Struggling to understand my weekly weight loss amounts

KJK1LL3R
KJK1LL3R Posts: 6
in Health and Weight Loss
Hey guys,

For the past 3 weeks I've been using the Ki-Fit (Bodymedia FIT Advantage) armband in conjunction with logging my foods here on MFP with a goal to lose 2lbs per week. At the end of every day I log my deficit for that day on an excel spread sheet and after 7 days I total each days deficit for a total overall weekly deficit figure. I then divide this figure by 3500 to give me an idea of how many pounds I should have lost.

So for the 1st week, I worked out that I should have lost 2lbs and I ended up losing 2.1lbs for the week so I felt it was pretty accurate.
Then in the 2nd week, my figures were predicting that I would lose 1.5lbs but I actually lost 2.7lbs, a big difference.
Then in this 3rd week, my figures were predicting that I would lose 1.7lbs but I only lost 0.4lbs.

I can't really make sense of these fluctuations. The whole reason I'm logging my food and using the Bodymedia armband is so that I can fairly accurately calculate my deficit and control how much I lose each week.

In terms of my calories, I'm not doing any training but every day I burn 2500-3500 per day depending on how busy my day is at work. Each day I eat approximately 2000 calories and my average weekly macros are 55% carbs, 25% protein & 20% fat. According to the IIFYM online calculator, my BMR is in the 1700-1800 range so I always eat above that in order to avoid "starvation mode" so I don't think that could be the issue.

I really can't make sense of it, and I'd appreciate any advice?

Thanks!

Replies

  • MinnieInMaine
    MinnieInMaine Posts: 6,400 Member
    Weight loss is not linear. You have to go with the averages.

    Between your three weeks, you've lost a total of 5.2 pounds which is exactly on target with your armband's predictions, the timing was just off a bit (2.1+2.7+0.4 = 5.2).

    You're on track, don't worry about it.
  • spaingirl2011
    spaingirl2011 Posts: 763 Member
    My advice is to let it go and just keep doing what you're doing--because you're obviously doing something right. Your body does not care what a calculator says and will not always lose on cue. Some weeks I lose a lot, some weeks I lose a little, and some weeks I don't lose anything at all. You may find that you have a good loss next week. Keep in mind that your losses may slow down after the first couple of weeks or so (since the firs couple of weeks people tend to lose water weight as well as fat). Just keep chugging along and look for overall trends instead of getting hung up on one week!

    Best of luck to you!
  • cwolfman13
    cwolfman13 Posts: 41,865 Member
    Weight loss isn't a linear function...it's a general trend over time. You're going to have weeks with bigger losses than expected...weeks with smaller losses...weeks with no losses...weeks with small gains, etc. But over the course of time, if you're accurate in your intake and burn it will average out.

    Again, it's just not linear the way you're thinking it is.
  • KJK1LL3R
    KJK1LL3R Posts: 6
    Thanks for the responses.
    I was under the assumption that if I had a weekly deficit of 3500, I would lose exactly 1lb every single week provided that I was eating above my BMR.
    I'm a little frustrated that this is not the case as I was hoping I could meticulously control exactly how much weight I lost each week.
  • KJK1LL3R
    KJK1LL3R Posts: 6
    Would I be better off weighing myself every 4 weeks instead of on a weekly basis?
    That way I can see if my average is still close to the 2lbs per week even if I didn't actually lose 2lbs each week?
  • BL_Coleman
    BL_Coleman Posts: 324 Member
    If you are going to micro-manage and freak out if you are not on "target" I would go to weighing every other week or 4 weeks. I have found that my weight loss is consistent over a month, but not week to week. Body types vary and so do reactions. You are doing great, just keep it up and try not to over analyze...i know its hard
  • KJK1LL3R
    KJK1LL3R Posts: 6
    Ok so I get what you guys are saying, that I should look at my average weekly loss over a period of time.
    But this week, my stats based on my caloric deficit were predicting a 1.4lb loss but I actually gained 0.8lbs.
    I can't understand how I can gain so much when I've been in a deficit every day yet still consumed above my BMR to prevent "starvation mode" occurring. I don't do any exercise so putting it down to muscle gain can also probably be ruled out as an explanation for the gain.

    If looking at it over a period of 4 weeks, my calorie deficit stats predicted a total loss of 6.6lbs but I've actually only lost 4.4lbs.
    So that means my weekly averages over the longer period still doesn't match up as my stats predicted an average loss of 1.6lbs per week but in reality I only averaged 1.1lbs per week so I'm off by half a pound per week.

    I could understand what you guys were saying about it not being linear and some weeks I'll lose a little and some weeks I'll lose a lot but I thought that there would always be a loss of some sort each week as opposed to a gain or at the very least I'd maintain the previous week's weight.

