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Why You Shouldn’t Trust Calories Burned on Exercise Machines

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Why You Shouldn’t Trust Calories Burned on Exercise Machines

You’ve just spent an hour on the treadmill, and the number on the screen tells you that you’ve burned 300 calories. Do you believe it? How did it get that number?

Your treadmill got that number the same way that the EPA gets gas mileage numbers: estimations and averages. Scientists had a lot of people run on a treadmill hooked up to a mask that calculated the amount of air they breathed, then used that to estimate the amount of calories were required to do the effort. Then they got an average over the sample and put that average into the treadmill, which spits out a number based on how much you weigh and how fast the drums were turning.

This number is pretty good … if you’re close to the average and do everything the way the people in the tests did. But did you?

Do you weigh what they weighed? Did you put your hands on the rails? Do you have the same ratio of fat to muscle? Did you work as hard per minute?


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The number on that treadmill is probably wrong as it relates to you and not the testers (unless you are very close to the average and do everything the same as the testers did). But the more you deviate from the mean, the less likely the mean is an accurate way to predict your actual calorie usage. Let me show you what I mean with gas mileage.

I own a car. Can you tell me how much gas it uses on my way to work? According to the EPA, the average fuel economy for a car in the United States is 24.6 MPG combined cycle, so would that be a pretty good guess? It would be a terrible way to guess! What kind of car I own, how I maintain it, what kind of driving I do on my commute and how much of a lead foot I have all matter if you want an accurate guess of how much gas I use during my commute. Even if I told you my car has four doors and weighs 3,500 pounds, it could be a Prius or a BMW M5. I’ve owned both and let me tell you, there’s a 4x difference in gas bills for the exact same commute.

And this is not just a math problem. According to a 2014 study by Fenzl, Bartsch and Koenigstorfer, the harder we think a workout was, the more we will eat afterward. For this study, the researchers told half the participants they were working out in a “fat-burning zone” and the other half in an “endurance zone,” even though the exercise was of the exact same intensity and duration. The participants were then offered water and pretzels. The participants who were told they were “working harder” ate more pretzels than those who did not.

The more we think we exercise, the more we eat. So don’t let the number on that treadmill fool you. “I exercised so I deserve this,” is one of the most dangerous thoughts you can have if you are trying to lose weight.

Written by Coach Stevo, the nutrition and behavior change consultant at San Francisco CrossFit. He is a Certified Strength and Conditioning Specialist, holds a BA in Philosophy from the University of Chicago and an MA in Sport Psychology from John F. Kennedy University. He teaches habit-based coaching to wellness professionals all over the world and he contributed to Intervention by Dan John in 2012.

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  • deckerp

    My treadmill knows how tall I am, how much I weigh, the incline of the ramp I used, the resistance I used, the speed I ran at, the time I spent each speed.

    Read that again and notice how many times it says “I”. This is giving me my numbers and not the average gas mileage for some average care. It’s giving me the gas mileage my exact car gets in the weather conditions I was driving under driven the way I drive.

    I guess I’m saying I feel safer about its guesses than most people’s facts. (Star Trek reference there for you Trekkies).

    • Kathryn Lucy

      I definitely agree. If it’s a personal treadmill and it has all your stats it’s definitely going to be a lot more accurate. However if you just start exercising at a machine at the gym and don’t even enter your weight or age or anything it definitely seems like it could be inaccurate

  • Shelly McWhorter

    On most days, I do not eat back my calories. But I try to only have a cheat meal or day when I do exercise. I just consider anything I exercise as bonus calories burned that I bank that will get me to my goal faster.

    • Foodahz

      Bank it, Shelly!

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    • cecilia21

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  • mixedandlovely

    I exercise just for my health.. I never eat my calories back that would be a waste of time to me!!!!

    • Paranormal Skeptic

      You’re generally doing this, as long as you net ~1200 minimum. If you burn 10,000 calories a day, and only eat 1500 calories, you’re setting yourself up for failure.

      • Lea

        How does one burn 10,000 calories in a day?

        • Easy. Use a chainsaw to chop off the belly.

