Eating Back Calories Given from FitBit

So according to mfp, at the end of the day, its showing a number in green.. usually a large number.. i do not log exercise, i just have.my fitbit synced to it. It seems like such a big number and i for one, dont really want to eat anymore and 2 im afraid ill gain.. any thoughts? Im not great at this stuff. :/
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Replies

  • WinoGelato
    WinoGelato Posts: 13,454 Member
    It would be helpful if you would provide some additional details.

    What are your stats: height, current weight, age, gender?

    How much weight are you trying to lose?

    What activity level did you choose?

    What calorie goal did MFP provide?

    How many steps does FitBit say you got?
    How many total calories burned?

    What sort of exercise and activity do you usually get? How typical is this level of activity?

    What was the exercise adjustment?


  • fuzacoza
    fuzacoza Posts: 33 Member
    WinoGelato wrote: »
    fuzacoza wrote: »
    You can remove your exercise cals from that. Personally I don't eat too far over my Metabolic Base Rate which basically is that GOAL figure to your left. That includes your energy needed just to be awake.

    You don't have to eat those back, you are on the safe side eating just your GOAL. Personally I will eat a max of 20% into my exercise gains.

    kpe460au5d4x.jpg

    No - this is basically all wrong. The number that MFP provides you is an estimate of your NEAT - which is your BMR (the cals you burn just being alive) plus an estimate of your calories from daily activity based on what activity level you chose. When you exercise and burn more calories than that you are meant to be eating those calories back to fuel your Total activity. FitBit provides a calorie adjustment which is representative of the difference between what MFP thought you’d burn and the total amount FitBit says you burn.

    Ignoring those completely means you are significantly under fueling your body, and thinking it’s good to try to be just at your BMR when you are clearly an active person? That’s just a recipe for failure.

    Eating 1800 ish calories and exercising off 1100 is the same as if you only ate 700 cals and did no exercise. Does that sound healthy?

    But you already adjusted your "GOAL" based on your activity and your goal target. Using a different calculator my BMR is 1785 cals.

    My Total Daily Energy Expenditure is 2953 using more specific activity input in that calculation, to loose weight the max will be 20% from that leaving 2362.00. 500 odd cals more that MFP.
  • fuzacoza
    fuzacoza Posts: 33 Member
    My TDEE was calculated to include bodyfat:


    Total Daily Energy Expenditure,
    Based on your stats, the best estimate for your maintenance calories is 2,719 calories per day based on the Katch-McArdle Formula, which is widely known to be the most accurate when body fat is provided. The table below shows the difference if you were to have selected a different activity level.
    puzxyqfgaa2p.png


    Maintenance:
    gc55y2oqgx48.png

  • counting_kilojoules
    counting_kilojoules Posts: 170 Member
    When I got my fitbit I synced it with MFP but I was getting more calories than I used to when I was logging my walking manually and since that had seemed pretty accurate I didn't think this was. In the end I unsynced it. I love it because it helps keep me accountable for physical activity but it wasn't helpful when it came to calorie counting. In the end I just upped my activity level (because I'm more active now but if that wasn't the case I'd have just gone back to manually entering every walk instead.)
  • WinoGelato
    WinoGelato Posts: 13,454 Member
    All of the calculators and formulas work slightly differently. What does your FitBit say your total calories burned is? That is also a representation of your TDEE and in my experience, a pretty accurate one. Then, how much weight are you trying to lose? A 20% cut from TDEE May not be appropriate for the amount of weight you have to lose. Besides, even if you go with your numbers and the 2719 number less 20% you should be eating the 2200 or so cals NOT the 1800 that you claimed in your first post was your MFP BMR.

    @heybales or @PAV8888 I’m tapping out to go to work, both of you have good insights into how the formulas and calculators work can one of you help clarify for this poster?
  • stanmann571
    stanmann571 Posts: 5,727 Member
    While it's possible that 1000 is too high, 0 is too low. You should be eating some part of those calories you've earned by activity.