    The only thing I can possibly think of, is that perhaps I didn't drink as much water this past week as I would usually so I don't know if that makes much of a difference? Maybe I should start daily exercising to increase my daily deficits?
  • betreich
    betreich Posts: 51 Member
    maybe you should try and relax a bit, keep with the program and trust in your body that over time you will see the result you want, short term fluctuations can happen due to hormonal changes, if you have eaten something salty, or other reasons. Our bodies are complex living organisms, not computers, and I don't think that you can expect a totally predictable output number, or exercise that degree of control when there are so many variables at play in how our bodies work- but I wish you well on your weight loss journey.
  • Dewymorning
    Dewymorning Posts: 762 Member
    Thanks for the responses.
    I was under the assumption that if I had a weekly deficit of 3500, I would lose exactly 1lb every single week provided that I was eating above my BMR.
    I'm a little frustrated that this is not the case as I was hoping I could meticulously control exactly how much weight I lost each week.

    1 pound of fat has 3500 calories of energy.

    The idea is that is we create a deficit our body has to burn the fat to get the energy.

    That is not exactly how our body works, but the general principle still holds.

    According to the scale I gained a small amount this week, at first I felt discouraged, but then one of my lovely MFP friends reminded me that there was no way I had eaten enough to gain weight. And she is right, I ate the same amount as the past two weeks and I lost the last two weeks. My theory now is that the hot weather from the past few days has caused me to retain water (I live in the southern hemisphere).

    A lot of factors influence our weight. So because of this remember when you weigh in not to pay attention to the exact number but just to monitor and make sure you are heading in the right direction.
  • jennifer_417
    jennifer_417 Posts: 12,344 Member
    Thanks for the responses.
    I was under the assumption that if I had a weekly deficit of 3500, I would lose exactly 1lb every single week provided that I was eating above my BMR.
    I'm a little frustrated that this is not the case as I was hoping I could meticulously control exactly how much weight I lost each week.

    Yeah, definitely not how it works. Sorry.
  • FredSetToGetFit
    FredSetToGetFit Posts: 286 Member
    Weight loss is not linear. You have to go with the averages.

    Between your three weeks, you've lost a total of 5.2 pounds which is exactly on target with your armband's predictions, the timing was just off a bit (2.1+2.7+0.4 = 5.2).

    You're on track, don't worry about it.

    *this*
  • kiwitechgirl
    kiwitechgirl Posts: 145 Member
    Thanks for the responses.
    I was under the assumption that if I had a weekly deficit of 3500, I would lose exactly 1lb every single week provided that I was eating above my BMR.
    I'm a little frustrated that this is not the case as I was hoping I could meticulously control exactly how much weight I lost each week.

    You can't be 100% sure that your intake and burns are accurate down to the very last calorie - even if you're weighing your food exactly, there's still a margin of error in there. You also can't know exactly what your BMR is - you can estimate pretty closely, but it won't be exactly 100% all of the time. And, you may burn less or more day to day depending on activity - I know I have busy days at work when I'm on my feet the whole day, and quieter days where I spend much more time at my desk. All these come into play - you just can't guarantee an exact number as your deficit, it's always going to be an estimation.
  • MinnieInMaine
    MinnieInMaine Posts: 6,400 Member
    Ok so I get what you guys are saying, that I should look at my average weekly loss over a period of time.
    But this week, my stats based on my caloric deficit were predicting a 1.4lb loss but I actually gained 0.8lbs.
    I can't understand how I can gain so much when I've been in a deficit every day yet still consumed above my BMR to prevent "starvation mode" occurring. I don't do any exercise so putting it down to muscle gain can also probably be ruled out as an explanation for the gain.

    If looking at it over a period of 4 weeks, my calorie deficit stats predicted a total loss of 6.6lbs but I've actually only lost 4.4lbs.
    So that means my weekly averages over the longer period still doesn't match up as my stats predicted an average loss of 1.6lbs per week but in reality I only averaged 1.1lbs per week so I'm off by half a pound per week.

    I could understand what you guys were saying about it not being linear and some weeks I'll lose a little and some weeks I'll lose a lot but I thought that there would always be a loss of some sort each week as opposed to a gain or at the very least I'd maintain the previous week's weight.

    The only thing I can possibly think of, is that perhaps I didn't drink as much water this past week as I would usually so I don't know if that makes much of a difference? Maybe I should start daily exercising to increase my daily deficits?

    I don't think you do understand or you wouldn't be stressing so much of it. It's water weight. Calories are not the only factor in weight loss - maybe your sodium was a bit high and yeah, not drinking enough water will do it too. Maybe this is a trend for you - you didn't lose as much as you thought one week but the next week more than made up for it - or maybe it'll take a couple weeks to catch up. Give it time! You are trying to look at this too logically - the body is not a machine and most of these numbers are estimates (good ones at best, off several hundred calories at worst).

    Exercising might help but do it for good health, not for weight loss and make sure you eat back at least half of earned caloreis because you don't want TOO high of a deficit. Plus, you need to know that many times when you first start exercising, you may see a stall or gain due to water and glycogen retention (part of the natural healing process of microtears - completely normal).

    Seriously, you really just need to be patient and keep tracking and try to let it go.
  • deksgrl
    deksgrl Posts: 7,237 Member

    I can't really make sense of these fluctuations.

    Because there are many factors, many complex processes going on in your body. As long as the trend continues down, don't worry about it. If/when your loss comes to a stand still for several weeks, then reevaluate.

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