        • mixedandlovely

          Right how does one?? Sign me up…

        • Paranormal Skeptic

          Bicycle touring. Or, running a marathon.

          Of course, I was exaggerating a bit to make a point. Even if you burn 5000 calories in a day (Which is very easily doable), and only eating 1500, you’re still setting yourself up for failure.

          • Lea

            Of course.

        • Ryan Mitchell

          You morph into Michael Phelps and train for the Olympics again. Bruce Jenner could probably help you with that. I did a workout 1 mile run, 100 pullups, 200 pushups, 300 air squats, and finished with another mile. Burned roughly 1200 cal. So just repeat this workout 3x daily and you should be there (you’ll get slower each time and hence burn more

          • Lea

            You mean Caitlyn Jenner?

            Also 3 x 1200 = 10,000?

          • Ryan Mitchell

            Maybe. 1200 for first workout. The next time will take what…45 min longer? A repeat of that (I’d be dying just to finish the second time) would probably take 2 hours longer. This would become a 5-6 hour gruel test that would likely put you into rhabdomyalysis. I won’t try it. You can and post the results, I’m quite interested in it now. 🙂

          • Lea

            Naw dude 😐 Naaaaaaaw. You keep it.

      • mixedandlovely

        That would be good if I did burn those many!! But I don’t. ..I work out 4 days a week 30 to 40 minutes …I tried increasing my intake by 300 it was fine until 2 weeks ago gained 2 pounds back after changing over 6 months ago

        • Ryan Mitchell

          2 lbs could be normal weight fluctuation. Depends on what you do for those 30-40 min. If you do sprints outside you won’t have to worry about those 300 calories. Good job on excercising!!

          • mixedandlovely

            I do Cardio .. Thanks Ryan Good information!!!

      • Allison

        Obviously not 10000 in one work out. The “average” person burns 2000 calories a day. So you will most likely hit 10000 just from walking around.
        Come on people….

  • I eat back all calories reported on the Open Stride machine, and it’s pretty accurate.
    I hope I can afford a Fitbit tracker.

  • Debbie Vietzke

    I realize this article is about machines which I don’t currently use. But I thought I”d add my thoughts anyway.
    I don’t exercise to burn calories and I don’t add the calories that I do burn to my daily calorie goal. I exercise, pretty much all walking and housework, to relieve arthritis pain and keep my muscles as functional as possible.

  • budiamond

    That, and most exercise machines (and MFP too) report gross calorie burn as opposed to net calorie burn. So a good percentage of those calories you’re logging? They’re already being burn as part of your RMR.

  • S Lloyd

    I Am using three different apps to track my steps and physical activity. They are all giving me different numbers. I can’t rely on them to determine how much more I can eat because it has significantly reduced my progress towards weigh loss. Could you give a scale on or suggest a site that helps those with a high BMI to determine their daily calorie intake. I am trying to figure out if I should be adjusting my calorie intake for every pound I lose. What is the safest calorie range for significant weight loss?

    • TheLady

      Your best bet is to visit your doctor and a nutritionist to find out what calorie range is best for you personally, as they will have all your personal information. A nutritionist will also recommend the best types of foods for you to get those calories from and what amounts and percentages of fats, protiens and carbs you need daily for good health and weight loss.
      Speaking *very* generally the common suggestion is consuming 1200 calories a day for women and 1500 calories a day for men for weight loss. Additionally, it is not recommended that men or women consume below 1000 calories a day without strict medical supervision. To few calories can throw your body into starvation mode and it’s unhealthy.

      I personally don’t adjust my calorie intake according to how much I’ve excercised. I consider any extra calories burned as a bonus.

      • james pogrebetsky

        1500 for a man? What, a 125lb “man?” That’s starving yourself. Maybe if you’re bedridden

      • Lea

        1200 is too low for anyone. Haven’t we talked the “Magic 1200” to death yet? Why are people still using that as a goal?

        • Jennifer Cotton

          1200 is not too low for anyone. As a very short woman under 5 ft tall trying to lose weight, anything higher and I gain. If anything I need a smidge less than 1200 to lose and around 1300 to maintain. Sucks to be me but that’s the way it is for some people.