    Without knowing what your calculator is showing you did for those calories it's difficult to say how many. But more than 0.
  • stanmann571
    stanmann571 Posts: 5,727 Member
    fuzacoza wrote: »
    My TDEE was calculated to include bodyfat:


    Total Daily Energy Expenditure,
    Based on your stats, the best estimate for your maintenance calories is 2,719 calories per day based on the Katch-McArdle Formula, which is widely known to be the most accurate when body fat is provided. The table below shows the difference if you were to have selected a different activity level.
    puzxyqfgaa2p.png


    Maintenance:
    gc55y2oqgx48.png

    If you're getting 1000 calorie adjustment, that's not moderate activity.
  • fuzacoza
    fuzacoza Posts: 33 Member
    fuzacoza wrote: »
    My TDEE was calculated to include bodyfat:


    Total Daily Energy Expenditure,
    Based on your stats, the best estimate for your maintenance calories is 2,719 calories per day based on the Katch-McArdle Formula, which is widely known to be the most accurate when body fat is provided. The table below shows the difference if you were to have selected a different activity level.
    puzxyqfgaa2p.png


    Maintenance:
    gc55y2oqgx48.png

    If you're getting 1000 calorie adjustment, that's not moderate activity.

    Think I am fairly fit and healthy, the exercise for that day, deffo not ATHLETE.

    ab3d684fxp5r.jpg




  • fuzacoza
    fuzacoza Posts: 33 Member
    edited June 2018
    WinoGelato wrote: »
    fuzacoza wrote: »
    To me eating exercise calories is like walking to McDonald's to buy a BigMac meal.

    Not properly fueling your activity by eating back at least some of those exercise calories could lead to loss of lean body mass, fatigue, and failure to get proper nutrition.

    You simply are conflating different approaches. If you don’t want to use MFP Numbers, you’re free to do that, many people follow a TDEE model and take their cut from that. However you are not doing that either - you are mixing the two with a misunderstanding of the basic numbers and approach.

    I get that, of course, you need energy to do anything and if you are doing things harder you need more energy. You need to eat proper food to begin with, low GI, complex carbs etc.
  • fuzacoza
    fuzacoza Posts: 33 Member
    RGv2 wrote: »
    fuzacoza wrote: »
    To me eating exercise calories is like walking to McDonald's to buy a BigMac meal.

    Then you don't understand how the tool "MFP" works.

    I think it's kind of distorted to compare properly fueling your body to that of walking to McDonalds for a BigMac. If I didn't eat back my calories, I'd come up with a net of 0-300 cals everyday. I don't see that as the most healthy.
    WinoGelato wrote: »
    No - this is basically all wrong. The number that MFP provides you is an estimate of your NEAT - which is your BMR (the cals you burn just being alive) plus an estimate of your calories from daily activity based on what activity level you chose. When you exercise and burn more calories than that you are meant to be eating those calories back to fuel your Total activity. FitBit provides a calorie adjustment which is representative of the difference between what MFP thought you’d burn and the total amount FitBit says you burn.

    Ignoring those completely means you are significantly under fueling your body, and thinking it’s good to try to be just at your BMR when you are clearly an active person? That’s just a recipe for failure.

    Eating 1800 ish calories and exercising off 1100 is the same as if you only ate 700 cals and did no exercise. Does that sound healthy?

    726576

    Yeah I can take good advice! I like food.
  • WinoGelato
    WinoGelato Posts: 13,454 Member
    fuzacoza wrote: »
    RGv2 wrote: »
    fuzacoza wrote: »
    To me eating exercise calories is like walking to McDonald's to buy a BigMac meal.

    Then you don't understand how the tool "MFP" works.

    I think it's kind of distorted to compare properly fueling your body to that of walking to McDonalds for a BigMac. If I didn't eat back my calories, I'd come up with a net of 0-300 cals everyday. I don't see that as the most healthy.
    WinoGelato wrote: »
    No - this is basically all wrong. The number that MFP provides you is an estimate of your NEAT - which is your BMR (the cals you burn just being alive) plus an estimate of your calories from daily activity based on what activity level you chose. When you exercise and burn more calories than that you are meant to be eating those calories back to fuel your Total activity. FitBit provides a calorie adjustment which is representative of the difference between what MFP thought you’d burn and the total amount FitBit says you burn.

    Ignoring those completely means you are significantly under fueling your body, and thinking it’s good to try to be just at your BMR when you are clearly an active person? That’s just a recipe for failure.

    Eating 1800 ish calories and exercising off 1100 is the same as if you only ate 700 cals and did no exercise. Does that sound healthy?

    726576

    Yeah I can take good advice! I like food.

