat only food I have made myself, so there is always some estimating in my counts anyway. So in the end variations on output will largely be offset by variations on input and, as you say, it doesn't really matter that much anyway.

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"I don't use a Fitbit but is that 1500 just for the exercise alone or is that a reconciliation you see between Fitbit and MyFitnessPal? (The reconciliation isn't just exercise.)"

I think the figure I derived from Fitbit is just exercise, whereas the HRM one will be both exercise and BMR combined, so that is going to account for a fair bit of the difference.

"If you are eating to your daily variable Fitbit goal I'd suggest simply carrying on and apply an adjustment if your weight trend indicates you need to".

Helpful advice, thank you.

"Did you have the HRM going during the gym workouts? HR is a dreadful metric for weights workouts as it's neither cardio or steady state so a long way from where HRMs can be reasonable. Some wearables have a mode for weight training which should switch off using HR for calorie estimates".

I have the HRM mainly for my group coaching workouts (they are designed to work together around the idea of getting a minimum number of 'effort points' each month). I also just use it as an indicator and one of my sources of motivation at other times. It doesn't connect with the Fitbit or MFP in any way and is not factored into my MFP figures.

Yes, my Fitbit has a mode for weight training.

Thanks!

mjbnj0001

I get results from using "Ride With GPS," my little stem-mounted cycle computer and MFP. All these numbers differ. I tend to believe RWG more than the others. As the pirates said in "Pirates of the Caribbean," " ... these is more like, um, guidelines ..." and that's how I treat them. I measure actual progress by the bathroom scale and live as best I can by the other guidelines.

heybales

MJW12020 wrote: »

Yes, my Fitbit has a mode for weight training.

So some devices have pre-set workouts for ease of starting for logging - but they just use the same HR-based formula that will be inflated for lifting or interval in nature.

Some of the Fitbit's do have a Weights mode that also happens to NOT use HR-based, but rather the more accurate METS database entry rate of burn. It'll still log HR info of course, just not use it for calorie burn.

How to tell?
On Fitbit, manually log a Workout Activity for exact same duration as the one showing on a prior day, using the Weights entry. Use a 3 am start time as this is temp.

Same calorie burn - great. You can delete the temp workout.

Very different calorie burn - not so good - but how far off?
Worth correcting in the scheme of daily burn, or weekly burn?
If very sedentary otherwise and this is 2 hrs daily for 6 x weekly - may matter.
If very active otherwise and this is 3 x weekly for 1 hr - probably no big whoop.

If you feel like correcting - just need to manually create a Workout Activity same start/duration time.
Fitbit is replace only system, so for calorie burn only the latest is used in the daily total, you can leave both in place.