          • Helen Hines

            I agree, I’m 5’1″ and I can’t eat more than 1200 or I’ll gain the weight back. Once I’ve reached my goal weight I could eat more to maintain the weight but to lose it can’t be more than 1200 calories aday.

      • Ryan Mitchell

        Yep those numbers are way low. MFP gives me 2400. I already lost too much the first week as is. At 1200 I would probably be in a coma especially with the heavy weight training etc.

    • Paranormal Skeptic

      Experimentation is about the only way, to get a real accurate number.

      Reduce calorie total, see if you maintain. If you lose, it’s low for TDEE. If you gain, it was high. If you maintain, you found it.

      Do the same for exercise calories. Track using the provided numbers on one of your resources. Do you lose? Gain? Maintain? Adjust with a multiplier as needed (I use .6 for Runkeeper’s calorie estimation, and it seems to work for me).

  • Ryan Mitchell

    Wow it’s interesting to note that most of you don’t eat back your calories. I often do high intensity interval training (crossfit) and simply log this time as a slow jog. More than likely I’m burning way more than what the app estimates. In addition, I do almost almost all my Cadio other than row on the pavement or lifting heavy weight. I don’t log any pure strength workouts. Should you eat back those calories? That depends on the intensity of the workouts and how fast you want to lose weight. I think a good rule of thumb is to slightly overestimate your calories from food and slightly underestimate your calories from working out. Then try to fill those calories with good healthy food. Allow yourself a treat sometimes because no one is perfect but stay in your calorie zone. Happy weight loss people!

    • Melissa

      A good rule I heard from my doctor was when your calculating your calories in add 10% because itll give you a more accurate estimation.

  • My Name Is Oliver Queen

    You shouldn’t trust exercise machines calorie burn because they may be over-estimated? That is hilarious coming from MFP who estimate calorie burns double or triple what the machines give!!!! The more I read the blogs and the forums, the more it becomes apparent that MFP is setup for people to FAIL rather than succeed especially with the “advice” given on the forums by posters claiming that Doctors know nothing about healthy diets, etc.

    MFP is becoming the laughing stock of the weight loss community in a big way. If I could export my data in to a different app, I would do in a heart beat!

    • Ryan Mitchell

      How is MFP responsible for people that post or blog on here? If you do not take the time to research what people blog about on here before beginning it then you are an idiot. Are there better weight loss programs? Of course! I could get a full nutritional analysis done by a physician using $600-1200 in medical tests and exam fees. I could order pre built meals shipped directly to my house. MFP may not be all that but it’s free and it works, and that’s what matters. Haters gonna hate though.

  • Jonathan Y.

    This article is terribly misleading:

    (i) First and foremost, the science behind these figures does take into account your age, height and weight, so it can make a (very) rudimentary guess as to your body’s composition. Certainly, the mean applies to people of your weight (yes to “Do you weigh what they weighed?”), and we can also assume a weak-positive answer to “Do you have the same ratio of fat to muscle?”.

    (ii) The article only takes into account a very specific type of machine (namely, the treadmill). One cannot trick other types, such as ellipses or cycles, as easily, as they could be measuring the energy spent to preform the exercise (‘work done’) directly. Only the high-end ones measure instantaneous power (“Did you work as hard per minute?”), but even the very cheap ones can tell what resistance you were working against, and at what rate you were working. It’s true that people’s bodies’ efficiency (the amount of energy lost in conversion or inner-body mechanics) does vary, but the range of that variation is very limited (about 5-10% of energy spent), even more so when the maker of the workout-machine knows his audience. Not to mention, many models out there could also be relying on other metrics, such as heart rate, to adjust the figures they present.

    (iii) To conclude, other parts of the article are simply argumentative, ad absurdum. (“Did you put your hands on the rails?” To reply in kind, I imagine the reading might be even less accurate if I set the treadmill in motion and just go have a margarita while it’s running.) They only serve to confuse the inexperienced reader and paint a one-sided picture.

    I actually value coach Stevo’s contributions to this blog, that I’ve seen, and find them very well thought-out. A shame to spoil that record with this poorly justified proposition.

