question about projecting body fat percentage

peacemongernc

I don't know if anyone can predict the answer to this, or if there are too many variables, but I've been trying to figure out how realistic my goal weight is... or how desirable it is. No reason I need to know this... just something to keep me up at night pondering things when I ought to be sleeping.

When I started this journey I weighed 304 pounds. According to the little hand held body fat calculator at my gym (I realize they aren't all that accurate), I was 49% BF at that starting weight. This was based on setting the calculator to "athlete", which I clearly was not, but this is how my trainer does things for the sake of consistency.

Now, using the same calculator, I am 35.4% body fat at 218 pounds. Still set on "athlete". (I'm guessing this changes the % by about 4% or 5%, but I really don't know.

But regardless of how accurate the reading is, I assume that it is accurate that I have lost 13.6% BF, even if the actual percentage is higher than 35.4%.

Is it reasonable to assume that as my weight continues to decrease, that my BF% will continue to fall at a similar rate? Based on this, is it reasonable to assume that when I get to 165 pounds that my BF% will be, with that same calculator, still set on "athlete", under 20%? Maybe as low as 18% (if my math is right, which is very questionable)?

Based on my height/age/sex/ 165 pounds would be too heavy for me, but I've always thought I am a much larger, or at least much more muscular build than other women my size. If my math on this, and my assumptions about continuing changes in BF%, are correct, 165 actually sounds like a pretty good weight, even if I'm not really an athlete.

But I've also seen many people who thought they were larger than their peers and then lost weight and found out that they weren't. I would sort of love for that to be the case, but I really do think I'm more linebacker than quarterback.

I suppose ultimately the way to know is to get there are see what's what. But, as I said, this is the math that kept my brain spinning at 2AM last night.

So, all you scientific athletes out there... what do you think?

Shannon

peacemongernc

I found this: http://www.acefitness.org/blog/112/what-are-the-guidelines-for-percentage-of-body-fat

Is that an accurate way to predict how much I would need to lose?

WendyTerry420

It's interesting. I don't know your height, but at 5'4" and my starting weight of 263 pounds, the calculators showed me at 67.7% body fat.

For what it's worth, my goal weight is 150 pounds.

peacemongernc

It's interesting. I don't know your height, but at 5'4" and my starting weight of 263 pounds, the calculators showed me at 67.7% body fat.

For what it's worth, my goal weight is 150 pounds.

I'm 5'7", and I'm sure that I was actually more than 50% BF when I started. I don't doubt that. But as I said, I think I'm a linebacker and not a quarterback... as much as I'd like to be dainty, I just don't think it is in the cards for me. I'd love to be wrong about that!!

WendyTerry420

I found this: http://www.acefitness.org/blog/112/what-are-the-guidelines-for-percentage-of-body-fat

Is that an accurate way to predict how much I would need to lose?

That is very similar to other formulas that I've seen. It also calculates to my goal weight exactly, so personally, I like it. :bigsmile:

WendyTerry420

It's interesting. I don't know your height, but at 5'4" and my starting weight of 263 pounds, the calculators showed me at 67.7% body fat.

For what it's worth, my goal weight is 150 pounds.

I'm 5'7", and I'm sure that I was actually more than 50% BF when I started. I don't doubt that. But as I said, I think I'm a linebacker and not a quarterback... as much as I'd like to be dainty, I just don't think it is in the cards for me. I'd love to be wrong about that!!

Same here. This is why my goal weight is 150 instead of 115. I haven't been 115 since junior high. When I started lifting weights in high school, my weight went up, even though no one could guess my weight from looking at me. I always weighed more and wore a larger pants size than people ever believed back then.

xsmilexforxmex

http://www.fat2fitradio.com/tools/

With the military one it calculates you body fat%.. if you go to the next step it will calculate your goal weight based on your goal body fat %

numbers will probably be off from what your trainer got but maybe it's a good starting point?

pixietoes

I find that fat2fit tool very helpful myself. It was very easy to use and of course it's easy to like something that confirms what you already thought.

peacemongernc

Thank you all for your input! Great ideas. Next time I'm losing sleep over silly numbers, I'll check those out instead of trying to run the numbers in my head. Probably tonight. LOL!

Thank you!

Shannon

rkr22401

Goal weight = current lean body mass divided by (1 - goal BF%)

(Assuming your goal is to maintain current lean body mass).

Using your numbers (218 lb and 35.5%) your current lean mass is 140 lb. That seems a little high, which might indicate actual BF% is higher than 35.5%, but not knowing your height, etc, who knows?

For now, let's assume numbers are accurate and assume your goal BF% is 18% just to pick a number.

Goal weight = 140 / 0.82 = 170 lb.

If your current BF% were 40%, your goal weight would be 159 lb at 18%

If currently 45%, goal weight would be 146 lb.

You get the idea.

peacemongernc

Goal weight = current lean body mass divided by (1 - goal BF%)

(Assuming your goal is to maintain current lean body mass).

Using your numbers (218 lb and 35.5%) your current lean mass is 140 lb. That seems a little high, which might indicate actual BF% is higher than 35.5%, but not knowing your height, etc, who knows?

For now, let's assume numbers are accurate and assume your goal BF% is 18% just to pick a number.

Goal weight = 140 / 0.82 = 170 lb.

If your current BF% were 40%, your goal weight would be 159 lb at 18%

If currently 45%, goal weight would be 146 lb.

You get the idea.

Thank you very much! So assuming my numbers are correct within 5%, (I suspect they are in the neighborhood of 3% to 5% off), my goal of 164 is a perfect ballpark number. It's a reasonable place to start, anyway.

waldo56

Remember you will lose lean mass right along with fat.

How much lean mass you lose will greatly depend on how much strength training you do (and other details like protein intake to go along with it).

Everyone will lose some lean mass, it is just a side effect of there being less of you, but it is possible (and likely) without hard strength training that your BF% will drop to a point, and then stay stable or even rise as your weight continues to drop (skinny-fat), as your body consumes your lean mass, conserving your fat.

peacemongernc

Thank you for that, too. That is actually part of what I'm trying to figure out. Out of the 86 pounds I've lost, if I can assume that the BF% calculators are consistent, even if they aren't exactly accurate, about 15% of each pound I've lost has been lean. I'm pretty happy about that number considering I've heard that I could expect to lose 25% lean for each pound, so I must be doing something right.

All of this together is what makes me think that if I continue to work hard at the gym, even though I'm only 5' 7" tall, that 164 number for my goal might be okay. That is the very tippy top of the "acceptable" BMI numbers, though, before I would hit overweight.

Even though it would mean more work, there is a part of me that would rather find out that I need to get down in the 140s... it would mean I was "average", whatever that means... and I would love to be average for once. I've always felt a little like the hulk, even when I was thinner.

But, in mental and physical preparation for the fact that I may indeed be a hulky woman, I've made the decision to go with that and lift heavy. I've always been able to lift more than other woman, I might as well develop the talent, right? I started lifting weights, sort of without much direction, the end of August, and I'm up to a 100 pound bench press. I think I need to find some sort of program so I'm not just flinging weights around without a plan.

When I get done if I find out I'm average, and I need to drop into the 140s, I'll be more than happy to work with that, too!

Thanks everybody!