    Well gosh I sure am glad you finally got some good advice.
  • fuzacoza
    fuzacoza Posts: 33 Member
    edited June 2018
    WinoGelato wrote: »
    fuzacoza wrote: »
    RGv2 wrote: »
    fuzacoza wrote: »
    To me eating exercise calories is like walking to McDonald's to buy a BigMac meal.

    Then you don't understand how the tool "MFP" works.

    I think it's kind of distorted to compare properly fueling your body to that of walking to McDonalds for a BigMac. If I didn't eat back my calories, I'd come up with a net of 0-300 cals everyday. I don't see that as the most healthy.
    WinoGelato wrote: »
    No - this is basically all wrong. The number that MFP provides you is an estimate of your NEAT - which is your BMR (the cals you burn just being alive) plus an estimate of your calories from daily activity based on what activity level you chose. When you exercise and burn more calories than that you are meant to be eating those calories back to fuel your Total activity. FitBit provides a calorie adjustment which is representative of the difference between what MFP thought you’d burn and the total amount FitBit says you burn.

    Ignoring those completely means you are significantly under fueling your body, and thinking it’s good to try to be just at your BMR when you are clearly an active person? That’s just a recipe for failure.

    Eating 1800 ish calories and exercising off 1100 is the same as if you only ate 700 cals and did no exercise. Does that sound healthy?

    726576

    Yeah I can take good advice! I like food.

    Well gosh I sure am glad you finally got some good advice.

    It is always welcome. I eat healthy and balanced I guess, so never felt the need to eat into my exercise cals. If I feel like it eat a banana or chai/whey shake pre and post runs. Never had health issues, I go for check ups, check my vitals etc. Posting here I realized I am in better shape I actually thought I was :p
  • stanmann571
    stanmann571 Posts: 5,727 Member
    fuzacoza wrote: »
    WinoGelato wrote: »
    fuzacoza wrote: »
    RGv2 wrote: »
    fuzacoza wrote: »
    To me eating exercise calories is like walking to McDonald's to buy a BigMac meal.

    Then you don't understand how the tool "MFP" works.

    I think it's kind of distorted to compare properly fueling your body to that of walking to McDonalds for a BigMac. If I didn't eat back my calories, I'd come up with a net of 0-300 cals everyday. I don't see that as the most healthy.
    WinoGelato wrote: »
    No - this is basically all wrong. The number that MFP provides you is an estimate of your NEAT - which is your BMR (the cals you burn just being alive) plus an estimate of your calories from daily activity based on what activity level you chose. When you exercise and burn more calories than that you are meant to be eating those calories back to fuel your Total activity. FitBit provides a calorie adjustment which is representative of the difference between what MFP thought you’d burn and the total amount FitBit says you burn.

    Ignoring those completely means you are significantly under fueling your body, and thinking it’s good to try to be just at your BMR when you are clearly an active person? That’s just a recipe for failure.

    Eating 1800 ish calories and exercising off 1100 is the same as if you only ate 700 cals and did no exercise. Does that sound healthy?

    726576

    Yeah I can take good advice! I like food.

    Well gosh I sure am glad you finally got some good advice.

    It is always welcome. I eat healthy and balanced I guess, so never felt the need to eat into my exercise cals. If I feel like it eat a banana or chai/whey shake pre and post runs. Never had health issues, I go for check ups, check my vitals etc. Posting here I realized I am in better shape I actually thought I was :p

    How many times a week do you run 10+ Kilometers?
  • fuzacoza
    fuzacoza Posts: 33 Member
    fuzacoza wrote: »
    WinoGelato wrote: »
    fuzacoza wrote: »
    RGv2 wrote: »
    fuzacoza wrote: »
    To me eating exercise calories is like walking to McDonald's to buy a BigMac meal.

    Then you don't understand how the tool "MFP" works.

    I think it's kind of distorted to compare properly fueling your body to that of walking to McDonalds for a BigMac. If I didn't eat back my calories, I'd come up with a net of 0-300 cals everyday. I don't see that as the most healthy.
    WinoGelato wrote: »
    No - this is basically all wrong. The number that MFP provides you is an estimate of your NEAT - which is your BMR (the cals you burn just being alive) plus an estimate of your calories from daily activity based on what activity level you chose. When you exercise and burn more calories than that you are meant to be eating those calories back to fuel your Total activity. FitBit provides a calorie adjustment which is representative of the difference between what MFP thought you’d burn and the total amount FitBit says you burn.

