So how accurate are calories lost on exercise?

misssamrogers

Hey!

I know this has probably been asked loads but I'm getting a bit confused with information overload....not a bad thing just taking too much brain power to filter this all though!

How accurate are the calories lost? I've just done les mills grit strength followed by body attack, and apparently used 800ish cal. I mean that's awesome if it's true and I did push my self....but really? Should I eat these back?
Still getting to grips with this stuff!

nutmegoreo

I would start with eating about half back. Calorie output, depending on where you are getting that number is frequently inaccurate. I do find my Fitbit more accurate than the estimates by MFP. You do want to make sure you are eating enough to fuel those workouts, so start with 50%. After several weeks, see what your results are an adjust accordingly (if losing too fast, increase the percentage; if too slow, drop the percentage). I know faster sounds better, but in regards to overall body composition, energy levels, amounts you can eat in maintenance, etc. it is better to lose a bit slower.

I answered a bit more than your question, but many people get so focused on getting to goal that they fail to plan what they will do once they get there. I hope some of this helps.

Nicklebee93

It depends how much you weight... An obese person doing about an hour of exercise can lose 500 cals pretty easily... But someone like me, at 140 pounds, i probably only burn about 150-200 (and thats kind of generous).

Most people follow a rule of eating back about 50%-75% of what MFP claims you burn. I personally eat about 1,300-1,500 cals a day and don't eat anything back. It's just not worth it, i don't burn as much as others anymore.

sijomial

@n1cholee93
Fitness is a far bigger factor than weight.
Sure a big person doing exactly the same (weight bearing) exercise as a small person will burn proportionately more but fitness determines the intensity and duration you can maintain that intensity.

As an example I can burn at an unusually high rate as I'm very fit but a friend of mine who is 20lbs lighter can produce 30% more power than me and for much longer than me as he's ultra fit.


OP - exercise where you have to estimate intensity rather than use actual metrics (distance walked or run for example) are going to be very rough estimates. 800 calories in what duration? In an hour - very dubious!

Unless you are a very frequent exerciser then exercise accuracy isn't really anywhere near as important as food logging accuracy.

Should you eat back exercise calories as a principle? Yes - that's how this site is designed.
Just be sensible/consistent and make adjustments based on results

silico

n1cholee93 wrote: »

It depends how much you weight... An obese person doing about an hour of exercise can lose 500 cals pretty easily... But someone like me, at 140 pounds, i probably only burn about 150-200 (and thats kind of generous).

Most people follow a rule of eating back about 50%-75% of what MFP claims you burn. I personally eat about 1,300-1,500 cals a day and don't eat anything back. It's just not worth it, i don't burn as much as others anymore.

I agree with the above, as a safety net only eat back 50-70% of the estimate from mfp. This covers observation bias, errors in MFP's calculation for some exercises and the fact it is never 100% accurate for any one person.

misssamrogers

Thanks for all your replies. I'm gonna start by eating back 50% of my cals mainly because I snack a lot at work (nurse always on my feet) although I have found I'm actually quite full after snacks then lunch so should maybe cut done on the snacks.

I weigh 155 looking to be around 135. 800cal is from 1.5hrs of strength and cardio. Fitness is probably at a below average level if I compare to what I see in the classes, but I am determined to get there

LazSommer

Use a heart rate monitor or ignore MFP exercise values.

Nicklebee93

@sijomial
yeah of course. But considering the OP asked this question i don't think they're at that athletic point yet. It's a lot more difficult for someone my weight to burn that. 500 cals in an hour? I think i'd die before i got to that point... I'm just meaning in general, for an average person, it's a lot more easier for someone who is bigger to shred weight in a moderate/shorter amount of time.

Someone who is in peak condition (in my opinion) riding their bike for an hour at 15* MHP to burn 500 calories and an obese person can do that in an hour. Well that's a mighty big difference? Maybe it takes less, i don't know, it's just what others have told me on here. I'd love to find a way to burn that kind of calories.

DoneWorking

Whatever MFP tells you, go for half.

sijomial

n1cholee93 wrote: »

@sijomial
yeah of course. But considering the OP asked this question i don't think they're at that athletic point yet. It's a lot more difficult for someone my weight to burn that. 500 cals in an hour? I think i'd die before i got to that point... I'm just meaning in general, for an average person, it's a lot more easier for someone who is bigger to shred weight in a moderate/shorter amount of time.

Someone who is in peak condition (in my opinion) riding their bike for an hour at 15* MHP to burn 500 calories and an obese person can do that in an hour. Well that's a mighty big difference? Maybe it takes less, i don't know, it's just what others have told me on here. I'd love to find a way to burn that kind of calories.

