Does anyone have a formula to project weight loss?

MegaMooseEsq
MegaMooseEsq Posts: 3,118 Member
edited August 2017 in Health and Weight Loss
MFP appeals to me because I'm a numbers nut, but unfortunately, I'm only a talented novice when it comes to spreadsheets. I've been trying to create a formula to predict my weight loss going forward, and I thought I had it about right, but when I applied it to my last seven months of tracking it was a little *too* accurate, which makes me think I'm goofing up somewhere. Can any numbers nuts help me out?

Here's what I came up with: (-[yesterday's weight]*13+[today's net calories])/3500+[yesterday's weight]

I'm estimating TDEE using the formula found here: http://www.bodyrecomposition.com/fat-loss/how-to-estimate-maintenance-caloric-intake.html/. I've used the low estimate for women to get 13 kcal/lb.

ETA: Oof, apparently I came across way more woo than intended - I suppose it is Friday. I am definitely not trying to predict what the scale will say tomorrow - I've been losing for several months now and I know how this works. However, because I set different calorie goals for different days of the week, I have a hard time with online projectors such as the one MFP uses when you close out your diary. I'm trying to reverse-engineer that formula for goal-setting purposes and to save myself having to type in my stats over and over. Thanks!
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Replies

  • tcunbeliever
    tcunbeliever Posts: 8,219 Member
    How can it be too accurate? I don't understand...if it's accurate then it's working, right???
  • rybo
    rybo Posts: 5,424 Member
    It's pretty much impossible to calculate.
  • CoachJen71
    CoachJen71 Posts: 1,200 Member
    Weight loss looks like uneven steps on a graph, not a smooth downward line. The body lets go of weight, but not in an orderly and predictable fashion.
  • MegaMooseEsq
    MegaMooseEsq Posts: 3,118 Member
    I know that there are lots of variables and it won't be at all perfect - I'm just looking for estimated trend lines to help set my weekly and monthly goals. Like MFP uses when you close out your food diary. Plus I figure if I can figure out the "ideal" formula, I can use it to backtrack and see what my actual numbers were. Then I've got all sorts of data to play with.
  • MegaMooseEsq
    MegaMooseEsq Posts: 3,118 Member

    Yes, this is exactly what I'm trying to reverse engineer. It's got to be possible, right?
  • ISweat4This
    ISweat4This Posts: 653 Member
    edited August 2017
    I was hoping it would download to an excel file with formulas but no luck, but it is possible.

  • MegaMooseEsq
    MegaMooseEsq Posts: 3,118 Member
    How can it be too accurate? I don't understand...if it's accurate then it's working, right???

    My concern is that I would not expect a predicted weight loss to track all that closely with an actual weight loss. The formula is taking one (mostly) objective number - the reading on my scale - estimating my TDEE off of a rough formula, then using my estimated monthly calories (in this case, the calories I logged over the first half of the year, and we all know how precise logging can be), and the estimated calories it takes to burn off a pound, and predicting my weight a month (or day) later. I would not expect those numbers to line up all that closely, since that would seem to say that all of those estimates were pretty much spot on. Or maybe that is just how it works when you look at trends and I'm just overthinking this?
  • lorrpb
    lorrpb Posts: 11,463 Member
    Why not use a trending app like Libra or Happy Scale?
  • mebelfanti
    mebelfanti Posts: 326 Member
    edited August 2017
    I have a spreadsheet where I log my weight every week, calculate the average pounds lost per week (starting from when I first started keeping track a few months ago), then use that average to predict my weight for each week for the rest of the year. Would that help?
  • jemhh
    jemhh Posts: 14,261 Member
    How can it be too accurate? I don't understand...if it's accurate then it's working, right???

    My concern is that I would not expect a predicted weight loss to track all that closely with an actual weight loss. The formula is taking one (mostly) objective number - the reading on my scale - estimating my TDEE off of a rough formula, then using my estimated monthly calories (in this case, the calories I logged over the first half of the year, and we all know how precise logging can be), and the estimated calories it takes to burn off a pound, and predicting my weight a month (or day) later. I would not expect those numbers to line up all that closely, since that would seem to say that all of those estimates were pretty much spot on. Or maybe that is just how it works when you look at trends and I'm just overthinking this?

    I still don't know what you are going for here. It sounds like you want to predict your weight loss specifically because you know that the prediction will not align with reality.
  • Philtex
    Philtex Posts: 1,133 Member
    If I Lost One Pound per Week

    By Valentine's Day, I'd be 7 pounds lighter.
    I'm loving it!

    By St. Patrick's Day, I'd be 11 pounds lighter.
    With the luck of the Irish, I'll make my goal!

    By Easter, I'd be 16 pounds lighter.
    I'd be a cute bunny!

    By Memorial Day, I'd be 23 pounds lighter!
    Won't let it rain on my parade!

    By Flag Day, I'd be 25 pounds lighter.
    Boy, could I wave my flag, then!

    By Independence Day, I'd be 27 pounds lighter.
    That's a great independence from over eating!

    By Labor Day, I'd be 36 pounds lighter.
    What a wonderful reward for my hard work!

    By Columbus Day, I'd be 41 pounds lighter.
    What a joy to discover what I can do!

    By Halloween, I'd be 44 pounds lighter.
    I didn't think I had a ghost of a chance!