    • Catherine

      Exactly! This is almost as bad as the article from a couple days ago titled, “3 Ways Your Breakfast Is Sabotaging Your Weight Loss.” In that article, they compared grams to calories to try to prove their point in an extremely misleading way. The picture of the graphs is attached. The left pie chart shows percentages by GRAMS. The right pie chart shows percentages by CALORIES. Ridiculous!

      • Tara Sampaio

        I believe that the numbers on the treadmill are not reliable due to the fact that it does not measure or take into account your BMR nor does it take into account the metabolic rate of minorities

        • Dawn Wolte Ezell RN

          I didn’t know “minorities” have a different metabolic rate…

        • HotGaymes

          Is this a joke? YOU take into account your BMR… the treadmill tells you (the accuracy of which is questionable, but neither here nor there in this comment) how much you burned while on it. It’s not gonna tell you how much you burned from your BMR while you were sitting in the other room, now is it? I think a simple pen and paper can add the two then subtract from calories eaten… I have an excel sheet if even that’s too complicated.

      • Helen Hines

        If I can’t trust what the machine indicates the amount of calories burned what source do I go by? How can I estimate how much I’ve really burned?

        • Rosemarie

          Very good question. The gym treadmill says after running 45 minutes i burned 310 calories. But MFP tells me i have burned 375 cals. What do i believe?

    • Dawn Wolte Ezell RN

      I believe this article is correct because I don’t know about your treadmill but mine is brand new and not cheap but it does not ask my weight or my age…

  • If you think the machines are giving you bad numbers, running outdoors using a GPS watch or phone app is even worse with at least 1/2 dozen more variables thrown in. Temperature, humidity, wind speed/direction, running surface, slight inclines/declines that GPS watches and smartphones usually don’t pick up, etc. These can all greatly affect your calories burned.

    • Chantal

      I use a TomTom GPS watch that tells me all that info. What the terrain was, gains and losses in elevation. And Runtastic will ask you what kind of terrain you were running and logs the weather once your location is turned on on your phone. Plus I have a heart rate monitor attached to both. Apart from getting my VO2 max, its fairly accurate.

      • So the Tom tom can pick up subtle elevation changes like 100 foot gains over a mile even in heavy tree cover? Pretty impressive. I have checked my Garmin against a mapping grade Trimble GPS and it is not close. Even if it does pick that up, does it use it in the calories burned calculations.? With my Garmin, I run a 5 mile course in the mountains with a 1,200 foot elevation gain and I run a 5 mile course here in the coast with less than a 50 foot elevation gain, both in about the same time, and the calories derived is nearly the same. Not to mention the effect of running at elevation itself. Also, I understand the phone can record the temperature, humidity, wind, etc., but does it use that in the calories burned calculations? Where is the weather data coming from? In some places, weather at the station in the valley is much different than that at elevation.

        • Nick Fergadis Giannakopoulos

          There must be something wrong with the GPS elevation data in the areas you run then.

  • cecilia21

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  • Heather Kelley

    This article only gives you problems. No solutions – except maybe – don’t eat back your calories

    • j_squared

      I thought the same thing. I was waiting for the solutions and they never arrived. Personally, I use a heart rate monitor and it does give me a different number from the treadmill – but in the opposite direction – I consistently burn *more* than the treadmill says, but it’s somewhat negligible. The largest difference I’ve had was about 70 calories.

      • Lauren Navarrette

        Here is a solution. Do the manual mode.you can input your own weight or close, it is always better to put in less weight than more because the less you weigh the longer the machine reads to burn calories, which makes relative sense. Try not to hold the rails as often as you can. If you are exhausted and worn down, best to either slow down to where you can easily catch your breath, or take a break on the tread and move on to another workout and come back later. Don’t move to eat back calories.

        If you weigh 120, input your weight as 110. Then you can guess about how many calories you have really lost and not worry that you held the rail for a few minutes to catch your breath or something. Is it 100%, no, but I have found better results from it.