    Ignoring those completely means you are significantly under fueling your body, and thinking it’s good to try to be just at your BMR when you are clearly an active person? That’s just a recipe for failure.

    Eating 1800 ish calories and exercising off 1100 is the same as if you only ate 700 cals and did no exercise. Does that sound healthy?

    726576

    Yeah I can take good advice! I like food.

    Well gosh I sure am glad you finally got some good advice.

    It is always welcome. I eat healthy and balanced I guess, so never felt the need to eat into my exercise cals. If I feel like it eat a banana or chai/whey shake pre and post runs. Never had health issues, I go for check ups, check my vitals etc. Posting here I realized I am in better shape I actually thought I was :p

    How many times a week do you run 10+ Kilometers?

    I run every day at least 10k. Monday, Tuesday more pace at under 6', fat-burn zones Wed to Fri at over 7'/km, Parkrun Saturdays a 22 minute 5k. Maybe skip two days through any month.
  • PAV8888
    PAV8888 Posts: 14,252 Member
    @WinoGelato what's there to say?

    The guy KNOWS he is supposed to do a 20% cut from actual TDEE.

    He knows that his "MFP eating goal" PLUS "MFP selected deficit" PLUS "Fitbit adjustment" equals his Fitbit estimated TDEE for the day.

    Which means that with a selected deficit in the 500 to 1000 range that his TDEE is probably in the 3300 to 3800 (2900+chosen deficit)

    And be eats 1800.

    So he's just about doing a 50% deficit instead of 20% (or 25% while obese).

    Eventually he will crash. Neither the first one, nor the last....
  • stanmann571
    stanmann571 Posts: 5,727 Member
    fuzacoza wrote: »
    fuzacoza wrote: »
    WinoGelato wrote: »
    fuzacoza wrote: »
    RGv2 wrote: »
    fuzacoza wrote: »
    To me eating exercise calories is like walking to McDonald's to buy a BigMac meal.

    Then you don't understand how the tool "MFP" works.

    I think it's kind of distorted to compare properly fueling your body to that of walking to McDonalds for a BigMac. If I didn't eat back my calories, I'd come up with a net of 0-300 cals everyday. I don't see that as the most healthy.
    WinoGelato wrote: »
    No - this is basically all wrong. The number that MFP provides you is an estimate of your NEAT - which is your BMR (the cals you burn just being alive) plus an estimate of your calories from daily activity based on what activity level you chose. When you exercise and burn more calories than that you are meant to be eating those calories back to fuel your Total activity. FitBit provides a calorie adjustment which is representative of the difference between what MFP thought you’d burn and the total amount FitBit says you burn.

    Ignoring those completely means you are significantly under fueling your body, and thinking it’s good to try to be just at your BMR when you are clearly an active person? That’s just a recipe for failure.

    Eating 1800 ish calories and exercising off 1100 is the same as if you only ate 700 cals and did no exercise. Does that sound healthy?

    726576

    Yeah I can take good advice! I like food.

    Well gosh I sure am glad you finally got some good advice.

    It is always welcome. I eat healthy and balanced I guess, so never felt the need to eat into my exercise cals. If I feel like it eat a banana or chai/whey shake pre and post runs. Never had health issues, I go for check ups, check my vitals etc. Posting here I realized I am in better shape I actually thought I was :p

    How many times a week do you run 10+ Kilometers?

    I run every day at least 10k. Monday, Tuesday more pace at under 6', fat-burn zones Wed to Fri at over 7'/km, Parkrun Saturdays a 22 minute 5k. Maybe skip two days through any month.

    22 minute 5K every week.

    Seriously that's pretty awesome. That's fast enough to podium in some areas. Not a first place, there's always somebody.

    You really need to be feeding those runs. Carefully, no doubt, And congrats on losing 30Kg.
  • fuzacoza
    fuzacoza Posts: 33 Member
    PAV8888 wrote: »
    @WinoGelato what's there to say?

    The guy KNOWS he is supposed to do a 20% cut from actual TDEE.

    He knows that his "MFP eating goal" PLUS "MFP selected deficit" PLUS "Fitbit adjustment" equals his Fitbit estimated TDEE for the day.

    Which means that with a selected deficit in the 500 to 1000 range that his TDEE is probably in the 3300 to 3800 (2900+chosen deficit)

    And be eats 1800.

    So he's just about doing a 50% deficit instead of 20% (or 25% while obese).