    By Thanksgiving, I'd be 47 pounds lighter.
    I have so much to be thankful for!

    By Christmas Eve, I'd be 51 pounds lighter.
    Talk about being merry!

    By New Year's Eve, I'd be 52 pounds lighter.
    It's not just a new year, it's a new ME!
  • AnnPT77
    AnnPT77 Posts: 33,810 Member
    I don't have links at have links at hand, but over time there have been pretty sophisticated spreadsheets developed to estimate TDEE from your MFP data, with links in forum posts. That'd be a better start - way better than the TDEE calculators if you vary much from the norm.

    Maybe someone else has the links, or you can find them by forum search. I'm sorry I don't have them - they're on a device that's bricked right now.

    Of course, using something like this depends on accurate logging of food, exercise and scale weight over quite a period of time. But if you're a data geek, you probably have that.

    Libra gave me decent projections most of the time when I was in a consistent deficit. Now, in maintenance, I get more of a "rolling hills" effect. You can see a sample snip in the ticker in my MFP profile page - at the left, a small piece of the sort of smooth descent to goal, then the mini-hills start. ;)
  • MegaMooseEsq
    MegaMooseEsq Posts: 3,118 Member
    edited August 2017
    AnnPT77 wrote: »
    I don't have links at have links at hand, but over time there have been pretty sophisticated spreadsheets developed to estimate TDEE from your MFP data, with links in forum posts. That'd be a better start - way better than the TDEE calculators if you vary much from the norm.

    Maybe someone else has the links, or you can find them by forum search. I'm sorry I don't have them - they're on a device that's bricked right now.

    Of course, using something like this depends on accurate logging of food, exercise and scale weight over quite a period of time. But if you're a data geek, you probably have that.

    Libra gave me decent projections most of the time when I was in a consistent deficit. Now, in maintenance, I get more of a "rolling hills" effect. You can see a sample snip in the ticker in my MFP profile page - at the left, a small piece of the sort of smooth descent to goal, then the mini-hills start. ;)

    That's exactly the kind of thing I'm looking for! I tried to search the forum archives earlier but got distracted - I'll keep looking, or maybe someone will pop up who remembers a link.

    jemhh wrote: »
    How can it be too accurate? I don't understand...if it's accurate then it's working, right???

    My concern is that I would not expect a predicted weight loss to track all that closely with an actual weight loss. The formula is taking one (mostly) objective number - the reading on my scale - estimating my TDEE off of a rough formula, then using my estimated monthly calories (in this case, the calories I logged over the first half of the year, and we all know how precise logging can be), and the estimated calories it takes to burn off a pound, and predicting my weight a month (or day) later. I would not expect those numbers to line up all that closely, since that would seem to say that all of those estimates were pretty much spot on. Or maybe that is just how it works when you look at trends and I'm just overthinking this?

    I still don't know what you are going for here. It sounds like you want to predict your weight loss specifically because you know that the prediction will not align with reality.

    Well, sort of - what I'm trying to do is identify, based on my past data, where (if anywhere) I'm going wrong with my logging based on how my numbers deviate from a predictable formula.

    lorrpb wrote: »
    Why not use a trending app like Libra or Happy Scale?

    Mostly I want to figure out how to do it to see if I can, but I'm also hoping to use the formula to play with my data outside of the restrictions of an app.

    mebelfanti wrote: »
    I have a spreadsheet where I log my weight every week, calculate the average pounds lost per week (starting from when I first started keeping track a few months ago), then use that average to predict my weight for each week for the rest of the year. Would that help?

    That would probably work just fine - weirdly I didn't think of that since I was so preoccupied with trying to work out the standard formula. I'd have to tweak it to figure out the effect of future calorie changes, but I think I know how to do that. Thanks!
  • AnnPT77
    AnnPT77 Posts: 33,810 Member
    edited August 2017
    Try this:

    http://community.myfitnesspal.com/en/discussion/813720

    I have no idea whether the spreadsheet is compatible with current MFP, but it still exists and may be a source for ideas, at least.
  • MegaMooseEsq
    MegaMooseEsq Posts: 3,118 Member
    AnnPT77 wrote: »
    Try this:

    http://community.myfitnesspal.com/en/discussion/813720

    I have no idea whether the spreadsheet is compatible with current MFP, but it still exists and may be a source for ideas, at least.

    Oooooh, thank you! So many ideas!
  • VeronicaA76
    VeronicaA76 Posts: 1,116 Member
    edited August 2017
    How good are you at calculous? The formula is a bit daunting. As your daily weight changes via CICO, this is a double variable equation. One is weight, the other is calorie deficit per day based on a recalculation of daily weight changes. You're maintenance calories are the start, and you need to use the Harris-benedict equation as part of your equation.
  • Arkie_Ali
    Arkie_Ali Posts: 106 Member
    I use an excel spreadsheet with a column of weigh-in dates (each Friday), a column of actual weight on that day, and a column of estimated weight (expectation of 1 lb loss a week). I use those columns to create a line graph in the spreadsheet with a trending line. The expected weight line vs. the trending line just shows me how I'm trending compared to how I had estimated. The actual weight line just gives me a nice visual of my progress. I like this because I can also see exactly where TOM has affected weight fluctuations. Would something like that work for you? This won't really predict future weight though.
  • robm1brown
    robm1brown Posts: 71 Member
    Show the calculus. Please. Pretty please.