Good Results - need help with the math

NiagaraCheryl
NiagaraCheryl Posts: 56 Member
edited January 28 in Motivation and Support
I stepped on the scale today, and I see that my body fat is now at 30%! Whoo hoo! And to just ensure it wasn't a wacky cheap-o scale read out, I checked it against an online calculator, and the number there was even better at 26.92%. I was originally at 50%, so I think whatever is working.

However, I'm stumped on what exactly this means, so I'm hoping a math whiz can help me out.

Stats:
Height 5' 5"
Age 46

May 2012 June 2013
Weight 212 lbs 185 lbs
Body Fat 50% 30%

So, looking at my weight loss and the change in body fat percentage, the numbers suggest to me that I've not only lost fat but also gained muscle. Does this make sense? I've been working out 3 times a week with both weights and cardio. I've been keeping a calorie deficit while eating back my workout calories.

I've lost a total of 27 lbs so far and I still need to lose another 45. I'm happy with the loss but wonder if I should be farther along, although I will admit that it's been easy enough. I don't feel like I'm denying myself anything and that means a lot.


I appreciate your help!

Replies

  • jacksonpt
    jacksonpt Posts: 10,413 Member
    based on some quick math...

    ...........................May 2012.........June 2013
    weight...................212....................185
    bf %.......................50%...................30%
    fat mass.............106lbs...............55.5lbs
    lean mass..........160lbs...............129lbs


    Awesome work!
  • TwelveSticks
    TwelveSticks Posts: 288 Member
    No... it doesn't make sense.

    At 212, with 50% body fat, your fat and lean body masses would both have been 106 lb.

    At 185, with 30% body fat, your fat would weight 55.5 lbs and your lean body mass would be 129.5 lbs

    It is generally accepted that (no matter what we might like to believe), you can't gain any significant muscle while eating a calorie deficit, so I really don't think it is possible for your lean body mass to have gone up by 23.5 lbs.

    I suggest that at least one of your BF readings was wrong. How are you measuring them? The scales that tell you your BF are notoriously flaky (I find that it helps if you dampen your feet before you step on them) and should only be used as a rough guide at best.
  • jacksonpt
    jacksonpt Posts: 10,413 Member
    No... it doesn't make sense.

    At 212, with 50% body fat, your fat and lean body masses would both have been 106 lb.

    At 185, with 30% body fat, your fat would weight 55.5 lbs and your lean body mass would be 129.5 lbs

    It is generally accepted that (no matter what we might like to believe), you can't gain any significant muscle while eating a calorie deficit, so I really don't think it is possible for your lean body mass to have gone up by 23.5 lbs.

    I suggest that at least one of your BF readings was wrong. How are you measuring them? The scales that tell you your BF are notoriously flaky (I find that it helps if you dampen your feet before you step on them) and should only be used as a rough guide at best.

    While I agree that her numbers are probably off a bit, it is certainly plausible that she put on some muscle and lost some fat. It's a year's time, she was significantly overwight, and very possibly new to exercise. All of those things lend themselves to gains while in a deficit. Never mind the fact that we don't know she was in a deficit ever week over that time span.

    .
  • Duck_Puddle
    Duck_Puddle Posts: 3,237 Member
    Congrats! That's a fabulous change!

    Where did your original 50% come from? If that came from your scale, it may be low. Many of the scales that give body fat% top out at 50%-so even if you were at 70% BF it way say 50% (depending on the brand/model/etc)

    Of course that would further complicate the calculations since it would imply an even larger gain in LBM.
  • TwelveSticks
    TwelveSticks Posts: 288 Member
    While I agree that her numbers are probably off a bit, it is certainly plausible that she put on some muscle and lost some fat. It's a year's time, she was significantly overwight, and very possibly new to exercise. All of those things lend themselves to gains while in a deficit. Never mind the fact that we don't know she was in a deficit ever week over that time span.

    Well - she did actually say that she's been eating at a deficit while doing this.

    Estimates vary, but it is often considered to be a fair result if you manage to gain 5lb of muscle mass in a year. So unless she's been gorging on proteins and lifting like Schwarzenegger in his heyday, she hasn't gained nearly 24lbs of muscle.

    Fair play for losing 27lbs of weight though. But that doesn't change the suspicious nature of those BF measurements, that's all...
  • NiagaraCheryl
    NiagaraCheryl Posts: 56 Member
    qutoe "So unless she's been gorging on proteins and lifting like Schwarzenegger in his heyday"

    ^ That made me laugh! :laugh:

    OK - to answer some questions, I have been eating at a deficit for the past year, but not a huge deficit. I sit at a desk all day and dont have a lot of room between my TDEE and BMR, so about 300 cal a day deficit is good for me.

    I have been going to a gym for the past 5 years. However, I wasn't really regular and I wasn't very conscientous about my workout. So we can really discount most of that. The past year I've been working out properly - very regularly unless I was sick or on vacation. And I've been leaving the gym far more sweatier than I ever did before.

    My orginal calculation of 50% body fat was from the gym, my bathroom scale and the on-line calculators. They were all pretty much in agreement on this.

    Regardless if the numbers are 100% accurate or not, I think there is still some sort progress going on.
  • jacksonpt
    jacksonpt Posts: 10,413 Member
    qutoe "So unless she's been gorging on proteins and lifting like Schwarzenegger in his heyday"

    ^ That made me laugh! :laugh:

    OK - to answer some questions, I have been eating at a deficit for the past year, but not a huge deficit. I sit at a desk all day and dont have a lot of room between my TDEE and BMR, so about 300 cal a day deficit is good for me.

    I have been going to a gym for the past 5 years. However, I wasn't really regular and I wasn't very conscientous about my workout. So we can really discount most of that. The past year I've been working out properly - very regularly unless I was sick or on vacation. And I've been leaving the gym far more sweatier than I ever did before.

    My orginal calculation of 50% body fat was from the gym, my bathroom scale and the on-line calculators. They were all pretty much in agreement on this.

    Regardless if the numbers are 100% accurate or not, I think there is still some sort progress going on.

    Exactly. I think that's exactly the thing to take away from all this. Numbers are never exact/accurate, but they do indicate things moving in the right direction.

    Very nicely done.
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