    Eventually he will crash. Neither the first one, nor the last....

    Hey advise taken. Been doing this for a few years and I eat more some days, others less. Did a new calculation here
    punching in Athlete.

    https://tdeecalculator.net/result.php?s=metric&g=male&age=47&kg=89&cm=180&act=1.55&bf=28&f=1>

    ue5sev1phdny.png


    jxds6sc7ydp5.png

    I am hardly skinny with a 28% bodyfat, weighing 89kg and 180cm tall.
  • fuzacoza
    fuzacoza Posts: 33 Member
    edited June 2018
    fuzacoza wrote: »
    fuzacoza wrote: »
    WinoGelato wrote: »
    fuzacoza wrote: »
    RGv2 wrote: »
    fuzacoza wrote: »
    To me eating exercise calories is like walking to McDonald's to buy a BigMac meal.

    Then you don't understand how the tool "MFP" works.

    I think it's kind of distorted to compare properly fueling your body to that of walking to McDonalds for a BigMac. If I didn't eat back my calories, I'd come up with a net of 0-300 cals everyday. I don't see that as the most healthy.
    WinoGelato wrote: »
    No - this is basically all wrong. The number that MFP provides you is an estimate of your NEAT - which is your BMR (the cals you burn just being alive) plus an estimate of your calories from daily activity based on what activity level you chose. When you exercise and burn more calories than that you are meant to be eating those calories back to fuel your Total activity. FitBit provides a calorie adjustment which is representative of the difference between what MFP thought you’d burn and the total amount FitBit says you burn.

    Ignoring those completely means you are significantly under fueling your body, and thinking it’s good to try to be just at your BMR when you are clearly an active person? That’s just a recipe for failure.

    Eating 1800 ish calories and exercising off 1100 is the same as if you only ate 700 cals and did no exercise. Does that sound healthy?

    726576

    Yeah I can take good advice! I like food.

    Well gosh I sure am glad you finally got some good advice.

    It is always welcome. I eat healthy and balanced I guess, so never felt the need to eat into my exercise cals. If I feel like it eat a banana or chai/whey shake pre and post runs. Never had health issues, I go for check ups, check my vitals etc. Posting here I realized I am in better shape I actually thought I was :p

    How many times a week do you run 10+ Kilometers?

    I run every day at least 10k. Monday, Tuesday more pace at under 6', fat-burn zones Wed to Fri at over 7'/km, Parkrun Saturdays a 22 minute 5k. Maybe skip two days through any month.

    22 minute 5K every week.

    Seriously that's pretty awesome. That's fast enough to podium in some areas. Not a first place, there's always somebody.

    You really need to be feeding those runs. Carefully, no doubt, And congrats on losing 30Kg.

    Youngsters at the local track clock it in 15m now THAT is impressive. I normally end up in the top 10 in my age group, did well over 50 PRs. I just don't eat crap, and I can only eat THAT much healthy food.
  • erickirb
    erickirb Posts: 12,294 Member
    edited June 2018
    fuzacoza wrote: »
    PAV8888 wrote: »
    @WinoGelato what's there to say?

    The guy KNOWS he is supposed to do a 20% cut from actual TDEE.

    He knows that his "MFP eating goal" PLUS "MFP selected deficit" PLUS "Fitbit adjustment" equals his Fitbit estimated TDEE for the day.

    Which means that with a selected deficit in the 500 to 1000 range that his TDEE is probably in the 3300 to 3800 (2900+chosen deficit)

    And be eats 1800.

    So he's just about doing a 50% deficit instead of 20% (or 25% while obese).

    Eventually he will crash. Neither the first one, nor the last....

    Hey advise taken. Been doing this for a few years and I eat more some days, others less. Did a new calculation here
    punching in Athlete.

    https://tdeecalculator.net/result.php?s=metric&g=male&age=47&kg=89&cm=180&act=1.55&bf=28&f=1>

    ue5sev1phdny.png


    jxds6sc7ydp5.png

    I am hardly skinny with a 28% bodyfat, weighing 89kg and 180cm tall.

    You can really do a 22 minute 5K at that weight and amount of BF???
    At my fastest I was runing 21 minute 5ks at 9-10% BF% at 140 lbs.