@n1cholee93

Don't get what you are driving at in your last paragraph - remember large =/= obese.
Bigger people also need to lose weight quicker to lose the same PROPORTION as a smaller person.
Weight has very little to do with calorie burns on a bike as it's not a weight bearing exercise. Those skinny pro cyclists are tiny but can burn twice the calories I can.

Think you are massively over-stating what it takes to burn calories.
"But someone like me, at 140 pounds, i probably only burn about 150-200 (and thats kind of generous)."

At 140lbs if you run at 6mph you will burn approximately 264 cals in half an hour. That's not really that high a fitness target.

NorthCascades

n1cholee93 wrote: »

Someone who is in peak condition (in my opinion) riding their bike for an hour at 15* MHP to burn 500 calories and an obese person can do that in an hour. Well that's a mighty big difference? Maybe it takes less, i don't know, it's just what others have told me on here. I'd love to find a way to burn that kind of calories.

Burning 500 kCal per hour on a bike means you've put out an average of 138 watts.

Anybody with enough aerobic fitness to keep turning the pedals for an hour should be able to do that, and will find it somewhere from easy to moderate.

Nicklebee93

@sijomial
im not sure we are fully understanding one another. That calorie burn is for a 140 pounds person, right? What happens when i drop it down to 120? I lose calories. So how does weight not play a role? I'm not saying a person can't burn a bunch of calories. I'm meaning when it comes to MFP they normally over estimate. How does it know how hard you're working? How many breaks you took? It's just giving you an idea..

But i'm not going to argue anymore.. Like i said i don't think we're understanding one another and im not going to keep spamming the OP's question.

OP i hope you do well! If you start to lose too much or too little you can always tweak what you're eating back. Goodluck!

robertw486

I never use MFP estimates. They are based on averages and often use "windows" for pace and such that allow error.

Much like @sijomial I find that the best thing to do it research and figure out what is reasonable for your size and exercise intensity. Though many here seem to have focus on being cautious towards weight loss, having poor estimates can just as easily mess people up in that respect as well.

Being that fitness level is often subjective with many types of exercise, I found that running/biking/cardo output measures are often a decent way to gauge workload and at least get people in the ballpark for other types of exercise. Heart rate monitors might help with some exercise types, but that varies as well.



Being that we can't gauge how hard another person is working without some type of speed or other measure, stating any basic rule to apply is tricky. If I only ate back 1/2 of my exercise calories that MFP suggests, my workout from yesterday would be skewed to me creating at deficit of almost 600 calories, since the MFP default is low for my fitness level on the elliptical machine I use, which has a better power measure. For the next person the estimate might be close. For a very fit or unfit person it would be farther off in either direction.


@misssamrogers For your size and that time frame, I would say 800 calories is more geared towards a higher fitness level than you seem to think you are at, but keep in mind that without a measure towards something easier to calculate, that can be hard to pin down. As an example if you knew for sure that your workout was at a higher cardio intensity than you say, running 5 MPH for an hour, you have a better gauge for comparison.

You can also often find MET value or perceived exertion charts, that when used with some online calculators, should give you at least a ballpark range of what is reasonable. The one below is based on studies and models for walking and running, but if you do either it might give you a comparison of sorts.

exrx.net/Calculators/WalkRunMETs.html

sijomial

im not sure we are fully understanding one another.

Think you are reading to respond rather than reading to understand.

That calorie burn is for a 140 pounds person, right? What happens when i drop it down to 120?

Yes - if you do exactly the same (weight bearing) exercise then yes your burn will reduce.

So how does weight not play a role?

Read my post again - I said fitness is a bigger factor than weight. I didn't say weight doesn't play a role.
So a fitter person at 120 pounds will be able to exercise at a greater intensity and burn more than an unfit 140lb person for example. Run further or run faster for same duration.

I'm not saying a person can't burn a bunch of calories.

You actually said "An obese person doing about an hour of exercise can lose 500 cals pretty easily... But someone like me, at 140 pounds, i probably only burn about 150-200 (and thats kind of generous)."
I pointed out that is inaccurate. Even with very moderate fitness levels at your weight you can burn far more than that.

I'm meaning when it comes to MFP they normally over estimate.

Maybe. Not universal though. That's why I would say be selective rather than apply a blanket percentage cut.

How does it know how hard you're working? How many breaks you took?

Agree - see my first post regarding exercises where you have to estimate intensity.
For exercises that have empirical measures (running for example) MFP actually knows enough (weight, distance) to make good estimates.