Help me understand the "in 5 weeks you'd weigh _____"

americanfatass
americanfatass Posts: 2
in Getting Started
HI all. I used MFP successfully a couple years ago to lose 35 pounds, mostly through diet. A year later, I abandoned the MFP / diet approach and started doing traithlons and half-=marathons, but never lost another pound. After I burned out and got injured, I took a 6 month break--- gained some of the wieght back. So-- here I am again. This time I'm gonna do diet AND exercise.

My question for you: After you complete each days' logging it says "if every day were like today you'd weigh (example) 180 pounds in 5 weeks".

5 weeks has come and gone a lot of times, with consistent eating and exercise patterns. it just doesnt seem to ever get there.

I'm pretty diligent about logging *everything* and am realistic and honest about portions and such.

Advice ? Is this just a BS false encouragement to help me sleep (that) night ?

Replies

  • cwolfman13
    cwolfman13 Posts: 41,865 Member
    For me it was always pretty accurate give or take, not exact. It's just a projection. Also, every day has to be pretty much like that day for it to be accurate. I don't know...when I was set to lose 1.5 Lbs per week, I pretty much lost 1.5 Lbs per week...when it was 1 Lb per week I pretty much lost 1 Lb per week...it wasn't completely linear but by the time 5 weeks rolled around, yeah...I found it pretty accurate.

    The biggest thing is consistency...I always hit my goals and I weighed out anything that could possibly be weighed out and was as precise as possible. If I couldn't weigh it I measured it...I rarely eyeballed a portion of anything. With calorie counting, precision is pretty key...500 calories per day deficit to lose 1 Lb per week really isn't as much room for error as it would appear.

    I would add that once I hit a healthy BF%, things didn't really seem to move at the projected rate...but I kind of expected that.
  • tilmoph
    tilmoph Posts: 72 Member
    It's a straight calc based on the activity level you set and the exercise you log. If you set activity too high or your metabolism just runs a bit slower than average, the calc won't know that and be off. It's pretty accurate for me, so I'm fairly certain it's not just too make people feel better (they'd just feel worse when they missed the mark afterall)
  • BusyRaeNOTBusty
    BusyRaeNOTBusty Posts: 7,166 Member
    It's just simple math. Based on your weight, age and activity level MFP guesses your TDEE (without exercise). It then multiples that TDEE by 7 and by 5 (5 weeks), then calculates how much of a total deficit you'd have in 5 weeks based on the exact calories you ate today. It divides that by 3500 calories for a pound.

    Estimated TDEE: 2000

    Burned in 5 weeks: 2000 * 5 * 7 = 70,000

    Lets say you ate 1800 today.

    1800 * 5 * 7 = 63,000

    70,000 - 63,000 = 7,000

    7,000 / 3500 = 2 lbs.

    If you weight 182 today, you'd weight 180 in 5 weeks.


    But yeah, life isn't that simple. You don't eat exactly 1800 every day. You don't burn exactly 2000 every day (you might never burn that much, it's just a guess). You don't lose only fat, you lose and gain water, you lose muscle, etc.
  • BusyRaeNOTBusty
    BusyRaeNOTBusty Posts: 7,166 Member
    Also, read this:

    http://impruvism.com/slow-fat-loss/
  • Nissi51
    Nissi51 Posts: 381 Member
    That message makes me crazy! lol
  • tigersword
    tigersword Posts: 8,059 Member
    It's purely based on that one day. Hence "If every day were like today..." If you have a 1000 calorie deficit for that one day, it calculates what your weight would be 5 weeks out if you had exactly a 1000 calorie deficit every day for the next 5 weeks. If you have a 400 calorie deficit the next day, it will calculate what your weight would be if you had exactly a 400 calorie deficit every day for the next 5 weeks.

    It's pretty much a useless number, although it can show you potentially how consistent you are.
  • Unknown
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  • Mr_Knight
    Mr_Knight Posts: 9,532 Member
    It's just simple math. Based on your weight, age and activity level MFP guesses your TDEE (without exercise).

    Does it use your actual, logged exercise to set your "activity level"?
  • jonswife0206
    jonswife0206 Posts: 125 Member
    It's the evil carrot hanging at the end of the stick. I don't even click that button anymore just for sanity sake.
  • MB_Positif
    MB_Positif Posts: 8,897 Member
    I never paid attention to it.
  • toni5363
    toni5363 Posts: 55 Member
    I often thought about how that system come up with what you would weigh in 5 weeks if your caloric intake was whatever it was for that that; everyday. Reading your comments helped my to understand it more. Thanks!
  • DebbieLyn63
    DebbieLyn63 Posts: 2,654 Member
    Advice ? Is this just a BS false encouragement to help me sleep (that) night ?

    Yep, pretty much this for most of us. The problem is that MFP uses a calculator to figure your BMR by your height, weight, and age. Doesn't take into account body composition, hormonal issues, or genetics. The exercise database is also overinflated for most people. To get my true BMR on here, I had to take 9 inches off of my height!
  • americanfatass
    americanfatass Posts: 2
    thanks for the replies, sounds like it's (perhaps overly) a generalization based on one snapshot in time. I get it. Thanks for the math too

    :-)

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