BMR/NEAT/TDEE

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shannonfenske
shannonfenske Posts: 2 Member
in Food and Nutrition
MFP has calculated my daily calories at 1675. However, my BMR (calculated with multiple formulas on multiple sites) is 1886-1908. TDEE is calculated at around 2500. Why is MFP telling me to eat below my BMR?

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  • wunderkindking
    wunderkindking Posts: 1,615 Member
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    Because you told it you want to lose about 2 pounds a week and that means they're taking off a thousand calories/day. MFP is JUST a calculator.

    That said, eating below BMR isn't going to kill you and is not actually dangerous. It is a number you can ignore, beyond recognizing that you burn those calories even if you're in a coma and to not try to exercise off every calorie you burn in exercise or otherwise.
  • janejellyroll
    janejellyroll Posts: 25,763 Member
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    What drives your goals on MFP is how much you tell MFP you want to lose each week. If you tell MFP you want to lose two pounds, that will require a deficit of 1,000 calories a day. Unless you're very overweight, that will generate low calorie goals.

    There's no inherent problem in eating below your BMR, providing you aren't creating an excessive deficit.

    For many people, two pounds a week is too aggressive of a goal. Choose a more reasonable goal and you'll get calorie numbers that are closer to your TDEE (the truly relevant number for weight loss) while still being in a deficit.
  • heybales
    heybales Posts: 18,842 Member
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    Well below your BMR just means you likely don't have the amount of weight to lose to support the amount of deficit you selected.
    To keep it reasonable and sustainable anyway - people do extreme all the time. Again and again and again....

    Now, that eating goal is ONLY on days with no exercise, since that is not accounted for prior.
    You do more, you should eat more.
    Obviously do you less, sure better eat less.

    MFP uses the Mifflin BMR calc BTW, so you can do exactly the same math and see what happened.

    Without actual figures, it appears you may have selected Sedentary, and maybe 750 deficit.
    Reasonable amount for 30-50 lbs to lose.
  • Jthanmyfitnesspal
    Jthanmyfitnesspal Posts: 3,522 Member
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    If you want to explore the basic formulas used "under the hood" by MFP, you can go to this web site

    https://www.calculator.net/calorie-calculator.html

    They are based on population averages, so there is room for personal variation.

    I've said this many times: No matter what you do, weight loss is a slow process and weight maintenance takes the rest of your life. A thing to consider is what percentage deficit you can maintain comfortably for whatever time it will take you to lose the weight.

    Example: For me, it's about 25%. My sedentary TDEE is close to 2000kcals/day, so my weight loss plan (which I revisit from time to time) is 1500kcals/day plus additional to compensate for exercise. It just happens that omitting 500kcals/day gives 3500kcals/week which has been determined to be approximately equivalent to losing a pound of bodyweight per week, which is about what I observe when I get it right.

    Best of luck!
  • cwolfman13
    cwolfman13 Posts: 41,868 Member
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    shannonfenske wrote: »
    MFP has calculated my daily calories at 1675. However, my BMR (calculated with multiple formulas on multiple sites) is 1886-1908. TDEE is calculated at around 2500. Why is MFP telling me to eat below my BMR?

    MFP is just a calculator that is doing the math as per your stats and whatever you selected for your desired rate of loss. This would suggest that you selected a rate of loss that is overly aggressive for your stats.

    You can also customize your calorie target to whatever you wish. I only briefly used the MFP NEAT method and switched to TDEE once my exercise became a regular thing as it was just easier for me. I just lopped off 500 calories from my estimated TDEE and that worked just fine.
  • shannonfenske
    shannonfenske Posts: 2 Member
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    Thank you all for the insight. I started with about 125lbs to lose and have lost 48lbs. The past month, though, I've been at a complete plateau so I started looking into it further. I see many resources saying it's terrible to eat under BMR as it can cause your metabolism to slow too much.
  • cmriverside
    cmriverside Posts: 34,081 Member
    edited July 2021
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    shannonfenske wrote: »
    Thank you all for the insight. I started with about 125lbs to lose and have lost 48lbs. The past month, though, I've been at a complete plateau so I started looking into it further. I see many resources saying it's terrible to eat under BMR as it can cause your metabolism to slow too much.

    Re: the bolded part - Not so much true when you have 70+ pounds still to lose.

    It can become an issue when you get closer to a healthy weight.

    I'd leave it at the, "Lose 2 pounds per week," for now since you have so much extra weight. the 1600-1700 also does NOT include the calories you get for exercise - which TDEE calculators do include as part of your projected calories.

    Here, an explanation from the HELP section:

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

    This is helpful:

    cfpqwo9vvrsi.png

  • heybales
    heybales Posts: 18,842 Member
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    shannonfenske wrote: »
    Thank you all for the insight. I started with about 125lbs to lose and have lost 48lbs. The past month, though, I've been at a complete plateau so I started looking into it further. I see many resources saying it's terrible to eat under BMR as it can cause your metabolism to slow too much.

    Looking at the last 4 wk stretch of time where you were losing about the same amount weekly (don't count like the 1st week of big slowdown), how much did you lose on the scale in total for 4 wks?

    According to your food logging, how much did you eat in total during that same chunk of time?

    Weight change x 3500 / days of change = apparent deficit or surplus to TDEE.

    Obviously your TDEE changes - seasonal activity levels, weight lost means moving less, workouts change, ect.

    But it's still a good indicator of what your TDEE was during that time, and allow thinking about what may have changed.

    Because if you were an inaccurate food logger for instance, that wouldn't stop instantly and wipe out a deficit that had been working up to that point, unless foods changed, perhaps along with new method of logging exercise, or the workouts, or other stresses.

  • Jthanmyfitnesspal
    Jthanmyfitnesspal Posts: 3,522 Member
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    shannonfenske wrote: »
    Thank you all for the insight. I started with about 125lbs to lose and have lost 48lbs. The past month, though, I've been at a complete plateau so I started looking into it further. I see many resources saying it's terrible to eat under BMR as it can cause your metabolism to slow too much.

    Being on a calorie deficit for a long time can reduce your TDEE somewhat (a process called "metabolic adaptation"), but it's a small effect that can be countered by staying active.

    So long as your caloric deficit is sustainable for you, I suggest you stay the course, monitoring your activity level with something like a fitbit or step counter. Staying active in your daily routine and having some regular exercise periods can really help.

    Best of luck!

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