        • Helen Hines

          I don’t understand your theory on the less weight part. How is it that by saying you weigh less than what you really weigh is going to give you closer to the accurate score?

          • Sophie Harms

            The more you weigh, the more calories you burn. I burn more calories on a treadmill in the same amount of time if I weigh 180 than if I weigh 170. So if you enter a weight that is less than your actual weight, the machine will reflect less calories burned than if you entered your real weight–thus negating some of the inaccuracy of the machine, which tends to overestimate (sometimes by a LOT) what you have actually burned. Lower weight programmed into the treadmill at the start of your workout, less calories considered burned by the machine, which compensates for factors like what Lauren mentioned above at the end of her comment. Does that make it clearer? Hope I could help.

          • Helen Hines

            Ok, I understand your point now and thanks for explaining it to me.

  • Alice Thresher MacKenzie

    I don’t think any program or estimator is 100% accurate as each individual has their own variables aside from height, age, weight etc. Some people have medical issues that affect their weight due to the medications they take. I was one of those people. Using MFP and a Fitbit I started a journey last February to take control of my health. I lost 53lbs so far just counting calories, changing the types of food I eat and drinking a lot of water. I have a coffee with no sugar just cream in the morning then water the rest of the day. On really rare occasions I may have a diet soda but my body no longer likes the carbonated drinks. I started baking my own desserts and growing herbs and vegetables the last couple of months. I was diabetic type 2, had very high cholesterol and tryglicerides when I started this journey. I take about 10 different medications a day and after years on this cycle I finally have lowered all but the tryglicerides to within or below the normal range. If in 6 months my levels are still like they were recently the doctor will cut out about three to four of my medications. I have mobility issues that at my heavier weight made basic exercises hard to do but recently I hit my first plateau which discouraged me at first but I took the next step and joined a gym where I do low impact strength and cardio training. I ride the bike for my cardio and did notice MFP estimates my calories burned cycling to be more than the machine but wearing a fitbit that actually deducts calories if MFP is too high I feel that the calories being logged are fairly accurate for me. I also lowered the calories that I allow myself a day to less than when I started this journey. Nothing is easy and no program is perfect but if you are diligent you can achieve a healthier lifestyle without having to spend a lot of money. Before I started using this free App I was told by medical professionals I was a prime candidate for lapband or gastric bypass surgery so needless to say I have been pretty happy with the MFP/Fitbit combo I chose to try. I am 5’4″, 53 years old and at my heaviest weighed around 282lbs. When I started using MFP I weighed around 275lbs. I currently weigh around 222lbs. Some people may think my weight loss is no big deal but since I became physically disabled 6yrs ago it is a huge deal to me!!

    • Drum randy

      Well done Alice!! This is a Hugh accomplishment and I you should feel very good about it. I just started MFP last Saturday so have just completed my fist week, you are ann inspiration. Thank you for posting you story.

      • Alice Thresher MacKenzie

        Awe…you are welcome!! It’s so nice to know I have inspired you!! Good luck on this new journey you are undertaking!!

    • Amy Neeson

      Well done Alice! Thanks for sharing your story. I bought a Fitbit recently and between that and the my fitness pal app I’ve lost over 3 kilos. Not sure what that is in pounds, I’m in Australia! 🙂 Keep up what you’re doing. Sounds like it’s working.

      • Alice Thresher MacKenzie

        Thank you so much!! It sounds like you are on the right track!! I wish you much continued success!!

    • Linda Taylor

      Well done! Keep up the great work. I agree I am off meds and gaining muscle. My goal is to lower my body fat and gain my health back. I use MFP and endomondo app, I am happy with the results I am getting. I eat my goal calories, at the end of the week I may have anywhere from 300 to 800 under my weekly calorie goals.

      • Alice Thresher MacKenzie

        That’s awesome!! Keep up the great work!! 🙂

  • nofdefc

    you lost me with me….. you used drive a Prius and a BMW.

  • Diana Hill Lovell

    So how does myfitnesspal “know” how many calories a certain exercise burns for your weight loss goals chart? Haha! It’s always an average unless you have a tailor made gadget.

    • Jennifer Cotton

      I use a heart rate monitor. Seems to work for me.

