Burning less calories?

Hi All,

So. I’ve been working out since Sept 1. I use a Fitbit to measure calorie burn as it’s got a heart rate monitor. When I trained for an hour I would burn about 700-800 calories. Now, though I am doing more and lifting heavier weights and I’m only burning about 500.

Same goes for something as simple as walking. Walking 30 mins in the past Id burn about 300. Now, barely 200. Am I just getting fitter? Aka it takes me longer to build up a sweat or getting the heart rate up? I know the calorie burn from Fitbit isn’t really that accurate but even so it’s getting lower and is a rough gauge. Thanks for help!
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Replies

  • apullum
    apullum Posts: 4,838 Member
    How much did you weigh on September 1, and how much do you weigh now? It takes less energy to move a smaller body than it does a larger body, so if you weigh less, you will burn fewer calories doing the same exercise than you did when you weighed more.

    Your Fitbit's calculations seem pretty high, depending on what you were doing and how much you weighed.
    Walking calories are about 0.3*weight*miles walked, for example. In 30 minutes one can probably walk 1-2 miles depending on pace. However, without knowing your weight, it's hard to say whether those calorie burn calculations are accurate for you.
  • bdonahue12188
    bdonahue12188 Posts: 8 Member
    I weighed 230. Now weigh 213. I’m 5’9.5 Fitbit knows how much I weigh and my height.
  • apullum
    apullum Posts: 4,838 Member
    edited November 2019
    I weighed 230. Now weigh 213. I’m 5’9.5 Fitbit knows how much I weigh and my height.

    Your Fitbit calorie calculations are off. @cwolfman13 gave some good explanations for what might be happening.

    For a 30 minute walk, you're probably burning around 100-140 calories depending on exactly how far you're walking in that time.
  • anubis609
    anubis609 Posts: 3,966 Member
    Don't get myopic on calories burned that your fitbit gives you. It's not going to be accurate, but as everyone stated, you will burn less at a lower body weight, that's just the way the body works. Do note that you are burning calories, but exactly how much you won't know for sure. Instead, focus on what you can control, such as calories ingested and your performance. If you're lifting heavier weights and walking longer, those are positively objective numbers you can focus on that you can measure.
  • nytrifisoul
    nytrifisoul Posts: 500 Member
    I don't agree with some of the posters saying its impossible to burn 700-800 cals in an hour. I am considered obese for my height and weight but i am stocky. At my recommended weight at 8% body fat, i looked anorexic. I am going off topic......Anyway, i probably have better cardio then most people. Even after a few years not doing cardio, after 2 months of HIIT i can hold a constant 160-170hr for an hour. And i burn 800 cal easy.
  • sijomial
    sijomial Posts: 19,811 Member
    I don't agree with some of the posters saying its impossible to burn 700-800 cals in an hour. I am considered obese for my height and weight but i am stocky. At my recommended weight at 8% body fat, i looked anorexic. I am going off topic......Anyway, i probably have better cardio then most people. Even after a few years not doing cardio, after 2 months of HIIT i can hold a constant 160-170hr for an hour. And i burn 800 cal easy.

    Who said "impossible"?

    How are you measuring your calories burns while doing what exercise?
  • nytrifisoul
    nytrifisoul Posts: 500 Member
    sijomial wrote: »

    Who said "impossible"?

    How are you measuring your calories burns while doing what exercise?

    Polar H7 chest strap w/polar beat app. So far ive noticed Polar beat records the lowest calorie burn then every single online calculator ive tried. Bowflex TC100. I do intervals between 2.5 to 3.5 mph keeping my avg hr at 165 bpm.

  • NorthCascades
    NorthCascades Posts: 10,970 Member
    sijomial wrote: »

    Who said "impossible"?

    How are you measuring your calories burns while doing what exercise?

    Polar H7 chest strap w/polar beat app. So far ive noticed Polar beat records the lowest calorie burn then every single online calculator ive tried. Bowflex TC100. I do intervals between 2.5 to 3.5 mph keeping my avg hr at 165 bpm.

    The fact that it's the lowest number doesn't mean it's correct, it means it's lowest.

    Heart rate monitors don't have any special insight into how much energy you're using. They provide a clue in the right circumstances, but it's just a guess.

    See if you can get access to a bike with a power meter because this will be accurate for calories to +/- 2.5%. Unfortunately it tends to be an eye opening experience.
  • JenniferM1234
    JenniferM1234 Posts: 173 Member
    I’m 5’3” and 118-120 pounds. I know for a fact that 30 minutes of moderate treadmill walking, at my height/weight/age, burns around 90 calories. So unless you’re running at a full-out “gallop” for that same amount of time, I can’t believe it would be a lot more than 200 calories. 🚶🏻‍♀️🚶🏻‍♀️🚶🏻‍♀️
  • firef1y72
    firef1y72 Posts: 1,579 Member
    When I weighed 200lb+ and was very unfit (felt like I was dying when my hr hit 130), i could burn 700 Calories in 45min of zumba.

    Now I'm only 140lb and (according to some) super fit, I'm lucky if i burn 400 in the same class despite jumping a lot more.

    It's simply a consequence of being lighter and fitter, sometimes it bums me out. Especially as my PT is running a challenge right now to see who can burn the most calories in 45min (I dont stand a chance)
  • Lolinloggen
    Lolinloggen Posts: 463 Member
    Was the Fitbit new when you started? It also takes time for your Fotbit/garmin fill in brand of choice to get used to you.I am on my 5th HR wristband and usually the first three to four weeks of data kinda suck at the low and high end. In one case I even retired one as it never started working properly for me Just did not fit my wrist the right way.
  • nytrifisoul
    nytrifisoul Posts: 500 Member

    The fact that it's the lowest number doesn't mean it's correct, it means it's lowest.

    Heart rate monitors don't have any special insight into how much energy you're using. They provide a clue in the right circumstances, but it's just a guess.

    See if you can get access to a bike with a power meter because this will be accurate for calories to +/- 2.5%. Unfortunately it tends to be an eye opening experience.

    Well it may not be exact, but its close enough that i am eating back at least 75% of extra burned calories and i am still losing close to my weekly goal. I am not big on the science behind it, i just know that it works for me as i have lost a lot of weight the few times that ive gained it back, but that is my fault for not sticking to a healthy lifestyle for more then 3 years at a time.

  • jhanleybrown
    jhanleybrown Posts: 240 Member
    edited November 2019
    I don't agree with some of the posters saying its impossible to burn 700-800 cals in an hour. I am considered obese for my height and weight but i am stocky. At my recommended weight at 8% body fat, i looked anorexic. I am going off topic......Anyway, i probably have better cardio then most people. Even after a few years not doing cardio, after 2 months of HIIT i can hold a constant 160-170hr for an hour. And i burn 800 cal easy.

    It's definitely possible. If you are 200 lbs and run for an hour and do 6 miles, just under 800 cals. (.66 x 200 x 6). That's doing 10 min miles - far from an elite athlete!

    But if you are 120 lbs...to produce the same burn in an hour you'd have to run 6 min miles and go 10 miles. Which isn't elite, but it's pretty damn hard. So body weight plays a factor.