    Also, no need for that much protein. 0.8-1 gram per lb of lean body mass is adequate, so for you that would be 113-141 grams per day. Based on weight and BF%
  • fuzacoza
    fuzacoza Posts: 33 Member
    edited June 2018
    erickirb wrote: »
    fuzacoza wrote: »
    PAV8888 wrote: »
    @WinoGelato what's there to say?

    The guy KNOWS he is supposed to do a 20% cut from actual TDEE.

    He knows that his "MFP eating goal" PLUS "MFP selected deficit" PLUS "Fitbit adjustment" equals his Fitbit estimated TDEE for the day.

    Which means that with a selected deficit in the 500 to 1000 range that his TDEE is probably in the 3300 to 3800 (2900+chosen deficit)

    And be eats 1800.

    So he's just about doing a 50% deficit instead of 20% (or 25% while obese).

    Eventually he will crash. Neither the first one, nor the last....

    Hey advise taken. Been doing this for a few years and I eat more some days, others less. Did a new calculation here
    punching in Athlete.

    https://tdeecalculator.net/result.php?s=metric&g=male&age=47&kg=89&cm=180&act=1.55&bf=28&f=1>

    ue5sev1phdny.png


    jxds6sc7ydp5.png

    I am hardly skinny with a 28% bodyfat, weighing 89kg and 180cm tall.

    You can really do a 22 minute 5K at that weight and amount of BF???
    At my fastest I was runing 21 minute 5ks at 9-10% BF% at 140 lbs.

    Also, no need for that much protein. 0.8-1 gram per lb of lean body mass is adequate, so for you that would be 113-141 grams per day. Based on weight and BF%

    Using one of those scales but yes that is what it says, according to that I am "obese". Guess my stats are weird, my resting HR drops below 40, I average 167BMP at a parkrun going at 4'39''/KM
  • stanmann571
    stanmann571 Posts: 5,727 Member
    fuzacoza wrote: »
    PAV8888 wrote: »
    @WinoGelato what's there to say?

    The guy KNOWS he is supposed to do a 20% cut from actual TDEE.

    He knows that his "MFP eating goal" PLUS "MFP selected deficit" PLUS "Fitbit adjustment" equals his Fitbit estimated TDEE for the day.

    Which means that with a selected deficit in the 500 to 1000 range that his TDEE is probably in the 3300 to 3800 (2900+chosen deficit)

    And be eats 1800.

    So he's just about doing a 50% deficit instead of 20% (or 25% while obese).

    Eventually he will crash. Neither the first one, nor the last....

    Hey advise taken. Been doing this for a few years and I eat more some days, others less. Did a new calculation here
    punching in Athlete.
    Good on you for being responsive and receptive.

    NO doubt there will be a few more knee jerk responses. Don't take them personally.
  • fuzacoza
    fuzacoza Posts: 33 Member
    fuzacoza wrote: »
    PAV8888 wrote: »
    @WinoGelato what's there to say?

    The guy KNOWS he is supposed to do a 20% cut from actual TDEE.

    He knows that his "MFP eating goal" PLUS "MFP selected deficit" PLUS "Fitbit adjustment" equals his Fitbit estimated TDEE for the day.

    Which means that with a selected deficit in the 500 to 1000 range that his TDEE is probably in the 3300 to 3800 (2900+chosen deficit)

    And be eats 1800.

    So he's just about doing a 50% deficit instead of 20% (or 25% while obese).

    Eventually he will crash. Neither the first one, nor the last....

    Hey advise taken. Been doing this for a few years and I eat more some days, others less. Did a new calculation here
    punching in Athlete.
    Good on you for being responsive and receptive.

    NO doubt there will be a few more knee jerk responses. Don't take them personally.

    No doubt, if you ever been on Planet Rugby's Forum you can take it on the chin!
  • collectingblues
    collectingblues Posts: 2,541 Member
    PAV8888 wrote: »
    @WinoGelato what's there to say?

    The guy KNOWS he is supposed to do a 20% cut from actual TDEE.

    He knows that his "MFP eating goal" PLUS "MFP selected deficit" PLUS "Fitbit adjustment" equals his Fitbit estimated TDEE for the day.

    Which means that with a selected deficit in the 500 to 1000 range that his TDEE is probably in the 3300 to 3800 (2900+chosen deficit)

    And be eats 1800.

    So he's just about doing a 50% deficit instead of 20% (or 25% while obese).

    Eventually he will crash. Neither the first one, nor the last....

    Eating proper levels of calories are *totally* overrated, you know. ;)