NIH's Body Weight planner and MFP discrepancy.

GigiAgape1981

I am in need of help in determining my activity level. When I enter my stats into MFP my maintenance # for lightly active setting is 1700 calories. When I do the same thing on NIH's website that number is 1813 calories for the same setting. Why such big difference? I tried using an activity tracker(Fitbit) but because I stand for a good part of the day 6-7 days ( 8+ hours) working with my hands(cooking, washing dishes, folding laundry) without taking steps or taking very few my step count and TDEE # is low at the end of the day unless I go on a walk. It's logical to me that my body burns more by standing rather than by sitting or sleeping and Fitbit counts lack of steps as that.

cmriverside

Best explanation is here (on "Help" at the top of any page, then "Using the App")

https://support.myfitnesspal.com/hc/en-us/articles/360032625391-How-does-MyFitnessPal-calculate-my-initial-goals-

PAV8888

Fitbit tends to underestimate activity that does not involve movement. You're correct that you're burning more energy by standing as compared to sitting, though depending on the type of activity this may be a relatively small discrepancy. Though probably enough to bump you up a category.

The mistake you're making is that you're considering all these estimates as much more than a starting point.

Your apparent results will depend on much more beyond nailing your starting estimates. Your food intake logging is even more important and how you evaluate progress (weight trend, weight trend, weight trend vs scale weight) may affect perceived results even more.

Furthermore the meaning (and implicit physical activity multiplier) used by various sites is different. Because the definitions are different and what is counted is different.

MFP is not including deliberate exercise and lightly active is a physical activity multiplier of 1.4x BMR. To which you would then add your deliberate exercise to get your daily caloric expenditure.

If you look carefully through the NIH website you're using you will see the multiplier that is being assigned and if you click on it you will be able to change the underlying estimates that are going into it and or get suggestions on how to evaluate your own multiplier. You might or might not have to click on expert mode for that.

Not sure if you're trying for maintenance or to lose weight. And how much you have available to lose if indeed you're trying to lose.

So all I'm going to suggest is that for most people with a tdee below 2500, goals beyond 500 Cal exceed 20% of their tdee. And 20% is already a fairly aggressive intervention.

Beyond that pick your goal, apply it for a time period (usually at least 3 weeks when not dealing with monthly hormonal fluctuations, 4-5 weeks if thus afflicted 🤷🏻‍♂️) compare expected results with actual weight trend results and adjust!

GigiAgape1981

Thank you so much @cmriverside and @PAV8888! Very helpful 👍