  • Sharon Cullen

    Like everyone else I wish you would have given us a solution. Currently I take the burn that the elliptical tells me and subtract 20% from it with the hopes that it’s a little more accurate, if not under ,my actual burn.

  • BekkyShambles

    I have a FitbitHR that knows my body fat percentage, height, weight, age, everything I eat, my sleep and activity patterns, and more. The elliptical at my gym and my FitBit are never more than 15 calories different in their burn estimate. I’m just saying… it may not be perfect, but it’s not some disastrous miscalculation that will completely deceive you and throw you off your plan. Some are more accurate than others, for sure! But we all knew that already, right? You’re always, ALWAYS making an educated guess. And that’s just fine. 🙂

    • Doc Happy Hollidays

      I should have read your post first because I basically just repeated it. I have a Fitbit Surge & a Lifefitness Eliptical and after a 60 minute workout, the numbers they give are almost identical..maybe a difference of 5% or less. It’s close enough & gives you the information you need to make educated choices.

  • Donna Keehn

    Jennifer, your formula doesn’t work for the person that is already at goal weight. When I inserted my figures into your formula (I weigh 110 lbs with 19% body fat), I got that I should be eating just 891 total calories a day. If I only ate that much per day, I would be dead. You need a minimum of 1200 calories a day just to keep your organs from shutting down and be still have enough energy for basic things like sitting and standing.

    • Jennifer

      Donna,
      You are correct. But I was posting to S Lloyd who is not at goal weight. If you are at goal weight you know what you had to do to get there, and what you need to do to stay there, but if you are like many of us who are wandering around in the dark, having a formula to figure these things out with is very helpful. BTW, this formula is not for the eat more, exercise more type of program. If that what you are into you need a lot more calories. I posted this formula because most beginners tend to be on the eat less exercise less type of program.

  • Wesley Edwards

    IDK, I figure most of it comes out in the wash. It’s about like people getting mad at statistics simply because they are statistics. I do try to give myself ample room between net calories and allowed calories just to be safe. Somewhere in that gray zone life happens and we just have to manage and live with the uncertainty.

  • Kim Williams

    All machines do vary depending on the make and model etc. You will never get a true reading of what calories you burn during a workout. I have a cross trainer at home and I use one at a gym and after an hour workout, there is approximately 150-180 calorie difference between the two, so I always go by the lowest. How do people get the exact calorie counts on food and drink, that must vary too. Everyone’s body burns differently, so I find it is best for me to find how my body works and how it changes in weight by monitoring my work outs and what I eat. It does work!!

  • Captain Jeff

    Ignore the numbers…the numbers on the treadmill, on the elliptical & especially on the scale. Eat right, strength train, do cardio…thats the only secret to losing weight. That and a helluva lotta determination. I lost 30lbs in 60days. The numbers didnt matter, what did matter is what i thought when i looked in the mirror.

  • Dennis Smith

    Can you spell G-U-I-D-E?!? Use the number(s) a guide not as absolute truth.

    • TheBelltower

      Exactly! Anyone who is overly concerned about a potential 10% disparity is missing the point. Keep exercising, while following the data and the results over time.

  • Tamh170obust

    well Im not changing how I do things, I do not have a fancy heart rate monitor my equipment allows me to put in my weight and age… and always tells me I have burned less than what MFP does so I figure on that number likewise if I put in my food and there are four entries for the same thing say 89 cal 98 cal and 100 and 115cal I go with 100 I go to the higher side within reason… so basically I round up my food intake and round down my output so I always ‘earn’ more than I give my self credit for

    • Doc Happy Hollidays

      You’re right – there is no reason to change anything. I have a fitbit surge which takes into account a lot of person info (age, height, weight, average heartbeat, etc) and the number if gives me (calories burned) is very close to the number I get from my eliptical which only takes into account my age & weight.

  • Mateasley88

    A good ending to this article would be some type of solution for the issue… is it better to tailor a calorie counter or smart watch to your own age/weight/bmi for more accurate results?

  • ubs

    Pointless… no idea how many cals I burned reading this drivel…