Does a Fitbit or similar tracker make your activity level choice irrelevant?

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Merkavar
Merkavar Posts: 3,093 Member
in Health and Weight Loss

Does having a fitness tracker linked to your MyFitnessPal account make the activity level choice irrelevant?


For example say you set it to the top activity level and it gives you a target of 9000kj and setting it to sedentary gives you a target of 7000kj


would a fitness tracker adjust 9000 down to 7700 if set to highly active and adjust 7000 up to 7700 if set to sedentary?

Or is the adjustment from fitness trackers not working like this?

Replies

  • yirara
    yirara Posts: 10,613 Member

    Theoretically, but then the tracker needs to be set up properly. Say you have a higher than average heartrate and you track evercises with it. Then the tracker might give you very inflated calories for that. Or yours is lower than average. Now you get less calories for workouts. Some trackers also base calories on just your everyday stuff, and how your heartrate reacts to that. You watch a scary or super exciting movie and your heartrate is elevated the whole time. No, you don't burn more calories now.

  • age_is_just_a_number
    age_is_just_a_number Posts: 1,043 Member

    everything is an estimate.
    regardless of the calorie target MFP gives you and the calories burned your tracker calculates, what is important is tracking and reviewing the data as compared to your results.
    MFP may have you too high or too low a calorie target. You need to monitor your progress and adjust as needed.

  • Lietchi
    Lietchi Posts: 7,216 Member

    If you sync a tracker, yes, the chosen a level in MFP is irrelevant: in the sense that the end calorie goal will be the same (provided you have activated negative calorie adjustments).

    But there is a psychological aspect here, as well as taking into account your habits.

    For example, my own case:

    My activity level is quite variable from one day to the other. If I choose a higher activity level, I will see a higher base goal at the start of the day. But if it turns out I am not so active that day, I will end up with a negative calorie adjustment and at the end of the day I might suddenly find myself with too few calories left for dinner. I prefer to see the lower number and if it ends up being a more active day, I have bonus calories for a larger dinner and/or evening snack.

  • PAV8888
    PAV8888 Posts: 15,349 Member
    edited June 24

    Your understanding is correct if you have enabled negative adjustments.

    At the end of the day, assuming everything works correctly with the behind the scenes app integration, the MFP pre-selected activity level will be updated and replaced by the device's final estimate for the day.

    Whether the number proves accurate for you is another story subject to many caveats including the ones discussed above

    Whether you choose a low or a high activity level to start with is more of an individual thing.

    Most people will choose what @Lietchi suggests: start from minimum activity and add to it. It is also what I do these days with the non MFP app I log at.

    But while I was initially losing weight and for years after while still logging on MFP I was set up as active or very active because these levels were the closest MFP could get to my reality. And refraining from being encouraged to have huge meals at midnight because I had lots of calories was an appropriate goal for me.

    Just remember that, if you stop being active (i.e. if you go to bed, or couch surf, or what have you) before midnight, you will lose caloric adjustment during every minute MFP expects you to be more active than your device detects.

    Devices generally give 1.0*(sometimes possibly 0.95* if they detect sleep) BMR Cal / minute (usually Mifflin which is RMR strictly speaking) when they do not detect activity. MFP is also using Mifflin as their base estimate. Search for MFP BMR on web and you will find a link to what the system uses.

    With the changes in activity multipliers MFP appears to have made in late 2024, I believe that now even the lowest activity level starts at (1.4* BMR Cal) as your daily estimate

    So when you wind down at night you're looking at a minimum reduction to your positive adjustment till midnight running at (0.40 * BMR Cal / 1440 * minutes left to midnight). Minimum because the number will be higher if you're set at a more active level on MFP.

  • Merkavar
    Merkavar Posts: 3,093 Member

    Thanks all

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