The math of weight loss

WillPowerYes
WillPowerYes Posts: 103 Member
edited December 22 in Health and Weight Loss
This thread concerns the math of weight loss: how does the computation of calories work in weight loss (or gain)?

To loose a pound, you need 3500 less calories than what it takes to maintain your present weight. These calories can be saved by eating less, or spent by exercising.

I currently need approximately 1600 calories a day to maintain my current weight, with consideration to my activity level. [Google “How many calories to maintain weight” to find a tool. I used http://www.caloriecontrol.org/ ]

MFP recommends my daily calorie intake at 1200.

Doing the math:
1600 calories [maintenance] minus 1200 [daily goal] equals 400 less calories per day.
3500 [one pound] divided by 400 [calories per day] equals nearly 9 days to loose a pound.

What??? 9 days for a pound? Is my math wrong?

[Yes, I know that I can exercise more, or eat less, to speed up the process. But this is an “understanding how does it works” question, that is, about the math of weight loss.]

Replies

  • Pebble321
    Pebble321 Posts: 6,423 Member
    Your maths sounds right - but your mainteance calories sound very low.
    If you only need to eat 1600 to maintain you must already be quite light, so losing 1 pound in 9 days seems very reasonable to me.
  • Pfeiffer24
    Pfeiffer24 Posts: 106 Member
    Interesting :)
  • MoreBean13
    MoreBean13 Posts: 8,701 Member
    1600 sounds wrong for your maintenance calories. Too low. Sounds like that is your BMR, and you need to apply an activity multiplier to get to your TDEE- a.k.a. the number of calories you need to maintain your weight. For a sedentary person, an activity multiplier of 1.2 would be applied, giving you a TDEE of 1920 for a BMR of 1600. Most people aren't truly sedentary, though.
  • WillPowerYes
    WillPowerYes Posts: 103 Member
    Morebean13, please which tool are you using so I can check it out, thanks.

    I used sedentary/low activity for both the weight maintenance tool, and also for the MFP tool, for uniformity. I'm the type to be conservative in my calculations, that is, I don't overestimate my exercise ~ and neither do I omit the small calories from my food chart.

    Anyone else give my math question (tools) a try with their own numbers?
  • MoreBean13
    MoreBean13 Posts: 8,701 Member
    I use the tools at Fat2FitRadio.com - I realized after I wrote that post that your BMR might be lower than I am used to seeing b/c you are a bit older- age does reduce your BMR. It's good to be conservative, but many people shoot themselves in the foot by being too conservative when they're doing these calculations, and end up with an unsustainably large deficit.

    Your math looks fine, btw, if all your inputs are right.
  • mcarter99
    mcarter99 Posts: 1,666 Member
    Your math is right if your inputs are correct. If you're not very overweight or tall or active, they could be. My (TDEE) estimate at my goal weight is under 1700, and I'm not particularly short and that weight isn't particularly low. At my current weight, 30 lbs. over goal, my TDEE is under 1800 unless I add exercise.
  • WillPowerYes
    WillPowerYes Posts: 103 Member
    Thanks Morebean13. Using your link, I get:
    Sedentary (little or no exercise, desk job) 1510
    Lightly Active (light exercise/sports 1-3 days/wk) 1730

    So, I think 1600 is probably about right for a medium number.

    Dang .....I''ll not be able to look at 1200 calories without thinking "that's gonna' take over a week for one pound dearie".
  • Sabine_Stroehm
    Sabine_Stroehm Posts: 19,263 Member
    1600:based on...how old are you, how tall are you ( a personal pet peeve of mine that mfp folks rarely say how tall they are) what your gender is, how much you currently weigh, how active you are AND>>>>>>>>>>>>>>>>>> are you currently taking any prescribed medications that can lead to or prevent weight loss>>>>>>>>>>>>>>>AND??>>>>>>>>>>>>>>>>>>> are you currently a woman in menopause?>>>>>>>>>>>>>>>>>>>and are you breast feeding and ???????????ANNNNND>>>>


    my point: there are a lot of variables. You seem to be at the beginning of this journey, and congrats for that! BE ready for folks to have divergent experiences from what you're expecting and/or experiencing yourself.
  • WillPowerYes
    WillPowerYes Posts: 103 Member
    The tools ask age, height, current weight, activity, M/F, etc in their calculations. Not meds, but I don't have any of those that affect weight.

    It is just an "arrrggggh" moment of realization for me. My instincts to avoid math in school were right. Ha.
  • bikinibeliever
    bikinibeliever Posts: 832 Member
    bumping to lead someone else here.
  • 12by311
    12by311 Posts: 1,716 Member
    If you have less to lose, yes, it takes longer.
  • WillPowerYes
    WillPowerYes Posts: 103 Member
    For me, and perhaps others, loosing the first five pounds is the "easiest". Today, at the 2 week mark, I've lost 5 pounds. That comes to a tiny bit over 2 pounds a week. But I've worked hard on watching my calories, and do not consume the full recommended [for me] 1200 calories per day. I'm sort of apprehensive about the upcoming weekly increments, because I think that progress will be slower (now that the easier first five is done). My apprehension is actually impatience, I guess. Even if I can keep up at a 2 pound loss per week (which I know won't be happening as I get less weight to loose), that is the end of summer before I've lost my wanted 20 lbs. Yep, impatience is my problem right now.
  • imissbagels
    imissbagels Posts: 166 Member
    bump
  • ElizabethRoad
    ElizabethRoad Posts: 5,138 Member
    Why do you all think no one could be at 1600 for maintenance?
  • WillPowerYes
    WillPowerYes Posts: 103 Member
    Hi ElizabethRoad. We finally settled on 1600 being accurate for some people (like me after plugging in my personal details). I think the previous comments about the "low number" of 1600 reflects on what I was posting about, that the MATH of weight loss is surprising when you look at the numbers.

    Goodness, I guess I should enjoy 1600 while I have it, as it will even lower as I get even less weight to maintain.
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